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Sample records for completely uncertain dc

  1. An Improved Method for Completely Uncertain Biological Network Alignment

    PubMed Central

    Shen, Bin; Zhao, Muwei; Zhong, Wei; He, Jieyue

    2015-01-01

    With the continuous development of biological experiment technology, more and more data related to uncertain biological networks needs to be analyzed. However, most of current alignment methods are designed for the deterministic biological network. Only a few can solve the probabilistic network alignment problem. However, these approaches only use the part of probabilistic data in the original networks allowing only one of the two networks to be probabilistic. To overcome the weakness of current approaches, an improved method called completely probabilistic biological network comparison alignment (C_PBNA) is proposed in this paper. This new method is designed for complete probabilistic biological network alignment based on probabilistic biological network alignment (PBNA) in order to take full advantage of the uncertain information of biological network. The degree of consistency (agreement) indicates that C_PBNA can find the results neglected by PBNA algorithm. Furthermore, the GO consistency (GOC) and global network alignment score (GNAS) have been selected as evaluation criteria, and all of them proved that C_PBNA can obtain more biologically significant results than those of PBNA algorithm. PMID:26000284

  2. Piezometer completion report for borehole cluster sites DC-19, DC-20, and DC-22

    SciTech Connect

    Jackson, R.L.; Diediker, L.D.; Ledgerwood, R.K.; Veatch, M.D.

    1984-07-01

    This report describes the design and installation of multi-level piezometers at borehole cluster sites DC-19, DC-20 and DC-22. The network of borehole cluster sites will provide facilities for multi-level water-level monitoring across the RRL for piezometer baseline monitoring and for large-scale hydraulic stress testing. These groundwater-monitoring facilities were installed between August 1983 and March 1984. Three series of piezometer nests (A-, C- and D-series) were installed in nine hydrogeologic units (monitoring horizons) within the Columbia River Basalt Group at each borehole cluster site. In addition to the piezometer facilities, a B-series pumping well was installed at borehole cluster sites DC-20 and DC-22. The A-series piezometer nest monitors the basal Ringold sediments and the Rattlesnake Ridge interbed. The C-series piezometer nests monitors the six deepest horizons, which are in increasing depth, the Priest Rapids interflow, Sentinel Gap flow top, Ginkgo flow top, Rocky Coulee flow top, Cohassett flow top and Umtanum flow top. The D-series piezometer monitors the Mabton interbed. The B-series pumping well was completed in the Priest Rapids interflow. 21 refs., 6 figs., 6 tabs.

  3. Piezometer completion report for borehold cluster sites DC-19, DC-20 and DC-22

    SciTech Connect

    Jackson, R.L.; Diediker, L.D.; Ledgerwood, R.K.; Veatch, M.D.

    1984-07-01

    This report describes the design and installation of multi-level piezometers at borehole cluster sites DC-19, DC-20 and DC-22. The network of borehole cluster sites will provide facilities for multi-level water-level monitoring across the RRL for piezometer baseline monitoring and for large-scale hydraulic stress testing. These groundwater-monitoring facilities were installed between August 1983 and March 1984. Three series of piezometer nests (A-, C- and D-series) were installed in nine hydrogeologic units (monitoring horizons) within the Columbia River Basalt Group at each borehole cluster site. In addition to the piezometer facilities, a B-series pumping well was installed at borehole cluster sites DC-20 and DC-22. The A-series piezometer nest monitors the basal Ringold sediments and the Rattlesnake Ridge interbed. The C-series piezometer nests monitors the six deepest horizons, which are in increasing depth, the Priest Rapids interflow. 21 refs., 6 figs., 14 tabs.

  4. Incentive contract design in project management with serial tasks and uncertain completion times

    NASA Astrophysics Data System (ADS)

    Yang, Kai; Zhao, Ruiqing; Lan, Yanfei

    2016-04-01

    This article investigates an incentive contract design problem for a project manager who operates a project consisting of multiple tasks performed sequentially by different subcontractors in which all task completion times are uncertain and described by fuzzy variables. On the basis of an expected value criterion and a critical value criterion, two classes of fuzzy bilevel programming models are developed. In the case where the uncertain task completion times are mutually independent, each model can first be decomposed into multiple equivalent sub-models by taking advantage of the structural characteristics, and then a two-step optimization method is employed to derive the optimal incentive contract in each sub-model. In a more general case where the uncertain task completion times are correlative, the approximation approach (AA) technique is adopted first in order to evaluate the objective functions involving fuzzy parameters, which are usually difficult to convert into their crisp equivalents. Then, an AA-based hybrid genetic algorithm integrated with the golden search method and variable neighbourhood search is designed to solve the proposed fuzzy bilevel programming models. Finally, a numerical example of a construction project is conducted to demonstrate the modelling idea and the effectiveness of the proposed methods.

  5. Complete Genome Sequence of the Dairy Isolate Lactobacillus acidipiscis ACA-DC 1533

    PubMed Central

    Kazou, Maria; Alexandraki, Voula; Pot, Bruno; Tsakalidou, Effie

    2017-01-01

    ABSTRACT Lactobacillus acidipiscis is a Gram-positive lactic acid bacterium belonging to the Lactobacillus salivarius clade. Here, we present the first complete genome sequence of L. acidipiscis isolated from traditional Greek Kopanisti cheese. Strain ACA-DC 1533 may play a key role in the strong organoleptic characteristics of Kopanisti cheese. PMID:28126948

  6. Complete synchronization of uncertain chaotic systems via a single proportional adaptive controller: A comparative study

    SciTech Connect

    Ahmad, Israr Saaban, Azizan Bin Ibrahim, Adyda Binti; Shahzad, Mohammad

    2015-12-11

    This paper addresses a comparative computational study on the synchronization quality, cost and converging speed for two pairs of identical chaotic and hyperchaotic systems with unknown time-varying parameters. It is assumed that the unknown time-varying parameters are bounded. Based on the Lyapunov stability theory and using the adaptive control method, a single proportional controller is proposed to achieve the goal of complete synchronizations. Accordingly, appropriate adaptive laws are designed to identify the unknown time-varying parameters. The designed control strategy is easy to implement in practice. Numerical simulations results are provided to verify the effectiveness of the proposed synchronization scheme.

  7. The complete genome sequence of the yogurt isolate Streptococcus thermophilus ACA-DC 2.

    PubMed

    Alexandraki, Voula; Kazou, Maria; Blom, Jochen; Pot, Bruno; Tsakalidou, Effie; Papadimitriou, Konstantinos

    2017-01-01

    Streptococcus thermophilus ACA-DC 2 is a newly sequenced strain isolated from traditional Greek yogurt. Among the 14 fully sequenced strains of S. thermophilus currently deposited in the NCBI database, the ACA-DC 2 strain has the smallest chromosome, containing 1,731,838 bp. The annotation of its genome revealed the presence of 1,850 genes, including 1,556 protein-coding genes, 70 RNA genes and 224 potential pseudogenes. A large number of pseudogenes were identified. This was also accompanied by the absence of pathogenic features suggesting evolution of strain ACA-DC 2 through genome decay processes, most probably due to adaptation to the milk ecosystem. Analysis revealed the existence of one complete lactose-galactose operon, several proteolytic enzymes, one exopolysaccharide cluster, stress response genes and four putative antimicrobial peptides. Interestingly, one CRISPR-cas system and one orphan CRISPR, both carrying only one spacer, were predicted indicating low activity or inactivation of the cas proteins. Nevertheless, four putative restriction-modification systems were determined that may compensate any deficiencies of the CRISPR-cas system. Furthermore, whole genome phylogeny indicated three distinct clades within S. thermophilus. Comparative analysis among selected strains representative for each clade, including strain ACA-DC 2, revealed a high degree of conservation at the genomic scale, but also strain specific regions. Unique genes and genomic islands of strain ACA-DC 2 contained a number of genes potentially acquired through horizontal gene transfer events, that could be related to important technological properties for dairy starters. Our study suggests genomic traits in strain ACA-DC 2 compatible to the production of dairy fermented foods.

  8. Comparison of the complete genome sequences of Pseudomonas syringae pv. syringae B728a and pv. tomato DC3000

    SciTech Connect

    Feil, H; Feil, W S; Chain, P; Larimer, F; DiBartolo, G; Copeland, A; Lykidis, A; Trong, S; Nolan, M; Goltsman, E; Thiel, J; Malfatti, S; Loper, J E; Lapidus, A; Detter, J C; Land, M; Richardson, P M; Kyrpides, N C; Ivanova, N; Lindow, S E

    2005-07-14

    The complete genomic sequence of Pseudomonas syringae pathovar syringae B728a (Pss B728a), has been determined and is compared with that of Pseudomonas syringae pv. tomato DC3000 (Pst DC3000). The two pathovars of this economically important species of plant pathogenic bacteria differ in host range and other interactions with plants, with Pss having a more pronounced epiphytic stage of growth and higher abiotic stress tolerance and Pst DC3000 having a more pronounced apoplastic growth habitat. The Pss B728a genome (6.1 megabases) contains a circular chromosome and no plasmid, whereas the Pst DC3000 genome is 6.5 mbp in size, composed of a circular chromosome and two plasmids. While a high degree of similarity exists between the two sequenced Pseudomonads, 976 protein-encoding genes are unique to Pss B728a when compared to Pst DC3000, including large genomic islands likely to contribute to virulence and host specificity. Over 375 repetitive extragenic palindromic sequences (REPs) unique to Pss B728a when compared to Pst DC3000 are widely distributed throughout the chromosome except in 14 genomic islands, which generally had lower GC content than the genome as a whole. Content of the genomic islands vary, with one containing a prophage and another the plasmid pKLC102 of P. aeruginosa PAO1. Among the 976 genes of Pss B728a with no counterpart in Pst DC3000 are those encoding for syringopeptin (SP), syringomycin (SR), indole acetic acid biosynthesis, arginine degradation, and production of ice nuclei. The genomic comparison suggests that several unique genes for Pss B728a such as ectoine synthase, DNA repair, and antibiotic production may contribute to epiphytic fitness and stress tolerance of this organism.

  9. Comparison of the complete genome sequences of Pseudomonas syringae pv. syringae B728a and pv. tomato DC3000

    SciTech Connect

    Feil, Helene; Feil, William; Chain, Patrick S. G.; Larimer, Frank W; DiBartolo, Genevieve; Copeland, A; Lykidis, A; Trong, Stephen; Nolan, Matt; Goltsman, Eugene; Thiel, James; Malfatti, Stephanie; Loper, Joyce E.; Detter, J C; Lapidus, Alla L.; Land, Miriam L; Richardson, P M; Kyrpides, Nikos C; Ivanova, N; Lindow, Steven E.

    2005-01-01

    The complete genomic sequence of Pseudomonas syringae pv. syringae B728a (Pss B728a) has been determined and is compared with that of A syringae pv. tomato DC3000 (Pst DC3000). The two pathovars of this economically important species of plant pathogenic bacteria differ in host range and other interactions with plants, with Pss having a more pronounced epiphytic stage of growth and higher abiotic stress tolerance and Pst DC3000 having a more pronounced apoplastic growth habitat. The Pss B728a genome (6.1 Mb) contains a circular chromosome and no plasmid, whereas the Pst DC3000 genome is 6.5 mbp in size, composed of a circular chromosome and two plasmids. Although a high degree of similarity exists between the two sequenced Pseudomonads, 976 protein-encoding genes are unique to Pss B728a when compared with Pst DC3000, including large genomic islands likely to contribute to virulence and host specificity. Over 375 repetitive extragenic palindromic sequences unique to Pss B728a when compared with Pst DC3000 are widely distributed throughout the chromosome except in 14 genomic islands, which generally had lower GC content than the genome as a whole. Content of the genomic islands varies, with one containing a prophage and another the plasmid pKLC102 of Pseudomonas aeruginosa PAO1. Among the 976 genes of Pss B728a with no counterpart in Pst DC3000 are those encoding for syringopeptin, syringomycin, indole acetic acid biosynthesis, arginine degradation, and production of ice nuclei. The genomic comparison suggests that several unique genes for Pss B728a such as ectoine synthase, DNA repair, and antibiotic production may contribute to the epiphytic fitness and stress tolerance of this organism.

  10. Comparison of the complete genome sequences of Pseudomonassyringae pv. syringae B728a and pv. tomato DC3000.

    SciTech Connect

    Feil, Helene; Feil, William S.; Chain, Patrick; Larimer, Frank; DiBartolo, Genevieve; Copeland, Alex; Lykidis, Athanasios; Trong,Stephen; Nolan, Matt; Goltsman, Eugene; Thiel, James; Malfatti,Stephanie; Loper, Joyce E.; Lapidus, Alla; Detter, John C.; Land, Miriam; Richardson, Paul M.; Kyrpides, Nikos C.; Ivanova, Natalia; Lindow, StevenE.

    2005-04-01

    The complete genomic sequence of Pseudomonas syringaepathovar syringae B728a (Pss B728a), has been determined and is comparedwith that of Pseudomonas syringae pv. tomato DC3000 (Pst DC3000). Thesetwo pathovars of this economically important species of plant pathogenicbacteria differ in host range and apparent patterns of interaction withplants, with Pss having a more pronounced epiphytic stage of growth andhigher abiotic stress tolerance and Pst DC3000 having a more pronouncedapoplastic growth habitat. The Pss B728a genome (6.1 megabases) containsa circular chromosome and no plasmid, whereas the Pst DC3000 genome is6.5 mbp in size, composed of a circular chromosome and two plasmids.While a high degree of similarity exists between the two sequencedPseudomonads, 976 protein-encoding genes are unique to Pss B728a whencompared to Pst DC3000, including large genomic islands likely tocontribute to virulence and host specificity. Over 375 repetitiveextragenic palindromic sequences (REPs) unique to Pss B728a when comparedto Pst DC3000 are widely distributed throughout the chromosome except in14 genomic islands, which generally had lower GC content than the genomeas a whole. Content of the genomic islands vary, with one containing aprophage and another the plasmid pKLC102 of P. aeruginosa PAO1. Among the976 genes of Pss B728a with no counterpart in Pst DC3000 are thoseencoding for syringopeptin (SP), syringomycin (SR), indole acetic acidbiosynthesis, arginine degradation, and production of ice nuclei. Thegenomic comparison suggests that several unique genes for Pss B728a suchas ectoine synthase, DNA repair, and antibiotic production may contributeto epiphytic fitness and stress tolerance of this organism. Pseudomonassyringae, a member of the gamma subgroup of the Proteobacteria, is awidespread bacterial pathogen of many plant species. The species P.syringae is subdivided into approximately 50 pathovars based onpathogenicity and host range. P. syringae is capable of

  11. Complete genome sequence of Dehalogenimonas lykanthroporepellens type strain (BL-DC-9T) and comparison to Dehalococcoides strains

    SciTech Connect

    Siddaramappa, Shivakumara; Delano, Susana; Green, Lance D.; Daligault, Hajnalka E.; Bruce, David; Detter, J. Chris; Tapia, Roxanne; Han, Cliff; Goodwin, Lynne A.; Han, James; Woyke, Tanja; Pitluck, Sam; Pennacchio, Len; Nolan, Matt; Land, Miriam L; Chang, Yun-Juan; Kyrpides, Nikos C; Ovchinnikova, Galina; Hauser, Loren John; Lapidus, Alla L.; Yan, Jun; Bowman, Kimberly; Da Costa, Milton S,; Rainey, Fred A.; Moe, William M.

    2012-01-01

    Dehalogenimonas lykanthroporepellens is the type species of the genus Dehalogenimonas, which belongs to a deeply branching lineage within the phylum Chloroflexi. This strictly anaerobic, mesophilic, non spore forming, Gram negative staining bacterium was first isolated from chlorinated solvent contaminated groundwater at a Superfund site located near Baton Rouge, Louisiana, USA. D. lykanthroporepellens was of interest for genome sequencing for two reasons: (a) its unusual ability to couple growth with reductive dechlorination of environmentally important polychlorinated aliphatic alkanes and (b) its phylogenetic position distant from previously sequenced bacteria. The 1,686,510 bp circular chromosome of strain BL-DC-9{sup T} contains 1,720 predicted protein coding genes, 47 tRNA genes, a single large subunit rRNA (23S-5S) locus, and a single, orphan, small unit rRNA (16S) locus.

  12. Multiplex RT-PCR Amplification of HIV Genes to Create a Completely Autologous DC-Based Immunotherapy for the Treatment of HIV Infection

    PubMed Central

    Tcherepanova, Irina; Harris, Jason; Starr, Aijing; Cleveland, Jaclyn; Ketteringham, Helen; Calderhead, David; Horvatinovich, Joe; Healey, Don; Nicolette, Charles A.

    2008-01-01

    Background Effective therapy for HIV-infected individuals remains an unmet medical need. Promising clinical trials with dendritic cell (DC)-based immunotherapy consisting of autologous DC loaded with autologous virus have been reported, however, these approaches depend on large numbers of HIV virions to generate sufficient doses for even limited treatment regimens. Methodology/Principal Findings The present study describes a novel approach for RT-PCR amplification of HIV antigens. Previously, RT-PCR amplification of autologous viral sequences has been confounded by the high mutation rate of the virus which results in unreliable primer-template binding. To resolve this problem we developed a multiplex RT-PCR strategy that allows reliable strain-independent amplification of highly polymorphic target antigens from any patient and requires neither viral sequence data nor custom-designed PCR primers for each individual. We demonstrate the application of our RT-PCR process to amplify translationally-competent RNA encoding regions of Gag, Vpr, Rev and Nef. The products amplified using this method represent a complex mixture of autologous antigens encoded by viral quasispecies. We further demonstrate that DCs electroporated with in vitro-transcribed HIV RNAs are capable of stimulating poly-antigen-specific CD8+ T cell responses in vitro. Conclusion/Significance This study describes a strategy to overcome patient to patient viral diversity enabling strain-independent RT-PCR amplification of RNAs encoding sequence divergent quasispecies of Gag, Vpr, Rev and Nef from small volumes of infectious plasma. The approach allows creation of a completely autologous therapy that does not require advance knowledge of the HIV genomic sequences, does not have yield limitations and has no intact virus in the final product. The simultaneous use of autologous viral antigens and DCs may provoke broad patient-specific immune responses that could potentially induce effective control of viral

  13. Uncertain thrombophilia markers.

    PubMed

    Franchini, Massimo; Martinelli, Ida; Mannucci, Pier Mannuccio

    2016-01-01

    The development of venous thromboembolism (VTE), which includes deep-vein thrombosis and pulmonary embolism, may be associated with inherited or acquired risk factors that can be measured in plasma or DNA testing. The main inherited thrombophilias include the plasma deficiencies of the natural anticoagulants antithrombin, protein C and S; the gain-of-function mutations factor V Leiden and prothrombin G20210A; some dysfibrinogenaemias and high plasma levels of coagulation factor VIII. Besides these established biomarkers, which usually represent the first-level laboratory tests for thrombophilia screening, a number of additional abnormalities have been less consistently associated with an increased VTE risk. These uncertain causes of thrombophilias will be discussed in this narrative review, focusing on their clinical impact and the underlying pathogenetic mechanisms. Currently, there is insufficient ground to recommend their inclusion within the framework of conventional thrombophilia testing.

  14. How Uncertain is Uncertainty?

    NASA Astrophysics Data System (ADS)

    Vámos, Tibor

    The gist of the paper is the fundamental uncertain nature of all kinds of uncertainties and consequently a critical epistemic review of historical and recent approaches, computational methods, algorithms. The review follows the development of the notion from the beginnings of thinking, via the Aristotelian and Skeptic view, the medieval nominalism and the influential pioneering metaphors of ancient India and Persia to the birth of modern mathematical disciplinary reasoning. Discussing the models of uncertainty, e.g. the statistical, other physical and psychological background we reach a pragmatic model related estimation perspective, a balanced application orientation for different problem areas. Data mining, game theories and recent advances in approximation algorithms are discussed in this spirit of modest reasoning.

  15. Bidirectional DC/DC Converter

    NASA Astrophysics Data System (ADS)

    Pedersen, F.

    2008-09-01

    The presented bidirectional DC/DC converter design concept is a further development of an already existing converter used for low battery voltage operation.For low battery voltage operation a high efficient low parts count DC/DC converter was developed, and used in a satellite for the battery charge and battery discharge function.The converter consists in a bidirectional, non regulating DC/DC converter connected to a discharge regulating Buck converter and a charge regulating Buck converter.The Bidirectional non regulating DC/DC converter performs with relatively high efficiency even at relatively high currents, which here means up to 35Amps.This performance was obtained through the use of power MOSFET's with on- resistances of only a few mille Ohms connected to a special transformer allowing paralleling several transistor stages on the low voltage side of the transformer. The design is patent protected. Synchronous rectification leads to high efficiency at the low battery voltages considered, which was in the range 2,7- 4,3 Volt DC.The converter performs with low switching losses as zero voltage zero current switching is implemented in all switching positions of the converter.Now, the drive power needed, to switch a relatively large number of low Ohm , hence high drive capacitance, power MOSFET's using conventional drive techniques would limit the overall conversion efficiency.Therefore a resonant drive consuming considerable less power than a conventional drive circuit was implemented in the converter.To the originally built and patent protected bidirectional non regulating DC/DC converter, is added the functionality of regulation.Hereby the need for additional converter stages in form of a Charge Buck regulator and a Discharge Buck regulator is eliminated.The bidirectional DC/DC converter can be used in connection with batteries, motors, etc, where the bidirectional feature, simple design and high performance may be useful.

  16. Milliwatt dc/dc Inverter

    NASA Technical Reports Server (NTRS)

    Mclyman, C. W.

    1983-01-01

    Compact dc/dc inverter uses single integrated-circuit package containing six inverter gates that generate and amplify 100-kHz square-wave switching signal. Square-wave switching inverts 10-volt local power to isolated voltage at another desired level. Relatively high operating frequency reduces size of filter capacitors required, resulting in small package unit.

  17. Scheduling in the Face of Uncertain Resource Consumption and Utility

    NASA Technical Reports Server (NTRS)

    Frank, Jeremy; Dearden, Richard

    2003-01-01

    We discuss the problem of scheduling tasks that consume uncertain amounts of a resource with known capacity and where the tasks have uncertain utility. In these circumstances, we would like to find schedules that exceed a lower bound on the expected utility when executed. We show that the problems are NP- complete, and present some results that characterize the behavior of some simple heuristics over a variety of problem classes.

  18. Uncertain programming models for portfolio selection with uncertain returns

    NASA Astrophysics Data System (ADS)

    Zhang, Bo; Peng, Jin; Li, Shengguo

    2015-10-01

    In an indeterminacy economic environment, experts' knowledge about the returns of securities consists of much uncertainty instead of randomness. This paper discusses portfolio selection problem in uncertain environment in which security returns cannot be well reflected by historical data, but can be evaluated by the experts. In the paper, returns of securities are assumed to be given by uncertain variables. According to various decision criteria, the portfolio selection problem in uncertain environment is formulated as expected-variance-chance model and chance-expected-variance model by using the uncertainty programming. Within the framework of uncertainty theory, for the convenience of solving the models, some crisp equivalents are discussed under different conditions. In addition, a hybrid intelligent algorithm is designed in the paper to provide a general method for solving the new models in general cases. At last, two numerical examples are provided to show the performance and applications of the models and algorithm.

  19. Radiation-Tolerant DC-DC Converters

    NASA Technical Reports Server (NTRS)

    Skutt, Glenn; Sable, Dan; Leslie, Leonard; Graham, Shawn

    2012-01-01

    A document discusses power converters suitable for space use that meet the DSCC MIL-PRF-38534 Appendix G radiation hardness level P classification. A method for qualifying commercially produced electronic parts for DC-DC converters per the Defense Supply Center Columbus (DSCC) radiation hardened assurance requirements was developed. Development and compliance testing of standard hybrid converters suitable for space use were completed for missions with total dose radiation requirements of up to 30 kRad. This innovation provides the same overall performance as standard hybrid converters, but includes assurance of radiation- tolerant design through components and design compliance testing. This availability of design-certified radiation-tolerant converters can significantly reduce total cost and delivery time for power converters for space applications that fit the appropriate DSCC classification (30 kRad).

  20. Preparing for an Uncertain Forecast

    ERIC Educational Resources Information Center

    Karolak, Eric

    2011-01-01

    Navigating the world of government relations and public policy can be a little like predicting the weather. One can't always be sure what's in store or how it will affect him/her down the road. But there are common patterns and a few basic steps that can help one best prepare for a change in the forecast. Though the forecast is uncertain, early…

  1. Synchronization effect for uncertain quantum networks

    NASA Astrophysics Data System (ADS)

    Li, Wenlin; Gebremariam, Tesfay; Li, Chong; Song, Heshan

    2017-01-01

    We propose a novel technique for investigating the synchronization effect for uncertain networks with quantum chaotic behaviors in this paper. Through designing a special function to construct Lyapunov function of network and the adaptive laws of uncertain parameters, the synchronization between the uncertain network and the synchronization target can be realized, and the uncertain parameters in state equations of the network nodes are perfectly identified. All the theoretical results are verified by numerical simulations to demonstrate the effectiveness of the proposed synchronization technique.

  2. Uncertain environmental costs and the optimum rate of oil recovery

    SciTech Connect

    Dabirian, S.; Wong, D.C.

    1995-10-01

    The socially optimal rate of oil recovery from a known reservoir is analyzed when enviromental costs are uncertain and planners are either risk neutral or risk averse. It is shown that the rate of oil recovery has the same characteristics whether environmental costs are certain or uncertain. In either case, the rate of oil recovery falls monotonically to zero over the time horizon. However, the planner`s attitude toward risk is an important consideration. Risk averse planners, as a rule, begin oil recovery at a higher rate, reduce the rate of recovery more rapidly, and complete the oil recovery in a shorter time than risk neutral planners. 7 refs., 2 figs.

  3. Algebraic parameters identification of DC motors: methodology and analysis

    NASA Astrophysics Data System (ADS)

    Becedas, J.; Mamani, G.; Feliu, V.

    2010-10-01

    A fast, non-asymptotic, algebraic parameter identification method is applied to an uncertain DC motor to estimate the uncertain parameters: viscous friction coefficient and inertia. In this work, the methodology is developed and analysed, its convergence, a comparative study between the traditional recursive least square method and the algebraic identification method is carried out, and an analysis of the estimator in a noisy system is presented. Computer simulations were carried out to validate the suitability of the identification algorithm.

  4. Adaptable DC offset correction

    NASA Technical Reports Server (NTRS)

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

    2009-01-01

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

  5. Uncertain deduction and conditional reasoning

    PubMed Central

    Evans, Jonathan St. B. T.; Thompson, Valerie A.; Over, David E.

    2015-01-01

    There has been a paradigm shift in the psychology of deductive reasoning. Many researchers no longer think it is appropriate to ask people to assume premises and decide what necessarily follows, with the results evaluated by binary extensional logic. Most every day and scientific inference is made from more or less confidently held beliefs and not assumptions, and the relevant normative standard is Bayesian probability theory. We argue that the study of “uncertain deduction” should directly ask people to assign probabilities to both premises and conclusions, and report an experiment using this method. We assess this reasoning by two Bayesian metrics: probabilistic validity and coherence according to probability theory. On both measures, participants perform above chance in conditional reasoning, but they do much better when statements are grouped as inferences, rather than evaluated in separate tasks. PMID:25904888

  6. Finite-time control of DC-DC buck converters via integral terminal sliding modes

    NASA Astrophysics Data System (ADS)

    Chiu, Chian-Song; Shen, Chih-Teng

    2012-05-01

    This article presents novel terminal sliding modes for finite-time output tracking control of DC-DC buck converters. Instead of using traditional singular terminal sliding mode, two integral terminal sliding modes are introduced for robust output voltage tracking of uncertain buck converters. Different from traditional sliding mode control (SMC), the proposed controller assures finite convergence time for the tracking error and integral tracking error. Furthermore, the singular problem in traditional terminal SMC is removed from this article. When considering worse modelling, adaptive integral terminal SMC is derived to guarantee finite-time convergence under more relaxed stability conditions. In addition, several experiments show better start-up performance and robustness.

  7. D.C. Opportunity Scholarships Boost Reading Scores, Family Satisfaction. WebMemo. No. 2391

    ERIC Educational Resources Information Center

    Lips, Dan

    2009-01-01

    Despite growing evidence of the success of the D.C. Opportunity Scholarship program (DCOSP), its future beyond 2009-2010 remains uncertain. This spring, Congress included legislative language in the Omnibus Appropriations Act requiring that the DCOSP be reauthorized by Congress and authorized by the D.C. City Council before receiving new federal…

  8. Decision making under uncertain categorization

    PubMed Central

    Chen, Stephanie Y.; Ross, Brian H.; Murphy, Gregory L.

    2014-01-01

    Two experiments investigated how category information is used in decision making under uncertainty and whether the framing of category information influences how it is used. Subjects were presented with vignettes in which the categorization of a critical item was ambiguous and were asked to choose among a set of actions with the goal of attaining the desired outcome for the main character in the story. The normative decision making strategy was to base the decision on all possible categories; however, research on a related topic, category-based induction, has found that people often only consider a single category when making predictions when categorization is uncertain. These experiments found that subjects tend to consider multiple categories when making decisions, but do so both when it is and is not appropriate, suggesting that use of multiple categories is not driven by an understanding of whether categories are relevant to the decision. Similarly, although a framing manipulation increased the rate of multiple-category use, it did so in situations in which multiple-category use both was and was not appropriate. PMID:25309475

  9. Efficient dc-to-dc converter

    NASA Technical Reports Server (NTRS)

    Black, J. M.

    1978-01-01

    Circuit consists of chopper section which converts input dc to square wave, followed by bridge-rectifier stage. Chopper gives nearly-ideal switching characteristics, and bridge uses series of full-wave stages rather than less-efficient half-wave rectifiers found in previous circuits. Special features of full-wave circuit allow redundant components to be eliminated, lowering parts count. Circuit can also be adapted for use as dc-to-dc converter or as combination dc-and-ac source.

  10. DC/DC Converter Stability Testing Study

    NASA Technical Reports Server (NTRS)

    Wang, Bright L.

    2008-01-01

    This report presents study results on hybrid DC/DC converter stability testing methods. An input impedance measurement method and a gain/phase margin measurement method were evaluated to be effective to determine front-end oscillation and feedback loop oscillation. In particular, certain channel power levels of converter input noises have been found to have high degree correlation with the gain/phase margins. It becomes a potential new method to evaluate stability levels of all type of DC/DC converters by utilizing the spectral analysis on converter input noises.

  11. Modelling and Simulation of Digital Compensation Technique for dc-dc Converter by Pole Placement

    NASA Astrophysics Data System (ADS)

    Shenbagalakshmi, R.; Sree Renga Raja, T.

    2015-09-01

    A thorough and effective analysis of the dc-dc converters is carried out in order to achieve the system stability and to improve the dynamic performance. A small signal modelling based on state space averaging technique for dc-dc converters is carried out. A digital state feedback gain matrix is derived by pole placement technique in order to achieve the stability of a completely controllable system. A prediction observer for the dc-dc converters is designed and a dynamic compensation (observer plus control law) is provided using separation principle. The output is very much improved with zero output voltage ripples, zero peak overshoot, and much lesser settling time in the range of ms and with higher overall efficiency (>90 %).

  12. DC source assemblies

    DOEpatents

    Campbell, Jeremy B; Newson, Steve

    2013-02-26

    Embodiments of DC source assemblies of power inverter systems of the type suitable for deployment in a vehicle having an electrically grounded chassis are provided. An embodiment of a DC source assembly comprises a housing, a DC source disposed within the housing, a first terminal, and a second terminal. The DC source also comprises a first capacitor having a first electrode electrically coupled to the housing, and a second electrode electrically coupled to the first terminal. The DC source assembly further comprises a second capacitor having a first electrode electrically coupled to the housing, and a second electrode electrically coupled to the second terminal.

  13. Uncertain Policy for an Uncertain World: The Case of Social Security

    ERIC Educational Resources Information Center

    Sabelhaus, John; Topoleski, Julie

    2007-01-01

    Analysis and discussion of Social Security policy are usually based on expected fiscal and societal outcomes. However, future demographic and economic trends are uncertain, and thus ultimate outcomes for aggregate system financial flows and the distribution of taxes and benefits across generations are uncertain. This paper analyzes a…

  14. Complete Makeover

    NASA Technical Reports Server (NTRS)

    2004-01-01

    [figure removed for brevity, see original site]

    Released July 23, 2004 The atmosphere of Mars is a dynamic system. Water-ice clouds, fog, and hazes can make imaging the surface from space difficult. Dust storms can grow from local disturbances to global sizes, through which imaging is impossible. Seasonal temperature changes are the usual drivers in cloud and dust storm development and growth.

    Eons of atmospheric dust storm activity has left its mark on the surface of Mars. Dust carried aloft by the wind has settled out on every available surface; sand dunes have been created and moved by centuries of wind; and the effect of continual sand-blasting has modified many regions of Mars, creating yardangs and other unusual surface forms.

    We finish our look at Mars's dynamic atmosphere with an image of the surface that has been completely modified by the wind. Even the small ridges that remain have been ground down to a cliff-face with a 'tail' of eroded material. The crosshatching shows that the wind regime has remained mainly E/W to ENE/WSW.

    Image information: VIS instrument. Latitude 8.9, Longitude 221 East (139 West). 19 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip

  15. 76 FR 13926 - Airworthiness Directives; The Boeing Company Model DC-8-11, DC-8-12, DC-8-21, DC-8-31, DC-8-32...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-15

    ... Model DC-8-11, DC-8- 12, DC-8-21, DC-8-31, DC-8-32, DC-8-33, DC-8-41, DC-8-42, and DC-8-43 Airplanes; DC-8-50 Series Airplanes; DC-8F-54 and DC-8F-55 Airplanes; DC-8-60 Series Airplanes; DC-8-60F Series Airplanes; DC-8-70 Series Airplanes; and DC-8-70F Series Airplanes AGENCY:......

  16. 75 FR 61989 - Airworthiness Directives; McDonnell Douglas Corporation Model DC-8-31, DC-8-32, DC-8-33, DC-8-41...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-07

    ... Corporation Model DC- 8-31, DC-8-32, DC-8-33, DC-8-41, DC-8-42, and DC-8-43 Airplanes; Model DC-8-50 Series Airplanes; Model DC-8F-54 and DC-8F-55 Airplanes; Model DC-8-60 Series Airplanes; Model DC-8-60F Series Airplanes; Model DC-8- 70 Series Airplanes; and Model DC-8-70F Series Airplanes AGENCY:......

  17. Learning to Learn about Uncertain Feedback

    ERIC Educational Resources Information Center

    Faraut, Mailys C. M.; Procyk, Emmanuel; Wilson, Charles R. E.

    2016-01-01

    Unexpected outcomes can reflect noise in the environment or a change in the current rules. We should ignore noise but shift strategy after rule changes. How we learn to do this is unclear, but one possibility is that it relies on learning to learn in uncertain environments. We propose that acquisition of latent task structure during learning to…

  18. Output feedback trajectory stabilization of the uncertainty DC servomechanism system.

    PubMed

    Aguilar-Ibañez, Carlos; Garrido-Moctezuma, Ruben; Davila, Jorge

    2012-11-01

    This work proposes a solution for the output feedback trajectory-tracking problem in the case of an uncertain DC servomechanism system. The system consists of a pendulum actuated by a DC motor and subject to a time-varying bounded disturbance. The control law consists of a Proportional Derivative controller and an uncertain estimator that allows compensating the effects of the unknown bounded perturbation. Because the motor velocity state is not available from measurements, a second-order sliding-mode observer permits the estimation of this variable in finite time. This last feature allows applying the Separation Principle. The convergence analysis is carried out by means of the Lyapunov method. Results obtained from numerical simulations and experiments in a laboratory prototype show the performance of the closed loop system.

  19. DC-to-DC switching converter

    NASA Technical Reports Server (NTRS)

    Cuk, Slobodan M. (Inventor); Middlebrook, Robert D. (Inventor)

    1980-01-01

    A dc-to-dc converter having nonpulsating input and output current uses two inductances, one in series with the input source, the other in series with the output load. An electrical energy transferring device with storage, namely storage capacitance, is used with suitable switching means between the inductances to DC level conversion. For isolation between the source and load, the capacitance may be divided into two capacitors coupled by a transformer, and for reducing ripple, the inductances may be coupled. With proper design of the coupling between the inductances, the current ripple can be reduced to zero at either the input or the output, or the reduction achievable in that way may be divided between the input and output.

  20. Multilevel DC link inverter

    DOEpatents

    Su, Gui-Jia

    2003-06-10

    A multilevel DC link inverter and method for improving torque response and current regulation in permanent magnet motors and switched reluctance motors having a low inductance includes a plurality of voltage controlled cells connected in series for applying a resulting dc voltage comprised of one or more incremental dc voltages. The cells are provided with switches for increasing the resulting applied dc voltage as speed and back EMF increase, while limiting the voltage that is applied to the commutation switches to perform PWM or dc voltage stepping functions, so as to limit current ripple in the stator windings below an acceptable level, typically 5%. Several embodiments are disclosed including inverters using IGBT's, inverters using thyristors. All of the inverters are operable in both motoring and regenerating modes.

  1. Feature selection for linear SVMs under uncertain data: robust optimization based on difference of convex functions algorithms.

    PubMed

    Le Thi, Hoai An; Vo, Xuan Thanh; Pham Dinh, Tao

    2014-11-01

    In this paper, we consider the problem of feature selection for linear SVMs on uncertain data that is inherently prevalent in almost all datasets. Using principles of Robust Optimization, we propose robust schemes to handle data with ellipsoidal model and box model of uncertainty. The difficulty in treating ℓ0-norm in feature selection problem is overcome by using appropriate approximations and Difference of Convex functions (DC) programming and DC Algorithms (DCA). The computational results show that the proposed robust optimization approaches are superior than a traditional approach in immunizing perturbation of the data.

  2. The empirical accuracy of uncertain inference models

    NASA Technical Reports Server (NTRS)

    Vaughan, David S.; Yadrick, Robert M.; Perrin, Bruce M.; Wise, Ben P.

    1987-01-01

    Uncertainty is a pervasive feature of the domains in which expert systems are designed to function. Research design to test uncertain inference methods for accuracy and robustness, in accordance with standard engineering practice is reviewed. Several studies were conducted to assess how well various methods perform on problems constructed so that correct answers are known, and to find out what underlying features of a problem cause strong or weak performance. For each method studied, situations were identified in which performance deteriorates dramatically. Over a broad range of problems, some well known methods do only about as well as a simple linear regression model, and often much worse than a simple independence probability model. The results indicate that some commercially available expert system shells should be used with caution, because the uncertain inference models that they implement can yield rather inaccurate results.

  3. Sensitivity in risk analyses with uncertain numbers.

    SciTech Connect

    Tucker, W. Troy; Ferson, Scott

    2006-06-01

    Sensitivity analysis is a study of how changes in the inputs to a model influence the results of the model. Many techniques have recently been proposed for use when the model is probabilistic. This report considers the related problem of sensitivity analysis when the model includes uncertain numbers that can involve both aleatory and epistemic uncertainty and the method of calculation is Dempster-Shafer evidence theory or probability bounds analysis. Some traditional methods for sensitivity analysis generalize directly for use with uncertain numbers, but, in some respects, sensitivity analysis for these analyses differs from traditional deterministic or probabilistic sensitivity analyses. A case study of a dike reliability assessment illustrates several methods of sensitivity analysis, including traditional probabilistic assessment, local derivatives, and a ''pinching'' strategy that hypothetically reduces the epistemic uncertainty or aleatory uncertainty, or both, in an input variable to estimate the reduction of uncertainty in the outputs. The prospects for applying the methods to black box models are also considered.

  4. Communicating Uncertain News in Cancer Consultations.

    PubMed

    Alby, Francesca; Zucchermaglio, Cristina; Fatigante, Marilena

    2016-07-14

    In cancer communication, most of the literature is in the realm of delivering bad news while much less attention has been given to the communication of uncertain news around the diagnosis and the possible outcomes of the illness. Drawing on video-recorded cancer consultations collected in two Italian hospitals, this article analyzes three communication practices used by oncologists to interactionally manage the uncertainty during the visit: alternating between uncertain bad news and certain good news, anticipating scenarios, and guessing test results. Both diagnostic and personal uncertainties are not hidden to the patient, yet they are reduced through these practices. Such communication practices are present in 32 % of the visits in the data set, indicating that the interactional management of uncertainty is a relevant phenomenon in oncological encounters. Further studies are needed to improve both its understanding and its teaching.

  5. The uncertain response in humans and animals

    NASA Technical Reports Server (NTRS)

    Smith, J. D.; Shields, W. E.; Schull, J.; Washburn, D. A.; Rumbaugh, D. M. (Principal Investigator)

    1997-01-01

    There has been no comparative psychological study of uncertainty processes. Accordingly, the present experiments asked whether animals, like humans, escape adaptively when they are uncertain. Human and animal observers were given two primary responses in a visual discrimination task, and the opportunity to escape from some trials into easier ones. In one psychophysical task (using a threshold paradigm), humans escaped selectively the difficult trials that left them uncertain of the stimulus. Two rhesus monkeys (Macaca mulatta) also showed this pattern. In a second psychophysical task (using the method of constant stimuli), some humans showed this pattern but one escaped infrequently and nonoptimally. Monkeys showed equivalent individual differences. The data suggest that escapes by humans and monkeys are interesting cognitive analogs and may reflect controlled decisional processes prompted by the perceptual ambiguity at threshold.

  6. DC-DC conversion powering schemes for the CMS tracker at Super-LHC

    NASA Astrophysics Data System (ADS)

    Klein, K.; Feld, L.; Jussen, R.; Karpinski, W.; Merz, J.; Sammet, J.

    2010-07-01

    The CMS experiment at the Large Hadron Collider (LHC) at CERN, Geneva, houses the largest silicon strip tracker ever built. For the foreseen luminosity upgrade of the LHC, the Super-LHC, however, a completely new silicon tracker will have to be constructed. One out of several major improvements currently under consideration is the implementation of a track trigger, with tracking information being provided to the first level trigger. Such an intelligent tracker design, utilising fast digital readout electronics, will most certainly lead to an increased power consumption, compared to today's tracker. In combination with the desire to reduce the amount of passive material inside the tracking volume and the impracticality to exchange or even add additional supply cables, a novel powering scheme will be inevitable. In this article a powering scheme based on DC-DC conversion is proposed, and requirements for the DC-DC converters are discussed. Studies of important DC-DC converter quantities such as the power efficiency, conducted and radiated noise levels, and material budget are presented, and a possible implementation of DC-DC buck converters into one proposed track trigger layout is sketched.

  7. Constructor:synthesizing information about uncertain variables.

    SciTech Connect

    Tucker, W. Troy; Ferson, Scott; Hajagos, Janos; Myers, David S.

    2005-09-01

    Constructor is software for the Microsoft Windows microcomputer environment that facilitates the collation of empirical information and expert judgment for the specification of probability distributions, probability boxes, random sets or Dempster-Shafer structures from data, qualitative shape information, constraints on moments, order statistics, densities, and coverage probabilities about uncertain unidimensional quantities. These quantities may be real-valued, integer-valued or logical values.

  8. DC Magnetics Measurement System Design

    NASA Technical Reports Server (NTRS)

    Mastny, Timothy

    2012-01-01

    This report will detail the updates to the magnetics measurement system design and testing procedures that are required for performing static (DC) magnetics testing of future flight hardware. An older magnetics testing system had to be integrated with new procedures and hardware to meet the demands of future testing programs and accommodate an upcoming magnetics tests. The next test will be for the Geostationary Operational Environmental Satellite R-Series (GOES-R), which will verify that the SAFT Battery component meets its specifications for magnetic cleanliness. The satellite is scheduled to launch in 2015 with magnetics testing to be completed on the battery in November 2012.

  9. Uncertain relational reasoning in the parietal cortex.

    PubMed

    Ragni, Marco; Franzmeier, Imke; Maier, Simon; Knauff, Markus

    2016-04-01

    The psychology of reasoning is currently transitioning from the study of deductive inferences under certainty to inferences that have degrees of uncertainty in both their premises and conclusions; however, only a few studies have explored the cortical basis of uncertain reasoning. Using transcranial magnetic stimulation (TMS), we show that areas in the right superior parietal lobe (rSPL) are necessary for solving spatial relational reasoning problems under conditions of uncertainty. Twenty-four participants had to decide whether a single presented order of objects agreed with a given set of indeterminate premises that could be interpreted in more than one way. During the presentation of the order, 10-Hz TMS was applied over the rSPL or a sham control site. Right SPL TMS during the inference phase disrupted performance in uncertain relational reasoning. Moreover, we found differences in the error rates between preferred mental models, alternative models, and inconsistent models. Our results suggest that different mechanisms are involved when people reason spatially and evaluate different kinds of uncertain conclusions.

  10. 75 FR 6160 - Airworthiness Directives; McDonnell Douglas Corporation Model DC-10-10, DC-10-10F, DC-10-15, DC...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-08

    ... Douglas Corporation Model DC- 10-10, DC-10-10F, DC-10-15, DC-10-30, DC-10-30F (KC-10A and KDC-10), DC-10... airworthiness directive (AD) for certain Model DC-10-10, DC-10-10F, DC-10-15, DC-10-30, DC-10-30F (KC- 10A and... would require a one-time installation of electrical bonding jumpers for the fill valve controllers...

  11. Forback DC-to-DC converter

    NASA Technical Reports Server (NTRS)

    Lukemire, Alan T. (Inventor)

    1993-01-01

    A pulse-width modulated DC-to-DC power converter including a first inductor, i.e. a transformer or an equivalent fixed inductor equal to the inductance of the secondary winding of the transformer, coupled across a source of DC input voltage via a transistor switch which is rendered alternately conductive (ON) and nonconductive (OFF) in accordance with a signal from a feedback control circuit is described. A first capacitor capacitively couples one side of the first inductor to a second inductor which is connected to a second capacitor which is coupled to the other side of the first inductor. A circuit load shunts the second capacitor. A semiconductor diode is additionally coupled from a common circuit connection between the first capacitor and the second inductor to the other side of the first inductor. A current sense transformer generating a current feedback signal for the switch control circuit is directly coupled in series with the other side of the first inductor so that the first capacitor, the second inductor and the current sense transformer are connected in series through the first inductor. The inductance values of the first and second inductors, moreover, are made identical. Such a converter topology results in a simultaneous voltsecond balance in the first inductance and ampere-second balance in the current sense transformer.

  12. Forback DC-to-DC converter

    NASA Technical Reports Server (NTRS)

    Lukemire, Alan T. (Inventor)

    1995-01-01

    A pulse-width modulated DC-to-DC power converter including a first inductor, i.e. a transformer or an equivalent fixed inductor equal to the inductance of the secondary winding of the transformer, coupled across a source of DC input voltage via a transistor switch which is rendered alternately conductive (ON) and nonconductive (OFF) in accordance with a signal from a feedback control circuit is described. A first capacitor capacitively couples one side of the first inductor to a second inductor which is connected to a second capacitor which is coupled to the other side of the first inductor. A circuit load shunts the second capacitor. A semiconductor diode is additionally coupled from a common circuit connection between the first capacitor and the second inductor to the other side of the first inductor. A current sense transformer generating a current feedback signal for the switch control circuit is directly coupled in series with the other side of the first inductor so that the first capacitor, the second inductor and the current sense transformer are connected in series through the first inductor. The inductance values of the first and second inductors, moreover, are made identical. Such a converter topology results in a simultaneous voltsecond balance in the first inductance and ampere-second balance in the current sense transformer.

  13. Exponential passivity for output feedback stabilisation of nonlinear uncertain systems

    NASA Astrophysics Data System (ADS)

    Benabdallah, Amel

    2010-11-01

    In this article, we address the problem of stabilisation by output feedback for a class of uncertain systems. We consider uncertain systems with a nominal part which is affine in the control and an uncertain part which is norm bounded by a known function. We propose an output feedback such that the closed loop system is globally exponentially stable.

  14. 19. Photocopy of photograph (source uncertain; probably Bucks County Historical ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    19. Photocopy of photograph (source uncertain; probably Bucks County Historical Society) ca. 1916, photographer unknown SHOWING CONSTRUCTION ESSENTIALLY COMPLETED. MERCER'S CAPTION READS: 'ON SATURDAY EVENING, NOVEMBER 13th AT 5: 15 P.M. THE WORKMEN HAVING AT FIVE O'CLOCK FINISHED THE CONSTRUCTION OF THE NEW BUILDING OF THE MUSEUM OF THE BUCKS COUNTY HISTORICAL SOCIETY AT DOYLESTOWN, A BAND OF TRAVELLING MUSICIANS STOPPED UNASKED AT NO. 196 GREEN STREET OPPOSITE THE SOUTHEAST GABLE OF THE BUILDING AND I HEARD THEM PLAY THE GERMAN SONG SHOWN BELOW, TRANSLATED 'WE HAD BUILT A STATELY HOUSE, AND DEDICATED IT TO GOD, AGAINST RAIN, STORM AND DISASTER' I CALLED THEM BACK TO PLAY IT AGAIN, BUT THEY MISUNDERSTOOD ME AND WENT AWAY. HENRY C. MERCER' - Mercer Museum, Pine & Ashland Streets, Doylestown, Bucks County, PA

  15. Optimal Decision Making in a Class of Uncertain Systems Based on Uncertain Variables

    NASA Astrophysics Data System (ADS)

    Bubnicki, Z.

    2006-06-01

    The paper is concerned with a class of uncertain systems described by relational knowledge representations with unknown parameters which are assumed to be values of uncertain variables characterized by a user in the form of certainty distributions. The first part presents the basic optimization problem consisting in finding the decision maximizing the certainty index that the requirement given by a user is satisfied. The main part is devoted to the description of the optimization problem with the given certainty threshold. It is shown how the approach presented in the paper may be applied to some problems for anticipatory systems.

  16. Robust Unit Commitment Considering Uncertain Demand Response

    DOE PAGES

    Liu, Guodong; Tomsovic, Kevin

    2014-09-28

    Although price responsive demand response has been widely accepted as playing an important role in the reliable and economic operation of power system, the real response from demand side can be highly uncertain due to limited understanding of consumers' response to pricing signals. To model the behavior of consumers, the price elasticity of demand has been explored and utilized in both research and real practice. However, the price elasticity of demand is not precisely known and may vary greatly with operating conditions and types of customers. To accommodate the uncertainty of demand response, alternative unit commitment methods robust to themore » uncertainty of the demand response require investigation. In this paper, a robust unit commitment model to minimize the generalized social cost is proposed for the optimal unit commitment decision taking into account uncertainty of the price elasticity of demand. By optimizing the worst case under proper robust level, the unit commitment solution of the proposed model is robust against all possible realizations of the modeled uncertain demand response. Numerical simulations on the IEEE Reliability Test System show the e ectiveness of the method. Finally, compared to unit commitment with deterministic price elasticity of demand, the proposed robust model can reduce the average Locational Marginal Prices (LMPs) as well as the price volatility.« less

  17. Robust Unit Commitment Considering Uncertain Demand Response

    SciTech Connect

    Liu, Guodong; Tomsovic, Kevin

    2014-09-28

    Although price responsive demand response has been widely accepted as playing an important role in the reliable and economic operation of power system, the real response from demand side can be highly uncertain due to limited understanding of consumers' response to pricing signals. To model the behavior of consumers, the price elasticity of demand has been explored and utilized in both research and real practice. However, the price elasticity of demand is not precisely known and may vary greatly with operating conditions and types of customers. To accommodate the uncertainty of demand response, alternative unit commitment methods robust to the uncertainty of the demand response require investigation. In this paper, a robust unit commitment model to minimize the generalized social cost is proposed for the optimal unit commitment decision taking into account uncertainty of the price elasticity of demand. By optimizing the worst case under proper robust level, the unit commitment solution of the proposed model is robust against all possible realizations of the modeled uncertain demand response. Numerical simulations on the IEEE Reliability Test System show the e ectiveness of the method. Finally, compared to unit commitment with deterministic price elasticity of demand, the proposed robust model can reduce the average Locational Marginal Prices (LMPs) as well as the price volatility.

  18. A Nonlinear Digital Control Solution for a DC/DC Power Converter

    NASA Technical Reports Server (NTRS)

    Zhu, Minshao

    2002-01-01

    A digital Nonlinear Proportional-Integral-Derivative (NPID) control algorithm was proposed to control a 1-kW, PWM, DC/DC, switching power converter. The NPID methodology is introduced and a practical hardware control solution is obtained. The design of the controller was completed using Matlab (trademark) Simulink, while the hardware-in-the-loop testing was performed using both the dSPACE (trademark) rapid prototyping system, and a stand-alone Texas Instruments (trademark) Digital Signal Processor (DSP)-based system. The final Nonlinear digital control algorithm was implemented and tested using the ED408043-1 Westinghouse DC-DC switching power converter. The NPID test results are discussed and compared to the results of a standard Proportional-Integral (PI) controller.

  19. A Nonlinear Digital Control Solution for a DC/DC Power Converter

    NASA Astrophysics Data System (ADS)

    Zhu, Minshao

    2002-02-01

    A digital Nonlinear Proportional-Integral-Derivative (NPID) control algorithm was proposed to control a 1-kW, PWM, DC/DC, switching power converter. The NPID methodology is introduced and a practical hardware control solution is obtained. The design of the controller was completed using Matlab (trademark) Simulink, while the hardware-in-the-loop testing was performed using both the dSPACE (trademark) rapid prototyping system, and a stand-alone Texas Instruments (trademark) Digital Signal Processor (DSP)-based system. The final Nonlinear digital control algorithm was implemented and tested using the ED408043-1 Westinghouse DC-DC switching power converter. The NPID test results are discussed and compared to the results of a standard Proportional-Integral (PI) controller.

  20. Lattice animals: dc=8 for trees

    NASA Astrophysics Data System (ADS)

    Ruskin, H. J.; Duarte, J. A. M. S.

    1982-09-01

    The asymptotic behavior of the total number of treelike clusters (lattice trees) on the hypercubic system is investigated for d>=4 by the method of series expansions. Interest centers on ascertaining the critical dimension, dc, at which the prefactor exponent θ attains its mean-field value. We present results for θ and for the cluster growth parameter λ for d=4 to 9. The λ values are close to within a few percent of those found for the general animal case. Results for θ have large uncertainties in the dimensions of interest, and the mean-field value is approached very gradually with d, so that the possibility of a lower value for dc cannot be completely discarded. Nevertheless, the available evidence suggests that dc=8 for lattice trees. This supports the findings of Lubensky and Isaacson in their recent work on lattice animals and dilute branched polymers.

  1. RISK D/C

    NASA Technical Reports Server (NTRS)

    Dias, W. C.

    1994-01-01

    RISK D/C is a prototype program which attempts to do program risk modeling for the Space Exploration Initiative (SEI) architectures proposed in the Synthesis Group Report. Risk assessment is made with respect to risk events, their probabilities, and the severities of potential results. The program allows risk mitigation strategies to be proposed for an exploration program architecture and to be ranked with respect to their effectiveness. RISK D/C allows for the fact that risk assessment in early planning phases is subjective. Although specific to the SEI in its present form, RISK D/C can be used as a framework for developing a risk assessment program for other specific uses. RISK D/C is organized into files, or stacks, of information, including the architecture, the hazard, and the risk event stacks. Although predefined, all stacks can be upgraded by a user. The architecture stack contains information concerning the general program alternatives, which are subsequently broken down into waypoints, missions, and mission phases. The hazard stack includes any background condition which could result in a risk event. A risk event is anything unfavorable that could happen during the course of a specific point within an architecture, and the risk event stack provides the probabilities, consequences, severities, and any mitigation strategies which could be used to reduce the risk of the event, and how much the risk is reduced. RISK D/C was developed for Macintosh series computers. It requires HyperCard 2.0 or later, as well as 2Mb of RAM and System 6.0.8 or later. A Macintosh II series computer is recommended due to speed concerns. The standard distribution medium for this package is one 3.5 inch 800K Macintosh format diskette. RISK D/C was developed in 1991 and is a copyrighted work with all copyright vested in NASA. Macintosh and HyperCard are trademarks of Apple Computer, Inc.

  2. 75 FR 23571 - Airworthiness Directives; McDonnell Douglas Corporation Model DC-10-10, DC-10-10F, DC-10-15, DC...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-04

    ... Corporation Model DC- 10-10, DC-10-10F, DC-10-15, DC-10-30, DC-10-30F (KC-10A and KDC-10), DC-10-40, DC-10-40F.... ACTION: Final rule. SUMMARY: We are adopting a new airworthiness directive (AD) for certain Model DC-10-10, DC-10-10F, DC-10-15, DC-10-30, DC-10-30F (KC-10A and KDC-10), DC-10-40,......

  3. DC Breakdown Experiments

    SciTech Connect

    Calatroni, S.; Descoeudres, A.; Levinsen, Y.; Taborelli, M.; Wuensch, W.

    2009-01-22

    In the context of the CLIC (Compact Linear Collider) project investigations of DC breakdown in ultra high vacuum are carried out in parallel with high power RF tests. From the point of view of saturation breakdown field the best material tested so far is stainless steel, followed by titanium. Copper shows a four times weaker breakdown field than stainless steel. The results indicate clearly that the breakdown events are initiated by field emission current and that the breakdown field is limited by the cathode. In analogy to RF, the breakdown probability has been measured in DC and the data show similar behaviour as a function of electric field.

  4. DC attenuation meter

    DOEpatents

    Hargrove, Douglas L.

    2004-09-14

    A portable, hand-held meter used to measure direct current (DC) attenuation in low impedance electrical signal cables and signal attenuators. A DC voltage is applied to the signal input of the cable and feedback to the control circuit through the signal cable and attenuators. The control circuit adjusts the applied voltage to the cable until the feedback voltage equals the reference voltage. The "units" of applied voltage required at the cable input is the system attenuation value of the cable and attenuators, which makes this meter unique. The meter may be used to calibrate data signal cables, attenuators, and cable-attenuator assemblies.

  5. Preparing for an uncertain climate. Volume 2

    SciTech Connect

    Not Available

    1993-10-01

    Climate change poses many potential problems for human and natural systems, and the long-term effects of climate change on these systems are becoming increasingly important in public policy. For example, international agreements were recently signed on both climate change and biodiversity. Recognizing the potential problems, Congress asked OTA to examine how the Nation can best prepare for an uncertain future climate. This assessment tackles the difficult tasks of assessing how natural and human systems may be affected by climate change and of evaluating the tools at our disposal to ease adaptation to a warmer climate. Volume 1 addresses coastal areas, water resources, and agriculture (PB--94-134640); volume 2 includes wetlands, preserved lands, and forests.

  6. DYLOS DC110

    EPA Science Inventory

    The Dylos DC1100 air quality monitor measures particulate matter (PM) to provide a continuous assessment of indoor air quality. The unit counts particles in two size ranges: large and small. According to the manufacturer, large particles have diameters between 2.5 and 10 micromet...

  7. DC arc weld starter

    DOEpatents

    Campiotti, Richard H.; Hopwood, James E.

    1990-01-01

    A system for starting an arc for welding uses three DC power supplies, a high voltage supply for initiating the arc, an intermediate voltage supply for sustaining the arc, and a low voltage welding supply directly connected across the gap after the high voltage supply is disconnected.

  8. Early Oscillation Detection for DC/DC Converter Fault Diagnosis

    NASA Technical Reports Server (NTRS)

    Wang, Bright L.

    2011-01-01

    The electrical power system of a spacecraft plays a very critical role for space mission success. Such a modern power system may contain numerous hybrid DC/DC converters both inside the power system electronics (PSE) units and onboard most of the flight electronics modules. One of the faulty conditions for DC/DC converter that poses serious threats to mission safety is the random occurrence of oscillation related to inherent instability characteristics of the DC/DC converters and design deficiency of the power systems. To ensure the highest reliability of the power system, oscillations in any form shall be promptly detected during part level testing, system integration tests, flight health monitoring, and on-board fault diagnosis. The popular gain/phase margin analysis method is capable of predicting stability levels of DC/DC converters, but it is limited only to verification of designs and to part-level testing on some of the models. This method has to inject noise signals into the control loop circuitry as required, thus, interrupts the DC/DC converter's normal operation and increases risks of degrading and damaging the flight unit. A novel technique to detect oscillations at early stage for flight hybrid DC/DC converters was developed.

  9. Robust design optimization with an uncertain model of a nonlinear vibro-impact electro-mechanical system

    NASA Astrophysics Data System (ADS)

    Lima, Roberta; Soize, Christian; Sampaio, Rubens

    2015-06-01

    In this paper, the robust design with an uncertain model of a vibro-impact electro-mechanical system is done. The electro-mechanical system is composed of a cart, whose motion is excited by a DC motor (motor with continuous current), and an embarked hammer into this cart. The hammer is connected to the cart by a nonlinear spring component and by a linear damper, so that a relative motion exists between them. A linear flexible barrier, placed outside of the cart, constrains the hammer movements. Due to the relative movement between the hammer and the barrier, impacts can occur between these two elements. The developed model of the system takes into account the influence of the DC motor in the dynamic behavior of the system. Some system parameters are uncertain, such as the stiffness and the damping coefficients of the flexible barrier. The objective of the paper is to perform an optimization of this electro-mechanical system with respect to design parameters (spring component, and barrier g) in order to maximize the impact power under the constraint that the electric power consumed by the DC motor is lower than a maximum value. This optimization is formulated in the framework of robust design due to the presence of uncertainties in the model. The set of nonlinear equations are presented, and an adapted time domain solver is developed. The stochastic nonlinear constrained design optimization problem is solved for different levels of uncertainties, and also for the deterministic case.

  10. Conservation planning with uncertain climate change projections.

    PubMed

    Kujala, Heini; Moilanen, Atte; Araújo, Miguel B; Cabeza, Mar

    2013-01-01

    Climate change is affecting biodiversity worldwide, but conservation responses are constrained by considerable uncertainty regarding the magnitude, rate and ecological consequences of expected climate change. Here we propose a framework to account for several sources of uncertainty in conservation prioritization. Within this framework we account for uncertainties arising from (i) species distributions that shift following climate change, (ii) basic connectivity requirements of species, (iii) alternative climate change scenarios and their impacts, (iv) in the modelling of species distributions, and (v) different levels of confidence about present and future. When future impacts of climate change are uncertain, robustness of decision-making can be improved by quantifying the risks and trade-offs associated with climate scenarios. Sensible prioritization that accounts simultaneously for the present and potential future distributions of species is achievable without overly jeopardising present-day conservation values. Doing so requires systematic treatment of uncertainties and testing of the sensitivity of results to assumptions about climate. We illustrate the proposed framework by identifying priority areas for amphibians and reptiles in Europe.

  11. Probabilistic Graph Layout for Uncertain Network Visualization.

    PubMed

    Schulz, Christoph; Nocaj, Arlind; Goertler, Jochen; Deussen, Oliver; Brandes, Ulrik; Weiskopf, Daniel

    2017-01-01

    We present a novel uncertain network visualization technique based on node-link diagrams. Nodes expand spatially in our probabilistic graph layout, depending on the underlying probability distributions of edges. The visualization is created by computing a two-dimensional graph embedding that combines samples from the probabilistic graph. A Monte Carlo process is used to decompose a probabilistic graph into its possible instances and to continue with our graph layout technique. Splatting and edge bundling are used to visualize point clouds and network topology. The results provide insights into probability distributions for the entire network-not only for individual nodes and edges. We validate our approach using three data sets that represent a wide range of network types: synthetic data, protein-protein interactions from the STRING database, and travel times extracted from Google Maps. Our approach reveals general limitations of the force-directed layout and allows the user to recognize that some nodes of the graph are at a specific position just by chance.

  12. Learning to learn about uncertain feedback.

    PubMed

    Faraut, Maïlys C M; Procyk, Emmanuel; Wilson, Charles R E

    2016-02-01

    Unexpected outcomes can reflect noise in the environment or a change in the current rules. We should ignore noise but shift strategy after rule changes. How we learn to do this is unclear, but one possibility is that it relies on learning to learn in uncertain environments. We propose that acquisition of latent task structure during learning to learn, even when not necessary, is crucial. We report results consistent with this hypothesis. Macaque monkeys acquired adaptive responses to feedback while learning to learn serial stimulus-response associations with probabilistic feedback. Monkeys learned well, decreasing their errors to criterion, but they also developed an apparently nonadaptive reactivity to unexpected stochastic feedback, even though that unexpected feedback never predicted problem switch. This surprising learning trajectory permitted the same monkeys, naïve to relearning about previously learned stimuli, to transfer to a task of stimulus-response remapping at immediately asymptotic levels. Our results suggest that learning new problems in a stochastic environment promotes the acquisition of performance rules from latent task structure, providing behavioral flexibility. Learning to learn in a probabilistic and volatile environment thus appears to induce latent learning that may be beneficial to flexible cognition.

  13. Free Vibration of Uncertain Unsymmetrically Laminated Beams

    NASA Technical Reports Server (NTRS)

    Kapania, Rakesh K.; Goyal, Vijay K.

    2001-01-01

    Monte Carlo Simulation and Stochastic FEA are used to predict randomness in the free vibration response of thin unsymmetrically laminated beams. For the present study, it is assumed that randomness in the response is only caused by uncertainties in the ply orientations. The ply orientations may become random or uncertain during the manufacturing process. A new 16-dof beam element, based on the first-order shear deformation beam theory, is used to study the stochastic nature of the natural frequencies. Using variational principles, the element stiffness matrix and mass matrix are obtained through analytical integration. Using a random sequence a large data set is generated, containing possible random ply-orientations. This data is assumed to be symmetric. The stochastic-based finite element model for free vibrations predicts the relation between the randomness in fundamental natural frequencies and the randomness in ply-orientation. The sensitivity derivatives are calculated numerically through an exact formulation. The squared fundamental natural frequencies are expressed in terms of deterministic and probabilistic quantities, allowing to determine how sensitive they are to variations in ply angles. The predicted mean-valued fundamental natural frequency squared and the variance of the present model are in good agreement with Monte Carlo Simulation. Results, also, show that variations between plus or minus 5 degrees in ply-angles can affect free vibration response of unsymmetrically and symmetrically laminated beams.

  14. Sequential Auctions in Uncertain Information Settings

    NASA Astrophysics Data System (ADS)

    Fatima, Shaheen; Wooldridge, Michael; Jennings, Nicholas R.

    This paper analyzes sequential auctions for private value objects using second-price sealed-bid rules. Now, the equilibrium bids for such auctions depend on the information uncertainty of the bidders. Specifically, there are three key auction parameters that the bidders could be uncertain about: the valuations of the objects for sale, the number of objects for sale, and the number of participating bidders. We analyse the bidding behaviour for each of these three sources of uncertainty. For each setting, we first find the equilibrium bidding strategies for the individual auctions that comprise a series. Then we analyze the effect of these uncertainties on the computational and economic properties of the equilibrium solution. The former analysis is essential if we want to use software agents to bid on our behalf. The latter is essential because both the auctioneer and the bidders want to know how these uncertainties affect their profits. Thus we compare the outcomes for these settings from the perspective of the bidders (i.e., in terms of their profits), from the perspective of the auctioneer (i.e., in terms of his revenue), and from a global perspective (i.e., in terms of auction efficiency).

  15. Learning to learn about uncertain feedback

    PubMed Central

    Procyk, Emmanuel

    2016-01-01

    Unexpected outcomes can reflect noise in the environment or a change in the current rules. We should ignore noise but shift strategy after rule changes. How we learn to do this is unclear, but one possibility is that it relies on learning to learn in uncertain environments. We propose that acquisition of latent task structure during learning to learn, even when not necessary, is crucial. We report results consistent with this hypothesis. Macaque monkeys acquired adaptive responses to feedback while learning to learn serial stimulus-response associations with probabilistic feedback. Monkeys learned well, decreasing their errors to criterion, but they also developed an apparently nonadaptive reactivity to unexpected stochastic feedback, even though that unexpected feedback never predicted problem switch. This surprising learning trajectory permitted the same monkeys, naïve to relearning about previously learned stimuli, to transfer to a task of stimulus-response remapping at immediately asymptotic levels. Our results suggest that learning new problems in a stochastic environment promotes the acquisition of performance rules from latent task structure, providing behavioral flexibility. Learning to learn in a probabilistic and volatile environment thus appears to induce latent learning that may be beneficial to flexible cognition. PMID:26787780

  16. AC/DC converter

    NASA Astrophysics Data System (ADS)

    Jain, Praveen K.

    1992-08-01

    In a system such as a 20 kHz space station primary electrical power distribution system, power conversion from AC to DC is required. Some of the basic requirements for this conversion are high efficiency, light weight and small volume, regulated output voltage, close to unity input power factor, distortionless input current, soft-starting, low electromagnetic interference, and high reliability. An AC-to-DC converter is disclosed which satisfies the main design objectives of such converters for use in space. The converter of the invention comprises an input transformer, a resonant network, a current controller, a diode rectifier, and an output filter. The input transformer is for connection to a single phase, high frequency, sinusoidal waveform AC voltage source and provides a matching voltage isolating from the AC source. The resonant network converts this voltage to a sinusoidal, high frequency bidirectional current output, which is received by the current controller to provide the desired output current. The diode rectifier is connected in parallel with the current controller to convert the bidirectional current into a unidirectional current output. The output filter is connected to the rectifier to provide an essentially ripple-free, substantially constant voltage DC output.

  17. 76 FR 18022 - Airworthiness Directives; The Boeing Company Model DC-9-14, DC-9-15, and DC-9-15F Airplanes; and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-01

    ... Model DC-9-14, DC-9- 15, and DC-9-15F Airplanes; and DC-9-20, DC-9-30, DC-9-40, and DC-9-50 Series..., Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590. FOR FURTHER INFORMATION CONTACT...) This AD applies to The Boeing Company Model DC-9-14, DC-9- 15, DC-9-15F, DC-9-21, DC-9-31,......

  18. 75 FR 47242 - Airworthiness Directives; McDonnell Douglas Corporation Model DC-9-14, DC-9-15, and DC-9-15F...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-05

    ... Corporation Model DC- 9-14, DC-9-15, and DC-9-15F Airplanes; and Model DC-9-20, DC-9-30, DC- 9-40, and DC-9-50... airworthiness directive (AD) that applies to certain Model DC-9-14 and DC-9-15 airplanes; and Model DC-9-20, DC-9-30, DC-9-40, and DC-9-50 series airplanes. The existing AD currently......

  19. Isolated Bidirectional DC-DC Converter for Hybrid Electric Vehicle Application

    DTIC Science & Technology

    2006-06-13

    34Approved for public release: distribution is unlimited" Isolated Bidirectional DC-DC Converter for Hybrid Electric Vehicle Applications Sonya...requirements for DC-DC converters for electric and hybrid vehicles . This paper introduces a bidirectional, isolated DC-DC converter for medium power...the design and build of a medium power DC-DC converter . Key words: Power Converter , DC-DC, Hybrid Electric Vehicle , Battery, Galvanically Isolation

  20. Population, resources, environment: an uncertain future.

    PubMed

    Repetto, R

    1987-07-01

    This issue analyzes the economic and environmental consequences of rapid population growth in developing countries (LDC), the population decline in developed countries, the limits that life on a finite planet impose on economic and demographic expansion and progress, and the proper governmental response to promote the welfare of its current and future citizens. The links between population growth, resource use, and environmental quality are too complex to permit straightforward generalizations about direct causal relationships. However, rapid population growth has increased the number of poor people in LDC, thus contributing to degradation of the environment and the renewable resources of land, water, and nonhuman species on which humans depend. Demands of the rich industrial countries have also generated environmental pressures and have been foremost in consumption of the nonrenewable resources of fossil fuels, metals, and nonmetallic minerals. On the other hand, population and economic growth have also stimulated technological and management changes that help supply and use resources more effectively. Wide variations in the possible ultimate size of world population and accelerating technological change make future interrelationships of population, resources, and the environment uncertain as well as complex. Those interrelationships are mediated largely by government policies. Responsible governments can bring about a sustainable balance in the population/resource/environment equation by adopting population and development policies that experience has shown could reduce future population numbers in LDC below the additional 5 billion indicated in current UN medium projections. This coupled with proven management programs in both LDC and developed countries could brake and reverse the depletion and degradation of natural resources.

  1. (Uncertain) Carbonyl Sulfide Plant Fluxes Spatially Constrain (Even More Uncertain) CO2 GPP

    NASA Astrophysics Data System (ADS)

    Hilton, T. W.; Whelan, M.; Kulkarni, S.; Zumkehr, A. L.; Berry, J. A.; Campbell, J. E.

    2015-12-01

    With predictions of future terrestrial carbon dioxide (CO2)gross primary productivity (GPP) remaining stubbornly uncertain,ecosystem carbonyl sulfide (COS) fluxes provide an independent source ofinformation that may be able to reduce that uncertainty. Several openquestions must be addressed before COS may be applied widely as a GPPtracer. Here we employ an atmospheric chemistry and transport model(STEM) and airborne atmospheric COS concentration observations todemonstrate that COS plant uptake spatially constrains CO2 GPP even whenaccounting for soil COS flux uncertainty and COS leaf-scale relativeuptake variability and uncertainty.

  2. Complete prewetting

    NASA Astrophysics Data System (ADS)

    Yatsyshin, P.; Parry, A. O.; Kalliadasis, S.

    2016-07-01

    We study continuous interfacial transitions, analagous to two-dimensional complete wetting, associated with the first-order prewetting line, which can occur on steps, patterned walls, grooves and wedges, and which are sensitive to both the range of the intermolecular forces and interfacial fluctuation effects. These transitions compete with wetting, filling and condensation producing very rich phase diagrams even for relatively simple prototypical geometries. Using microscopic classical density functional theory to model systems with realistic Lennard-Jones fluid-fluid and fluid-substrate intermolecular potentials, we compute mean-field fluid density profiles, adsorption isotherms and phase diagrams for a variety of confining geometries.

  3. Auxiliary resonant DC tank converter

    DOEpatents

    Peng, Fang Z.

    2000-01-01

    An auxiliary resonant dc tank (ARDCT) converter is provided for achieving soft-switching in a power converter. An ARDCT circuit is coupled directly across a dc bus to the inverter to generate a resonant dc bus voltage, including upper and lower resonant capacitors connected in series as a resonant leg, first and second dc tank capacitors connected in series as a tank leg, and an auxiliary resonant circuit comprising a series combination of a resonant inductor and a pair of auxiliary switching devices. The ARDCT circuit further includes first clamping means for holding the resonant dc bus voltage to the dc tank voltage of the tank leg, and second clamping means for clamping the resonant dc bus voltage to zero during a resonant period. The ARDCT circuit resonantly brings the dc bus voltage to zero in order to provide a zero-voltage switching opportunity for the inverter, then quickly rebounds the dc bus voltage back to the dc tank voltage after the inverter changes state. The auxiliary switching devices are turned on and off under zero-current conditions. The ARDCT circuit only absorbs ripples of the inverter dc bus current, thus having less current stress. In addition, since the ARDCT circuit is coupled in parallel with the dc power supply and the inverter for merely assisting soft-switching of the inverter without participating in real dc power transmission and power conversion, malfunction and failure of the tank circuit will not affect the functional operation of the inverter; thus a highly reliable converter system is expected.

  4. Learning accurate very fast decision trees from uncertain data streams

    NASA Astrophysics Data System (ADS)

    Liang, Chunquan; Zhang, Yang; Shi, Peng; Hu, Zhengguo

    2015-12-01

    Most existing works on data stream classification assume the streaming data is precise and definite. Such assumption, however, does not always hold in practice, since data uncertainty is ubiquitous in data stream applications due to imprecise measurement, missing values, privacy protection, etc. The goal of this paper is to learn accurate decision tree models from uncertain data streams for classification analysis. On the basis of very fast decision tree (VFDT) algorithms, we proposed an algorithm for constructing an uncertain VFDT tree with classifiers at tree leaves (uVFDTc). The uVFDTc algorithm can exploit uncertain information effectively and efficiently in both the learning and the classification phases. In the learning phase, it uses Hoeffding bound theory to learn from uncertain data streams and yield fast and reasonable decision trees. In the classification phase, at tree leaves it uses uncertain naive Bayes (UNB) classifiers to improve the classification performance. Experimental results on both synthetic and real-life datasets demonstrate the strong ability of uVFDTc to classify uncertain data streams. The use of UNB at tree leaves has improved the performance of uVFDTc, especially the any-time property, the benefit of exploiting uncertain information, and the robustness against uncertainty.

  5. DC Cable for Railway

    NASA Astrophysics Data System (ADS)

    Tomita, Masaru

    The development of a superconducting cable for railways has commenced, assuming that a DC transmission cable will be used for electric trains. The cable has been fabricated based on the results of current testing of a superconducting wire, and various evaluation tests have been performed to determine the characteristics of the cable. A superconducting transmission cable having zero electrical resistance and suitable for railway use is expected to enhance regeneration efficiency, reduce power losses, achieve load leveling and integration of sub-stations, and reduce rail potential.

  6. Analysis of self-oscillating dc-to-dc converters

    NASA Technical Reports Server (NTRS)

    Burger, P.

    1974-01-01

    The basic operational characteristics of dc-to-dc converters are analyzed along with the basic physical characteristics of power converters. A simple class of dc-to-dc power converters are chosen which could satisfy any set of operating requirements, and three different controlling methods in this class are described in detail. Necessary conditions for the stability of these converters are measured through analog computer simulation whose curves are related to other operational characteristics, such as ripple and regulation. Further research is suggested for the solution of absolute stability and efficient physical design of this class of power converters.

  7. Multiple high voltage output DC-to-DC power converter

    NASA Technical Reports Server (NTRS)

    Cronin, Donald L. (Inventor); Farber, Bertrand F. (Inventor); Gehm, Hartmut K. (Inventor); Goldin, Daniel S. (Inventor)

    1977-01-01

    Disclosed is a multiple output DC-to-DC converter. The DC input power is filtered and passed through a chopper preregulator. The chopper output is then passed through a current source inverter controlled by a squarewave generator. The resultant AC is passed through the primary winding of a transformer, with high voltages induced in a plurality of secondary windings. The high voltage secondary outputs are each solid-state rectified for passage to individual output loads. Multiple feedback loops control the operation of the chopper preregulator, one being responsive to the current through the primary winding and another responsive to the DC voltage level at a selected output.

  8. Cluster synchronization between uncertain networks with different dynamics

    NASA Astrophysics Data System (ADS)

    Lü, Ling; Li, Chengren; Bai, Suyuan; Gao, Liyu; Ge, Lianjun; Han, Changhui

    2017-03-01

    We propose a new technique for the cluster synchronization between uncertain networks with different dynamics. Based on the Lyapunov theorem and Lipschitz condition, the network controllers and the identification laws of uncertain parameters are designed, and they are efficiently used to achieve the cluster synchronization and the identification of uncertain parameters. Particularly in our work, the dynamics of nodes in different clusters can be different. And there are not any limitations for the division of the clusters, the number of nodes in each cluster and the connections between nodes.

  9. Improved DC Gun Insulator

    SciTech Connect

    M.L. Neubauer, K.B. Beard, R. Sah, C. Hernandez-Garcia, G. Neil

    2009-05-01

    Many user facilities such as synchrotron light sources and free electron lasers require accelerating structures that support electric fields of 10-100 MV/m, especially at the start of the accelerator chain where ceramic insulators are used for very high gradient DC guns. These insulators are difficult to manufacture, require long commissioning times, and have poor reliability, in part because energetic electrons bury themselves in the ceramic, creating a buildup of charge and causing eventual puncture. A novel ceramic manufacturing process is proposed. It will incorporate bulk resistivity in the region where it is needed to bleed off accumulated charge caused by highly energetic electrons. This process will be optimized to provide an appropriate gradient in bulk resistivity from the vacuum side to the air side of the HV standoff ceramic cylinder. A computer model will be used to determine the optimum cylinder dimensions and required resistivity gradient for an example RF gun application. A ceramic material example with resistivity gradient appropriate for use as a DC gun insulator will be fabricated by glazing using doping compounds and tested.

  10. Use of microcomputers for inventory management with uncertain demand

    SciTech Connect

    Meadows, B F

    1984-01-01

    This paper describes how a microcomputer is used for analysis of inventory trends to optimize inventory investment and customer service level in a distribution environment with uncertain demand, and to support an inventory subsystem resident on a main computer.

  11. 17. Photocopy of photograph (source uncertain; probably the Bucks County ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    17. Photocopy of photograph (source uncertain; probably the Bucks County Historical Society) ca. 1913, photographer unknown SHOWING 1904 SOCIETY HEADQUARTERS AND THE EARLY PHASES OF CONSTRUCTION ON MERCER'S ADDITION - Mercer Museum, Pine & Ashland Streets, Doylestown, Bucks County, PA

  12. SCM Handbooks for dc-to-dc Converters

    NASA Technical Reports Server (NTRS)

    Lee, F.; Mohmoud, M.; Yu, Y.

    1984-01-01

    Two documents aid in design of control modules for dc-to-dc converters. Features of SCM include: Adaptive stability, power component stress limiting, implementation of various control laws, unified design approach. Analysis and quidelines contained in handbooks enable engineer to design SCM circuit and confidently predict resulting overall performance.

  13. Efficient Design in a DC to DC Converter Unit

    NASA Technical Reports Server (NTRS)

    Bruemmer, Joel E.; Williams, Fitch R.; Schmitz, Gregory V.

    2002-01-01

    Space Flight hardware requires high power conversion efficiencies due to limited power availability and weight penalties of cooling systems. The International Space Station (ISS) Electric Power System (EPS) DC-DC Converter Unit (DDCU) power converter is no exception. This paper explores the design methods and tradeoffs that were utilized to accomplish high efficiency in the DDCU. An isolating DC to DC converter was selected for the ISS power system because of requirements for separate primary and secondary grounds and for a well-regulated secondary output voltage derived from a widely varying input voltage. A flyback-current-fed push-pull topology or improved Weinberg circuit was chosen for this converter because of its potential for high efficiency and reliability. To enhance efficiency, a non-dissipative snubber circuit for the very-low-Rds-on Field Effect Transistors (FETs) was utilized, redistributing the energy that could be wasted during the switching cycle of the power FETs. A unique, low-impedance connection system was utilized to improve contact resistance over a bolted connection. For improved consistency in performance and to lower internal wiring inductance and losses a planar bus system is employed. All of these choices contributed to the design of a 6.25 KW regulated dc to dc converter that is 95 percent efficient. The methodology used in the design of this DC to DC Converter Unit may be directly applicable to other systems that require a conservative approach to efficient power conversion and distribution.

  14. Dc-To-Dc Converter Uses Reverse Conduction Of MOSFET's

    NASA Technical Reports Server (NTRS)

    Gruber, Robert P.; Gott, Robert W.

    1991-01-01

    In modified high-power, phase-controlled, full-bridge, pulse-width-modulated dc-to-dc converters, switching devices power metal oxide/semiconductor field-effect transistors (MOSFET's). Decreases dissipation of power during switching by eliminating approximately 0.7-V forward voltage drop in anti-parallel diodes. Energy-conversion efficiency increased.

  15. First experimental results from DC/DC and AC/DC plasma-based power transformers

    NASA Astrophysics Data System (ADS)

    McEvoy, Aaron; Gibson, William; Nebel, Richard

    2016-10-01

    A plasma-based power transformer has been built and operated in both DC/DC and AC/DC mode. The proprietary Tibbar Plasma Technologies, Inc. transformer design consists of two cylindrically symmetric helical primary electrodes surrounding a low temperature plasma within which a secondary axial current is generated. Initial experimental results have compared well with simulations and moderate conversion efficiencies have been observed. A new proprietary device is currently being constructed that will utilize 3-phase 480 VAC input to achieve higher conversion efficiency and output power. A description of the apparatus and several potential applications will be presented along with preliminary experimental data demonstrating the DC/DC and AC/DC conversion processes. Work performed under ARPA-E contract DE-AR0000677.

  16. Preventing Exploits Against Software of Uncertain Provenance (PEASOUP)

    DTIC Science & Technology

    2015-05-01

    results of the research and development of PEASOUP (Preventing Exploits Against Software of Uncertain Provenance), a technology that enables the safe...Preventing Exploits Against Software of Uncertain Provenance), a technology that enables the safe execution of software executables. PEASOUP...Products and Transferable Technology 5 2.2 Use of Third-Party COTS Products 7 2.3 Overview of the Technical Approach and Plan 8 2.4 2.4.1 The (Offline

  17. Synchronization between uncertain nonidentical networks with quantum chaotic behavior

    NASA Astrophysics Data System (ADS)

    Li, Wenlin; Li, Chong; Song, Heshan

    2016-11-01

    Synchronization between uncertain nonidentical networks with quantum chaotic behavior is researched. The identification laws of unknown parameters in state equations of network nodes, the adaptive laws of configuration matrix elements and outer coupling strengths are determined based on Lyapunov theorem. The conditions of realizing synchronization between uncertain nonidentical networks are discussed and obtained. Further, Jaynes-Cummings model in physics are taken as the nodes of two networks and simulation results show that the synchronization performance between networks is very stable.

  18. Addressing an Uncertain Future Using Scenario Analysis

    SciTech Connect

    Siddiqui, Afzal S.; Marnay, Chris

    2006-12-15

    The Office of Energy Efficiency and Renewable Energy (EERE) has had a longstanding goal of introducing uncertainty into the analysis it routinely conducts in compliance with the Government Performance and Results Act (GPRA) and for strategic management purposes. The need to introduce some treatment of uncertainty arises both because it would be good general management practice, and because intuitively many of the technologies under development by EERE have a considerable advantage in an uncertain world. For example, an expected kWh output from a wind generator in a future year, which is not exposed to volatile and unpredictable fuel prices, should be truly worth more than an equivalent kWh from an alternative fossil fuel fired technology. Indeed, analysts have attempted to measure this value by comparing the prices observed in fixed-price natural gas contracts compared to ones in which buyers are exposed to market prices (see Bolinger, Wiser, and Golove and (2004)). In addition to the routine reasons for exploring uncertainty given above, the history of energy markets appears to have exhibited infrequent, but troubling, regime shifts, i.e., historic turning points at which the center of gravity or fundamental nature of the system appears to have abruptly shifted. Figure 1 below shows an estimate of how the history of natural gas fired generating costs has evolved over the last three decades. The costs shown incorporate both the well-head gas price and an estimate of how improving generation technology has gradually tended to lower costs. The purpose of this paper is to explore scenario analysis as a method for introducing uncertainty into EERE's forecasting in a manner consistent with the preceding observation. The two questions are how could it be done, and what is its academic basis, if any. Despite the interest in uncertainty methods, applying them poses some major hurdles because of the heavy reliance of EERE on forecasting tools that are deterministic in

  19. Early Oscillation Detection Technique for Hybrid DC/DC Converters

    NASA Technical Reports Server (NTRS)

    Wang, Bright L.

    2011-01-01

    Oscillation or instability is a situation that must be avoided for reliable hybrid DC/DC converters. A real-time electronics measurement technique was developed to detect catastrophic oscillations at early stages for hybrid DC/DC converters. It is capable of identifying low-level oscillation and determining the degree of the oscillation at a unique frequency for every individual model of the converters without disturbing their normal operations. This technique is specially developed for space-used hybrid DC/DC converters, but it is also suitable for most of commercial and military switching-mode power supplies. This is a weak-electronic-signal detection technique to detect hybrid DC/DC converter oscillation presented as a specific noise signal at power input pins. It is based on principles of feedback control loop oscillation and RF signal modulations, and is realized by using signal power spectral analysis. On the power spectrum, a channel power amplitude at characteristic frequency (CPcf) and a channel power amplitude at switching frequency (CPsw) are chosen as oscillation level indicators. If the converter is stable, the CPcf is a very small pulse and the CPsw is a larger, clear, single pulse. At early stage of oscillation, the CPcf increases to a certain level and the CPsw shows a small pair of sideband pulses around it. If the converter oscillates, the CPcf reaches to a higher level and the CPsw shows more high-level sideband pulses. A comprehensive stability index (CSI) is adopted as a quantitative measure to accurately assign a degree of stability to a specific DC/DC converter. The CSI is a ratio of normal and abnormal power spectral density, and can be calculated using specified and measured CPcf and CPsw data. The novel and unique feature of this technique is the use of power channel amplitudes at characteristic frequency and switching frequency to evaluate stability and identify oscillations at an early stage without interfering with a DC/DC converter s

  20. Neural basis of uncertain cue processing in trait anxiety

    PubMed Central

    Zhang, Meng; Ma, Chao; Luo, Yanyan; Li, Ji; Li, Qingwei; Liu, Yijun; Ding, Cody; Qiu, Jiang

    2016-01-01

    Individuals with high trait anxiety form a non-clinical group with a predisposition for an anxiety-related bias in emotional and cognitive processing that is considered by some to be a prerequisite for psychiatric disorders. Anxious individuals tend to experience more worry under uncertainty, and processing uncertain information is an important, but often overlooked factor in anxiety. So, we decided to explore the brain correlates of processing uncertain information in individuals with high trait anxiety using the learn-test paradigm. Behaviorally, the percentages on memory test and the likelihood ratios of identifying novel stimuli under uncertainty were similar to the certain fear condition, but different from the certain neutral condition. The brain results showed that the visual cortex, bilateral fusiform gyrus, and right parahippocampal gyrus were active during the processing of uncertain cues. Moreover, we found that trait anxiety was positively correlated with the BOLD signal of the right parahippocampal gyrus during the processing of uncertain cues. No significant results were found in the amygdala during uncertain cue processing. These results suggest that memory retrieval is associated with uncertain cue processing, which is underpinned by over-activation of the right parahippocampal gyrus, in individuals with high trait anxiety. PMID:26892030

  1. A DC Transformer

    NASA Technical Reports Server (NTRS)

    Youngquist, Robert C.; Ihlefeld, Curtis M.; Starr, Stanley O.

    2013-01-01

    A component level dc transformer is described in which no alternating currents or voltages are present. It operates by combining features of a homopolar motor and a homopolar generator, both de devices, such that the output voltage of a de power supply can be stepped up (or down) with a corresponding step down (or up) in current. The basic theory for this device is developed, performance predictions are made, and the results from a small prototype are presented. Based on demonstrated technology in the literature, this de transformer should be scalable to low megawatt levels, but it is more suited to high current than high voltage applications. Significant development would be required before it could achieve the kilovolt levels needed for de power transmission.

  2. Experience from design, prototyping and production of a DC-DC conversion powering scheme for the CMS Phase-1 Pixel Upgrade

    NASA Astrophysics Data System (ADS)

    Feld, Lutz; Karpinski, Waclaw; Klein, Katja; Lipinski, Martin; Preuten, Marius; Rauch, Max; Schmitz, Stefan; Wlochal, Michael

    2017-02-01

    The CMS pixel detector will be replaced during the technical stop 2016/2017. To allow the new pixel detector to be powered with the legacy cable plant and power supplies, a novel powering scheme based on DC-DC conversion will be employed. After the successful conclusion of an extensive development and prototyping phase, mass production of 1800 DC-DC converters as well as motherboards and other power PCBs has now been completed. This contribution reviews the lessons learned from the development of the power system for the Phase-1 pixel detector, and summarizes the experience gained from the production phase.

  3. Triple voltage dc-to-dc converter and method

    DOEpatents

    Su, Gui-Jia

    2008-08-05

    A circuit and method of providing three dc voltage buses and transforming power between a low voltage dc converter and a high voltage dc converter, by coupling a primary dc power circuit and a secondary dc power circuit through an isolation transformer; providing the gating signals to power semiconductor switches in the primary and secondary circuits to control power flow between the primary and secondary circuits and by controlling a phase shift between the primary voltage and the secondary voltage. The primary dc power circuit and the secondary dc power circuit each further comprising at least two tank capacitances arranged in series as a tank leg, at least two resonant switching devices arranged in series with each other and arranged in parallel with the tank leg, and at least one voltage source arranged in parallel with the tank leg and the resonant switching devices, said resonant switching devices including power semiconductor switches that are operated by gating signals. Additional embodiments having a center-tapped battery on the low voltage side and a plurality of modules on both the low voltage side and the high voltage side are also disclosed for the purpose of reducing ripple current and for reducing the size of the components.

  4. Bi-Directional DC-DC Converter for PHEV Applications

    SciTech Connect

    Abas Goodarzi

    2011-01-31

    Plug-In Hybrid Electric Vehicles (PHEV) require high power density energy storage system (ESS) for hybrid operation and high energy density ESS for Electric Vehicle (EV) mode range. However, ESS technologies to maximize power density and energy density simultaneously are not commercially feasible. The use of bi-directional DC-DC converter allows use of multiple energy storage, and the flexible DC-link voltages can enhance the system efficiency and reduce component sizing. This will improve fuel consumption, increase the EV mode range, reduce the total weight, reduce battery initial and life cycle cost, and provide flexibility in system design.

  5. GaN Microwave DC-DC Converters

    NASA Astrophysics Data System (ADS)

    Ramos Franco, Ignacio

    Increasing the operating frequency of switching converters can have a direct impact in the miniaturization and integration of power converters. The size of energy-storage passive components and the difficulty to integrate them with the rest of the circuitry is a major challenge in the development of a fully integrated power supply on a chip. The work presented in this thesis attempts to address some of the difficulties encountered in the design of high-frequency converters by applying concepts and techniques usually used in the design of high-efficiency power amplifiers and high-efficiency rectifiers at microwave frequencies. The main focus is in the analysis, design, and characterization of dc-dc converters operating at microwave frequencies in the low gigahertz range. The concept of PA-rectifier duality, where a high-efficiency power amplifier operates as a high-efficiency rectifier is investigated through non-linear simulations and experimentally validated. Additionally, the concept of a self-synchronous rectifier, where a transistor rectifier operates synchronously without the need of a RF source or driver is demonstrated. A theoretical analysis of a class-E self-synchronous rectifier is presented and validated through non-linear simulations and experiments. Two GaN class-E2 dc-dc converters operating at a switching frequency of 1 and 1.2 GHz are demonstrated. The converters achieve 80 % and 75 % dc-dc efficiency respectively and are among the highest-frequency and highest-efficiency reported in the literature. The application of the concepts established in the analysis of a self-synchronous rectifier to a power amplifier culminated in the development of an oscillating, self-synchronous class-E 2 dc-dc converter. Finally, a proof-of-concept fully integrated GaN MMIC class-E 2 dc-dc converter switching at 4.6 GHz is demonstrated for the first time to the best of our knowledge. The 3.8 mm x 2.6 mm chip contains distributed inductors and does not require any

  6. MAGDM linear-programming models with distinct uncertain preference structures.

    PubMed

    Xu, Zeshui S; Chen, Jian

    2008-10-01

    Group decision making with preference information on alternatives is an interesting and important research topic which has been receiving more and more attention in recent years. The purpose of this paper is to investigate multiple-attribute group decision-making (MAGDM) problems with distinct uncertain preference structures. We develop some linear-programming models for dealing with the MAGDM problems, where the information about attribute weights is incomplete, and the decision makers have their preferences on alternatives. The provided preference information can be represented in the following three distinct uncertain preference structures: 1) interval utility values; 2) interval fuzzy preference relations; and 3) interval multiplicative preference relations. We first establish some linear-programming models based on decision matrix and each of the distinct uncertain preference structures and, then, develop some linear-programming models to integrate all three structures of subjective uncertain preference information provided by the decision makers and the objective information depicted in the decision matrix. Furthermore, we propose a simple and straightforward approach in ranking and selecting the given alternatives. It is worth pointing out that the developed models can also be used to deal with the situations where the three distinct uncertain preference structures are reduced to the traditional ones, i.e., utility values, fuzzy preference relations, and multiplicative preference relations. Finally, we use a practical example to illustrate in detail the calculation process of the developed approach.

  7. DC-Compensated Current Transformer.

    PubMed

    Ripka, Pavel; Draxler, Karel; Styblíková, Renata

    2016-01-20

    Instrument current transformers (CTs) measure AC currents. The DC component in the measured current can saturate the transformer and cause gross error. We use fluxgate detection and digital feedback compensation of the DC flux to suppress the overall error to 0.15%. This concept can be used not only for high-end CTs with a nanocrystalline core, but it also works for low-cost CTs with FeSi cores. The method described here allows simultaneous measurements of the DC current component.

  8. Digital Control Technologies for Modular DC-DC Converters

    NASA Technical Reports Server (NTRS)

    Button, Robert M.; Kascak, Peter E.; Lebron-Velilla, Ramon

    2002-01-01

    Recent trends in aerospace Power Management and Distribution (PMAD) systems focus on using commercial off-the-shelf (COTS) components as standard building blocks. This move to more modular designs has been driven by a desire to reduce costs and development times, but is also due to the impressive power density and efficiency numbers achieved by today's commercial DC-DC converters. However, the PMAD designer quickly learns of the hidden "costs" of using COTS converters. The most significant cost is the required addition of external input filters to meet strict electromagnetic interference (MIAMI) requirements for space systems. In fact, the high power density numbers achieved by the commercial manufacturers are greatly due to the lack of necessary input filters included in the COTS module. The NASA Glenn Research Center is currently pursuing a digital control technology that addresses this problem with modular DC-DC converters. This paper presents the digital control technologies that have been developed to greatly reduce the input filter requirements for paralleled, modular DC-DC converters. Initial test result show that the input filter's inductor size was reduced by 75 percent, and the capacitor size was reduced by 94 percent while maintaining the same power quality specifications.

  9. An artificial bee colony algorithm for uncertain portfolio selection.

    PubMed

    Chen, Wei

    2014-01-01

    Portfolio selection is an important issue for researchers and practitioners. In this paper, under the assumption that security returns are given by experts' evaluations rather than historical data, we discuss the portfolio adjusting problem which takes transaction costs and diversification degree of portfolio into consideration. Uncertain variables are employed to describe the security returns. In the proposed mean-variance-entropy model, the uncertain mean value of the return is used to measure investment return, the uncertain variance of the return is used to measure investment risk, and the entropy is used to measure diversification degree of portfolio. In order to solve the proposed model, a modified artificial bee colony (ABC) algorithm is designed. Finally, a numerical example is given to illustrate the modelling idea and the effectiveness of the proposed algorithm.

  10. Uncertain behaviours of integrated circuits improve computational performance

    PubMed Central

    Yoshimura, Chihiro; Yamaoka, Masanao; Hayashi, Masato; Okuyama, Takuya; Aoki, Hidetaka; Kawarabayashi, Ken-ichi; Mizuno, Hiroyuki

    2015-01-01

    Improvements to the performance of conventional computers have mainly been achieved through semiconductor scaling; however, scaling is reaching its limitations. Natural phenomena, such as quantum superposition and stochastic resonance, have been introduced into new computing paradigms to improve performance beyond these limitations. Here, we explain that the uncertain behaviours of devices due to semiconductor scaling can improve the performance of computers. We prototyped an integrated circuit by performing a ground-state search of the Ising model. The bit errors of memory cell devices holding the current state of search occur probabilistically by inserting fluctuations into dynamic device characteristics, which will be actualised in the future to the chip. As a result, we observed more improvements in solution accuracy than that without fluctuations. Although the uncertain behaviours of devices had been intended to be eliminated in conventional devices, we demonstrate that uncertain behaviours has become the key to improving computational performance. PMID:26586362

  11. Multiple Choice Neurodynamical Model of the Uncertain Option Task.

    PubMed

    Insabato, Andrea; Pannunzi, Mario; Deco, Gustavo

    2017-01-01

    The uncertain option task has been recently adopted to investigate the neural systems underlying the decision confidence. Latterly single neurons activity has been recorded in lateral intraparietal cortex of monkeys performing an uncertain option task, where the subject is allowed to opt for a small but sure reward instead of making a risky perceptual decision. We propose a multiple choice model implemented in a discrete attractors network. This model is able to reproduce both behavioral and neurophysiological experimental data and therefore provides support to the numerous perspectives that interpret the uncertain option task as a sensory-motor association. The model explains the behavioral and neural data recorded in monkeys as the result of the multistable attractor landscape and produces several testable predictions. One of these predictions may help distinguish our model from a recently proposed continuous attractor model.

  12. Multiple Choice Neurodynamical Model of the Uncertain Option Task

    PubMed Central

    Insabato, Andrea; Pannunzi, Mario; Deco, Gustavo

    2017-01-01

    The uncertain option task has been recently adopted to investigate the neural systems underlying the decision confidence. Latterly single neurons activity has been recorded in lateral intraparietal cortex of monkeys performing an uncertain option task, where the subject is allowed to opt for a small but sure reward instead of making a risky perceptual decision. We propose a multiple choice model implemented in a discrete attractors network. This model is able to reproduce both behavioral and neurophysiological experimental data and therefore provides support to the numerous perspectives that interpret the uncertain option task as a sensory-motor association. The model explains the behavioral and neural data recorded in monkeys as the result of the multistable attractor landscape and produces several testable predictions. One of these predictions may help distinguish our model from a recently proposed continuous attractor model. PMID:28076355

  13. Gearbox design for uncertain load requirements using active robust optimization

    NASA Astrophysics Data System (ADS)

    Salomon, Shaul; Avigad, Gideon; Purshouse, Robin C.; Fleming, Peter J.

    2016-04-01

    Design and optimization of gear transmissions have been intensively studied, but surprisingly the robustness of the resulting optimal design to uncertain loads has never been considered. Active Robust (AR) optimization is a methodology to design products that attain robustness to uncertain or changing environmental conditions through adaptation. In this study the AR methodology is utilized to optimize the number of transmissions, as well as their gearing ratios, for an uncertain load demand. The problem is formulated as a bi-objective optimization problem where the objectives are to satisfy the load demand in the most energy efficient manner and to minimize production cost. The results show that this approach can find a set of robust designs, revealing a trade-off between energy efficiency and production cost. This can serve as a useful decision-making tool for the gearbox design process, as well as for other applications.

  14. An Artificial Bee Colony Algorithm for Uncertain Portfolio Selection

    PubMed Central

    Chen, Wei

    2014-01-01

    Portfolio selection is an important issue for researchers and practitioners. In this paper, under the assumption that security returns are given by experts' evaluations rather than historical data, we discuss the portfolio adjusting problem which takes transaction costs and diversification degree of portfolio into consideration. Uncertain variables are employed to describe the security returns. In the proposed mean-variance-entropy model, the uncertain mean value of the return is used to measure investment return, the uncertain variance of the return is used to measure investment risk, and the entropy is used to measure diversification degree of portfolio. In order to solve the proposed model, a modified artificial bee colony (ABC) algorithm is designed. Finally, a numerical example is given to illustrate the modelling idea and the effectiveness of the proposed algorithm. PMID:25089292

  15. Design of piezoelectric transformer for DC/DC converter with stochastic optimization method

    NASA Astrophysics Data System (ADS)

    Vasic, Dejan; Vido, Lionel

    2016-04-01

    Piezoelectric transformers were adopted in recent year due to their many inherent advantages such as safety, no EMI problem, low housing profile, and high power density, etc. The characteristics of the piezoelectric transformers are well known when the load impedance is a pure resistor. However, when piezoelectric transformers are used in AC/DC or DC/DC converters, there are non-linear electronic circuits connected before and after the transformer. Consequently, the output load is variable and due to the output capacitance of the transformer the optimal working point change. This paper starts from modeling a piezoelectric transformer connected to a full wave rectifier in order to discuss the design constraints and configuration of the transformer. The optimization method adopted here use the MOPSO algorithm (Multiple Objective Particle Swarm Optimization). We start with the formulation of the objective function and constraints; then the results give different sizes of the transformer and the characteristics. In other word, this method is looking for a best size of the transformer for optimal efficiency condition that is suitable for variable load. Furthermore, the size and the efficiency are found to be a trade-off. This paper proposes the completed design procedure to find the minimum size of PT in need. The completed design procedure is discussed by a given specification. The PT derived from the proposed design procedure can guarantee both good efficiency and enough range for load variation.

  16. Stochastic quasi-synchronization for uncertain chaotic delayed neural networks

    NASA Astrophysics Data System (ADS)

    Zhang, Shuo; Yu, Yongguang; Wen, Guoguang; Rahmani, Ahmed

    2014-02-01

    The stochastic quasi-synchronization issue for uncertain chaotic delayed neural networks (DNNs) is investigated. Stochastic perturbation and three uncertain elements, including the discontinuous activation functions, mismatched connection weight parameters and unknown connection weight parameters, are considered in the chaotic DNNs. According to the Ito formula and the inequality techniques, the parameters update laws and the control laws are given to realize the synchronization. And a stochastic quasi-synchronization criterion is established. Furthermore, sufficient conditions are proposed for the control of the synchronization error bound by choosing appropriate control laws. Some numerical simulations are presented to demonstrate the effectiveness of the theoretical results.

  17. Whole-Genome Sequence of the Cheese Isolate Lactobacillus rennini ACA-DC 565

    PubMed Central

    Kazou, Maria; Alexandraki, Voula; Pot, Bruno; Tsakalidou, Effie

    2017-01-01

    ABSTRACT In this study, we present the first complete genome sequence of Lactobacillus rennini ACA-DC 565, a strain isolated from a traditional Greek overripened Kopanisti cheese called Mana. Although the species has been associated with cheese spoilage, the strain ACA-DC 565 may contribute to the intense organoleptic characteristics of Mana cheese. PMID:28153908

  18. Greening America's Capitals - Washington, DC

    EPA Pesticide Factsheets

    This Greening America's Capitals report describes design options for the Anacostia Metro station in Washington, DC, that could help people feel safer and more comfortable walking to and from the station.

  19. Wireless Content Repurposing Architecture for DC Command and Control

    DTIC Science & Technology

    2003-09-01

    COMMAND AND CONTROL by Robert J. Suh September 2003 Thesis Advisor: Gurminder Singh Second Reader: Perry McDowell...data sources , gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this...3. REPORT TYPE AND DATES COVERED Master’s Thesis 4. TITLE AND SUBTITLE: Wireless Content Repurposing Architecture for DC Command and Control

  20. A Low-Cost Soft-Switched DC/DC Converter for Solid-Oxide Fuel Cells

    SciTech Connect

    Jason Lai

    2009-03-03

    A highly efficient DC to DC converter has been developed for low-voltage high-current solid oxide fuel cells. The newly developed 'V6' converter resembles what has been done in internal combustion engine that split into multiple cylinders to increase the output capacity without having to increase individual cell size and to smooth out the torque with interleaving operation. The development was started with topology overview to ensure that all the DC to DC converter circuits were included in the study. Efficiency models for different circuit topologies were established, and computer simulations were performed to determine the best candidate converter circuit. Through design optimization including topology selection, device selection, magnetic component design, thermal design, and digital controller design, a bench prototype rated 5-kW, with 20 to 50V input and 200/400V output was fabricated and tested. Efficiency goal of 97% was proven achievable through hardware experiment. This DC to DC converter was then modified in the later stage to converter 35 to 63 V input and 13.8 V output for automotive charging applications. The complete prototype was tested at Delphi with their solid oxide fuel cell test stand to verify the performance of the modified DC to DC converter. The output was tested up to 3-kW level, and the efficiency exceeded 97.5%. Multiple-phase interleaving operation design was proved to be reliable and ripple free at the output, which is desirable for the battery charging. Overall this is a very successful collaboration project between the SECA Core Technology Team and Industrial Team.

  1. Processing uncertain RFID data in traceability supply chains.

    PubMed

    Xie, Dong; Xiao, Jie; Guo, Guangjun; Jiang, Tong

    2014-01-01

    Radio Frequency Identification (RFID) is widely used to track and trace objects in traceability supply chains. However, massive uncertain data produced by RFID readers are not effective and efficient to be used in RFID application systems. Following the analysis of key features of RFID objects, this paper proposes a new framework for effectively and efficiently processing uncertain RFID data, and supporting a variety of queries for tracking and tracing RFID objects. We adjust different smoothing windows according to different rates of uncertain data, employ different strategies to process uncertain readings, and distinguish ghost, missing, and incomplete data according to their apparent positions. We propose a comprehensive data model which is suitable for different application scenarios. In addition, a path coding scheme is proposed to significantly compress massive data by aggregating the path sequence, the position, and the time intervals. The scheme is suitable for cyclic or long paths. Moreover, we further propose a processing algorithm for group and independent objects. Experimental evaluations show that our approach is effective and efficient in terms of the compression and traceability queries.

  2. Gondwanamyia, a new empidoid (Diptera) genus of uncertain placement

    PubMed Central

    Sinclair, Bradley J.; Cumming, Jeffrey M.; Brooks, Scott E.; Plant, Adrian R.; Saigusa, Toyohei

    2016-01-01

    Abstract A new minute-size empidoid fly genus, Gondwanamyia gen. n. and two new species (Gondwanamyia chilensis Cumming & Saigusa, sp. n., Gondwanamyia zealandica Sinclair & Brooks, sp. n.) are described, illustrated, and their distributions mapped. The family and subfamily assignments remain uncertain, but features of the female terminalia potentially suggest Trichopezinae (Brachystomatidae). PMID:27833421

  3. Processing Uncertain RFID Data in Traceability Supply Chains

    PubMed Central

    Xie, Dong; Xiao, Jie

    2014-01-01

    Radio Frequency Identification (RFID) is widely used to track and trace objects in traceability supply chains. However, massive uncertain data produced by RFID readers are not effective and efficient to be used in RFID application systems. Following the analysis of key features of RFID objects, this paper proposes a new framework for effectively and efficiently processing uncertain RFID data, and supporting a variety of queries for tracking and tracing RFID objects. We adjust different smoothing windows according to different rates of uncertain data, employ different strategies to process uncertain readings, and distinguish ghost, missing, and incomplete data according to their apparent positions. We propose a comprehensive data model which is suitable for different application scenarios. In addition, a path coding scheme is proposed to significantly compress massive data by aggregating the path sequence, the position, and the time intervals. The scheme is suitable for cyclic or long paths. Moreover, we further propose a processing algorithm for group and independent objects. Experimental evaluations show that our approach is effective and efficient in terms of the compression and traceability queries. PMID:24737978

  4. An uncertain multidisciplinary design optimization method using interval convex models

    NASA Astrophysics Data System (ADS)

    Li, Fangyi; Luo, Zhen; Sun, Guangyong; Zhang, Nong

    2013-06-01

    This article proposes an uncertain multi-objective multidisciplinary design optimization methodology, which employs the interval model to represent the uncertainties of uncertain-but-bounded parameters. The interval number programming method is applied to transform each uncertain objective function into two deterministic objective functions, and a satisfaction degree of intervals is used to convert both the uncertain inequality and equality constraints to deterministic inequality constraints. In doing so, an unconstrained deterministic optimization problem will be constructed in association with the penalty function method. The design will be finally formulated as a nested three-loop optimization, a class of highly challenging problems in the area of engineering design optimization. An advanced hierarchical optimization scheme is developed to solve the proposed optimization problem based on the multidisciplinary feasible strategy, which is a well-studied method able to reduce the dimensions of multidisciplinary design optimization problems by using the design variables as independent optimization variables. In the hierarchical optimization system, the non-dominated sorting genetic algorithm II, sequential quadratic programming method and Gauss-Seidel iterative approach are applied to the outer, middle and inner loops of the optimization problem, respectively. Typical numerical examples are used to demonstrate the effectiveness of the proposed methodology.

  5. 76 FR 68745 - DC Energy, LLC; DC Energy Mid-Atlantic, LLC

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-07

    ... No: 2011-28690] DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. EL12-8-000] DC Energy, LLC; DC Energy Mid-Atlantic, LLC v. PJM Interconnection, L.L.C.; Notice of Complaint Take notice... Commission (Commission), 18 CFR 385.206 (2011), DC Energy, LLC (DC Energy) and DC Energy Mid-Atlantic...

  6. Commercial Of-The Shelf DC/DC Converter

    NASA Astrophysics Data System (ADS)

    Denzinger, W.; Baumel, S.

    2011-10-01

    A commercial of-the-shelf (COTS) DC/DC converter for the supply of digital electronics on board of spacecraft has been developed with special emphasis on: *Low cost Readily available *Easy manufacturing *No use of ITAR listed EEE parts like rad-hard mosfets *Minimum number of rad-hard digital and analog IC's *Design tolerance against SEE by appropriate filtering The study was supported by the European Space Agency (ESA) under the contract number 21729/08/NL7LvH.

  7. Light-weight DC to very high voltage DC converter

    DOEpatents

    Druce, R.L.; Kirbie, H.C.; Newton, M.A.

    1998-06-30

    A DC-DC converter capable of generating outputs of 100 KV without a transformer comprises a silicon opening switch (SOS) diode connected to allow a charging current from a capacitor to flow into an inductor. When a specified amount of charge has flowed through the SOS diode, it opens up abruptly; and the consequential collapsing field of the inductor causes a voltage and current reversal that is steered into a load capacitor by an output diode. A switch across the series combination of the capacitor, inductor, and SOS diode closes to periodically reset the SOS diode by inducing a forward-biased current. 1 fig.

  8. Light-weight DC to very high voltage DC converter

    DOEpatents

    Druce, Robert L.; Kirbie, Hugh C.; Newton, Mark A.

    1998-01-01

    A DC-DC converter capable of generating outputs of 100 KV without a transformer comprises a silicon opening switch (SOS) diode connected to allow a charging current from a capacitor to flow into an inductor. When a specified amount of charge has flowed through the SOS diode, it opens up abruptly; and the consequential collapsing field of the inductor causes a voltage and current reversal that is steered into a load capacitor by an output diode. A switch across the series combination of the capacitor, inductor, and SOS diode closes to periodically reset the SOS diode by inducing a forward-biased current.

  9. Switching coordination of distributed dc-dc converters for highly efficient photovoltaic power plants

    SciTech Connect

    Agamy, Mohammed; Elasser, Ahmed; Sabate, Juan Antonio; Galbraith, Anthony William; Harfman Todorovic, Maja

    2014-09-09

    A distributed photovoltaic (PV) power plant includes a plurality of distributed dc-dc converters. The dc-dc converters are configured to switch in coordination with one another such that at least one dc-dc converter transfers power to a common dc-bus based upon the total system power available from one or more corresponding strings of PV modules. Due to the coordinated switching of the dc-dc converters, each dc-dc converter transferring power to the common dc-bus continues to operate within its optimal efficiency range as well as to optimize the maximum power point tracking in order to increase the energy yield of the PV power plant.

  10. Performance-Driven Robust Identification and Control of Uncertain Dynamical Systems

    SciTech Connect

    Basar, Tamer

    2001-10-29

    The grant DEFG02-97ER13939 from the Department of Energy has supported our research program on robust identification and control of uncertain dynamical systems, initially for the three-year period June 15, 1997-June 14, 2000, which was then extended on a no-cost basis for another year until June 14, 2001. This final report provides an overview of our research conducted during this period, along with a complete list of publications supported by the Grant. Within the scope of this project, we have studied fundamental issues that arise in modeling, identification, filtering, control, stabilization, control-based model reduction, decomposition and aggregation, and optimization of uncertain systems. The mathematical framework we have worked in has allowed the system dynamics to be only partially known (with the uncertainties being of both parametric or structural nature), and further the dynamics to be perturbed by unknown dynamic disturbances. Our research over these four years has generated a substantial body of new knowledge, and has led to new major developments in theory, applications, and computational algorithms. These have all been documented in various journal articles and book chapters, and have been presented at leading conferences, as to be described. A brief description of the results we have obtained within the scope of this project can be found in Section 3. To set the stage for the material of that section, we first provide in the next section (Section 2) a brief description of the issues that arise in the control of uncertain systems, and introduce several criteria under which optimality will lead to robustness and stability. Section 4 contains a list of references cited in these two sections. A list of our publications supported by the DOE Grant (covering the period June 15, 1997-June 14, 2001) comprises Section 5 of the report.

  11. A general unified approach to modelling switching dc-to-dc converters in discontinuous conduction mode

    NASA Technical Reports Server (NTRS)

    Cuk, S.; Middlebrook, R. D.

    1977-01-01

    A method for modelling switching converters in the discontinuous conduction mode is developed, whose starting point is the unified state-space representation, and whose end result is a complete linear circuit model which correctly represents all essential features, namely, the input, output, and transfer properties (static dc as well as dynamic ac small signal). While the method is generally applicable to any switching converter operating in the discontinuous conduction mode, it is extensively illustrated for the three common power stages (buck, boost, and buck-boost). The results for these converters are then easily tabulated owing to the fixed equivalent circuit topology of their canonical circuit model.

  12. Soft switching active snubbers for DC/DC converters

    SciTech Connect

    Elasser, A.; Torrey, D.A.

    1996-09-01

    A soft-switching active snubber is proposed to reduce the turn-off losses of the insulated gate bipolar transistor (IGBT) in a buck converter. The soft-switching snubber provides zero-voltage switching for the IGBT, thereby reducing its high turn-off losses due to the current tailing. The proposed snubber uses an auxiliary switch to discharge the snubber capacitor. This auxiliary switch also operates at zero-voltage and zero-current switching. The size of the auxiliary switch compared to the main switch makes this snubber a good alternative to the conventional snubber or even to passive low-loss snubbers. The use of the soft-switching active snubber permits the IGBT to operate at high frequencies with an improved RBSOA. In the experimental results reported for a 1 kW, 40 kHz prototype, combined switching/snubbing losses are reduced by 36% through the use of the active snubber compared to a conventional RCD snubber. The use of an active snubber capacitor during turn-off. The generic snubber cell for the buck converter is generalized to support the common nonisolated dc/dc converters (buck, boost, buck-boost, Cuk, sepic, zeta) as well as isolated dc/dc converters (forward, flyback, Cuk, and sepic).

  13. DC coupled Doppler radar physiological monitor.

    PubMed

    Zhao, Xi; Song, Chenyan; Lubecke, Victor; Boric-Lubecke, Olga

    2011-01-01

    One of the challenges in Doppler radar systems for physiological monitoring is a large DC offset in baseband outputs. Typically, AC coupling is used to eliminate this DC offset. Since the physiological signals of interest include frequency content near DC, it is not desirable to simply use AC coupling on the radar outputs. While AC coupling effectively removes DC offset, it also introduces a large time delay and distortion. This paper presents the first DC coupled IQ demodulator printed circuit board (PCB) design and measurements. The DC coupling is achieved by using a mixer with high LO to RF port isolation, resulting in a very low radar DC offset on the order of mV. The DC coupled signals from the PCB radar system were successfully detected with significant LNA gain without saturation. Compared to the AC coupled results, the DC coupled results show great advantages of less signal distortion and more accurate rate estimation.

  14. Error estimation and adaptivity for transport problems with uncertain parameters

    NASA Astrophysics Data System (ADS)

    Sahni, Onkar; Li, Jason; Oberai, Assad

    2016-11-01

    Stochastic partial differential equations (PDEs) with uncertain parameters and source terms arise in many transport problems. In this study, we develop and apply an adaptive approach based on the variational multiscale (VMS) formulation for discretizing stochastic PDEs. In this approach we employ finite elements in the physical domain and generalize polynomial chaos based spectral basis in the stochastic domain. We demonstrate our approach on non-trivial transport problems where the uncertain parameters are such that the advective and diffusive regimes are spanned in the stochastic domain. We show that the proposed method is effective as a local error estimator in quantifying the element-wise error and in driving adaptivity in the physical and stochastic domains. We will also indicate how this approach may be extended to the Navier-Stokes equations. NSF Award 1350454 (CAREER).

  15. Matching Visual Saliency to Confidence in Plots of Uncertain Data

    PubMed Central

    Feng, David; Kwock, Lester; Lee, Yueh; Taylor, Russell M.

    2011-01-01

    Conveying data uncertainty in visualizations is crucial for preventing viewers from drawing conclusions based on untrustworthy data points. This paper proposes a methodology for efficiently generating density plots of uncertain multivariate data sets that draws viewers to preattentively identify values of high certainty while not calling attention to uncertain values. We demonstrate how to augment scatter plots and parallel coordinates plots to incorporate statistically modeled uncertainty and show how to integrate them with existing multivariate analysis techniques, including outlier detection and interactive brushing. Computing high quality density plots can be expensive for large data sets, so we also describe a probabilistic plotting technique that summarizes the data without requiring explicit density plot computation. These techniques have been useful for identifying brain tumors in multivariate magnetic resonance spectroscopy data and we describe how to extend them to visualize ensemble data sets. PMID:20975135

  16. Fuzzy control for linear plants with uncertain output backlashes.

    PubMed

    Tao, C W

    2002-01-01

    In this correspondence, a new approach to design a fuzzy controller for systems with uncertain output backlash to have good tracking performance is presented. Without using a compensation mechanism or a backlash inverse, the fuzzy control mechanism is designed to implicitly compensate the delay effect arising from an uncertain output backlash and to make the output backlash system stable without limit cycles. Also, the proposed fuzzy controller is presented to be insensitive to the variations of the backlash and system plant parameters. Moreover, the proposed approach is extended to design a fuzzy controller for a two-input two-output (TITO) linear plant with output backlash. The effectiveness of the designed fuzzy controller is illustrated by the simulation results on linear, low-order, nonlinear plants and the experimental results on an amplifier-motor system with a gear train.

  17. Adapting environmental management to uncertain but inevitable change

    PubMed Central

    Nicol, Sam; Fuller, Richard A.; Iwamura, Takuya; Chadès, Iadine

    2015-01-01

    Implementation of adaptation actions to protect biodiversity is limited by uncertainty about the future. One reason for this is the fear of making the wrong decisions caused by the myriad future scenarios presented to decision-makers. We propose an adaptive management (AM) method for optimally managing a population under uncertain and changing habitat conditions. Our approach incorporates multiple future scenarios and continually learns the best management strategy from observations, even as conditions change. We demonstrate the performance of our AM approach by applying it to the spatial management of migratory shorebird habitats on the East Asian–Australasian flyway, predicted to be severely impacted by future sea-level rise. By accounting for non-stationary dynamics, our solution protects 25 000 more birds per year than the current best stationary approach. Our approach can be applied to many ecological systems that require efficient adaptation strategies for an uncertain future. PMID:25972463

  18. Probabilistic Motion Planning of Balloons in Strong, Uncertain Wind Fields

    NASA Technical Reports Server (NTRS)

    Wolf, Michael T.; Blackmore, Lars; Kuwata, Yoshiaki; Fathpour, Nanaz; Elfes, Alberto; Newman, Claire

    2010-01-01

    This paper introduces a new algorithm for probabilistic motion planning in arbitrary, uncertain vector fields, with emphasis on high-level planning for Montgolfiere balloons in the atmosphere of Titan. The goal of the algorithm is to determine what altitude--and what horizontal actuation, if any is available on the vehicle--to use to reach a goal location in the fastest expected time. The winds can vary greatly at different altitudes and are strong relative to any feasible horizontal actuation, so the incorporation of the winds is critical for guidance plans. This paper focuses on how to integrate the uncertainty of the wind field into the wind model and how to reach a goal location through the uncertain wind field, using a Markov decision process (MDP). The resulting probabilistic solutions enable more robust guidance plans and more thorough analysis of potential paths than existing methods.

  19. Global tracking for a class of uncertain nonlinear systems with unknown sign-switching control direction by output feedback

    NASA Astrophysics Data System (ADS)

    Roux Oliveira, Tiago; Jacoud Peixoto, Alessandro; Hsu, Liu

    2015-09-01

    This paper addresses the design of a sliding mode controller for a class of high-order uncertain nonlinear plants with unmatched state-dependent nonlinearities and unknown sign of the high frequency gain, i.e., the control direction is assumed unknown. Differently from most previous studies, the control direction is allowed to switch its sign. We show that it is possible to obtain global exact tracking using only output-feedback by coupling a relay periodic switching function with a norm state observer. One significant advantage of the new scheme is its robustness and improved transient response under arbitrary changes of the control direction which have been theoretically demonstrated for jump variations and successfully tested by simulations. The proposed controller is also evaluated with a DC motor control experiment.

  20. Design Flexibility for Uncertain Distributed Generation from Photovoltaics

    SciTech Connect

    Palmintier, Bryan; Krishnamurthy, Dheepak; Wu, Hongyu

    2016-12-12

    Uncertainty in the future adoption patterns for distributed energy resources (DERs) introduces a challenge for electric distribution system planning. This paper explores the potential for flexibility in design - also known as real options - to identify design solutions that may never emerge when future DER patterns are treated as deterministic. A test case for storage system design with uncertain distributed generation for solar photovoltaics (DGPV) demonstrates this approach and is used to study sensitivities to a range of techno-economic assumptions.

  1. Distributed control systems with incomplete and uncertain information

    NASA Astrophysics Data System (ADS)

    Tang, Jingpeng

    Scientific and engineering advances in wireless communication, sensors, propulsion, and other areas are rapidly making it possible to develop unmanned air vehicles (UAVs) with sophisticated capabilities. UAVs have come to the forefront as tools for airborne reconnaissance to search for, detect, and destroy enemy targets in relatively complex environments. They potentially reduce risk to human life, are cost effective, and are superior to manned aircraft for certain types of missions. It is desirable for UAVs to have a high level of intelligent autonomy to carry out mission tasks with little external supervision and control. This raises important issues involving tradeoffs between centralized control and the associated potential to optimize mission plans, and decentralized control with great robustness and the potential to adapt to changing conditions. UAV capabilities have been extended several ways through armament (e.g., Hellfire missiles on Predator UAVs), increased endurance and altitude (e.g., Global Hawk), and greater autonomy. Some known barriers to full-scale implementation of UAVs are increased communication and control requirements as well as increased platform and system complexity. One of the key problems is how UAV systems can handle incomplete and uncertain information in dynamic environments. Especially when the system is composed of heterogeneous and distributed UAVs, the overall system complexity is increased under such conditions. Presented through the use of published papers, this dissertation lays the groundwork for the study of methodologies for handling incomplete and uncertain information for distributed control systems. An agent-based simulation framework is built to investigate mathematical approaches (optimization) and emergent intelligence approaches. The first paper provides a mathematical approach for systems of UAVs to handle incomplete and uncertain information. The second paper describes an emergent intelligence approach for UAVs

  2. Linear control design for guaranteed stability of uncertain linear systems

    NASA Technical Reports Server (NTRS)

    Yedavalli, R. K.

    1986-01-01

    In this paper, a linear control design algorithm based on the elemental perturbation bounds developed recently is presented for a simple second order linear uncertain system satisfying matching conditions. The proposed method is compared with Guaranteed Cost Control (GCC), Multistep Guaranteed Cost Control (MGCC) and the Matching Condition (MC) methods and is shown to give guaranteed stability with lesser values for the control gains than some of the existing methods for the example considered.

  3. Robustified time-optimal control of uncertain structural dynamic systems

    NASA Technical Reports Server (NTRS)

    Liu, Qiang; Wie, Bong

    1991-01-01

    A new approach for computing open-loop time-optimal control inputs for uncertain linear dynamical systems is developed. In particular, the single-axis, rest-to-rest maneuvering problem of flexible spacecraft in the presence of uncertainty in model parameters is considered. Robustified time-optimal control inputs are obtained by solving a parameter optimization problem subject to robustness constraints. A simple dynamical system with a rigid-body mode and one flexible mode is used to illustrate the concept.

  4. Probabilistic Verification of Multi-Robot Missions in Uncertain Environments

    DTIC Science & Technology

    2015-11-01

    However, establishing a guarantee for the behavior of an autonomous robot operating in an uncertain environment with obstacles is a challenging problem...This paper addresses the challenges involved in building a software tool for verifying the behavior of a multi-robot waypoint mission that...this approach on a two-robot, bounding overwatch mission. Keywords-component; Probabilistic Verification, Validation, Multi-robot Missions, Behavior

  5. Path planning in uncertain flow fields using ensemble method

    NASA Astrophysics Data System (ADS)

    Wang, Tong; Le Maître, Olivier P.; Hoteit, Ibrahim; Knio, Omar M.

    2016-10-01

    An ensemble-based approach is developed to conduct optimal path planning in unsteady ocean currents under uncertainty. We focus our attention on two-dimensional steady and unsteady uncertain flows, and adopt a sampling methodology that is well suited to operational forecasts, where an ensemble of deterministic predictions is used to model and quantify uncertainty. In an operational setting, much about dynamics, topography, and forcing of the ocean environment is uncertain. To address this uncertainty, the flow field is parametrized using a finite number of independent canonical random variables with known densities, and the ensemble is generated by sampling these variables. For each of the resulting realizations of the uncertain current field, we predict the path that minimizes the travel time by solving a boundary value problem (BVP), based on the Pontryagin maximum principle. A family of backward-in-time trajectories starting at the end position is used to generate suitable initial values for the BVP solver. This allows us to examine and analyze the performance of the sampling strategy and to develop insight into extensions dealing with general circulation ocean models. In particular, the ensemble method enables us to perform a statistical analysis of travel times and consequently develop a path planning approach that accounts for these statistics. The proposed methodology is tested for a number of scenarios. We first validate our algorithms by reproducing simple canonical solutions, and then demonstrate our approach in more complex flow fields, including idealized, steady and unsteady double-gyre flows.

  6. DC-Powered Jumping Ring

    ERIC Educational Resources Information Center

    Jeffery, Rondo N.; Farhang, Amiri

    2016-01-01

    The classroom jumping ring demonstration is nearly always performed using alternating current (AC), in which the ring jumps or flies off the extended iron core when the switch is closed. The ring jumps higher when cooled with liquid nitrogen (LN2). We have performed experiments using DC to power the solenoid and find similarities and significant…

  7. Experiments with a DC Motor

    ERIC Educational Resources Information Center

    Kraftmakher, Yaakov

    2010-01-01

    Experiments with an electric motor provide good opportunity to demonstrate some basic laws of electricity and magnetism. The aim of the experiments with a low-power dc motor is to show how the motor approaches its steady rotation and how its torque, mechanical power and efficiency depend on the rotation velocity. The tight relationship between the…

  8. Compact integrated dc SQUID gradiometer

    SciTech Connect

    de Waal, V.J.; Klapwijk, T.M.

    1982-10-01

    An all-niobium integrated system of first-order gradiometer and dc suprconducting quantum interference device (SQUID) has been developed. It is relatively simple to fabricate, has an overall size of 17 x 12 mm and a sensitivity of 3.5 x 10/sup -12/ T m/sup -1/ Hz/sup -1/2/.

  9. Designing dc Inductors With Airgaps

    NASA Technical Reports Server (NTRS)

    Wagner, A. P.

    1986-01-01

    Optimal parameters obtained designing near saturation point. New iterative procedure aids design of dc inductors with airgaps in cores. For given core area and length, technique gives design having specified inductance and peak flux density in core, using minimum required copper weight. Executed rapidly on programmable, hand-held calculator. Applications include lightweight inductors for aircraft electronics.

  10. 76 FR 53346 - Airworthiness Directives; The Boeing Company Model DC-9-81 (MD-81), DC-9-82 (MD-82), DC-9-83 (MD...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-26

    ... Model DC-9-81 (MD- 81), DC-9-82 (MD-82), DC-9-83 (MD-83), DC-9-87 (MD-87), and MD-88 Airplanes AGENCY... Jersey Avenue, SE., Washington, DC 20590. Hand Delivery: Deliver to Mail address above between 9 a.m. and...) This AD applies to The Boeing Company Model DC-9-81 (MD-81), DC-9-82 (MD-82), DC-9-83 (MD-83),...

  11. 75 FR 68686 - Airworthiness Directives; McDonnell Douglas Corporation Model DC-9-14, DC-9-15, and DC-9-15F...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-09

    ...; AD 2010-23-10] RIN 2120-AA64 Airworthiness Directives; McDonnell Douglas Corporation Model DC- 9-14, DC-9-15, and DC-9-15F Airplanes; and Model DC-9-20, DC-9-30, DC- 9-40, and DC-9-50 Series Airplanes... Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590. FOR FURTHER...

  12. 75 FR 62331 - Airworthiness Directives; McDonnell Douglas Corporation Model DC-9-14, DC-9-15, and DC-9-15F...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-08

    ... Directives; McDonnell Douglas Corporation Model DC- 9-14, DC-9-15, and DC-9-15F Airplanes; and DC-9-20, DC-9-30, DC-9-40, and DC-9-50 Series Airplanes AGENCY: Federal Aviation Administration (FAA), DOT. ACTION... Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590. Hand Delivery: Deliver to...

  13. 76 FR 1993 - Airworthiness Directives; The Boeing Company Model DC-9-81 (MD-81), DC-9-82 (MD-82), DC-9-83 (MD...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-12

    ... Model DC-9-81 (MD- 81), DC-9-82 (MD-82), DC-9-83 (MD-83), DC-9-87 (MD-87), and MD-88 Airplanes AGENCY... Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590. FOR FURTHER INFORMATION.... Applicability (c) This AD applies to The Boeing Company Model DC-9-81 (MD-81), DC-9-82 (MD-82), DC-9-83...

  14. 76 FR 41651 - Airworthiness Directives; The Boeing Company Model DC-9-81 (MD-81), DC-9-82 (MD-82), DC-9-83 (MD...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-15

    ... Model DC-9-81 (MD- 81), DC-9-82 (MD-82), DC-9-83 (MD-83), DC-9-87 (MD-87), and MD-88 Airplanes AGENCY... Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590. FOR FURTHER INFORMATION...) This AD applies to The Boeing Company Model DC-9-81 (MD-81), DC-9-82 (MD-82), DC-9-83 (MD-83),...

  15. 76 FR 39251 - Airworthiness Directives; The Boeing Company Model DC-9-81 (MD-81), DC-9-82 (MD-82), DC-9-83 (MD...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-06

    ... Model DC-9-81 (MD- 81), DC-9-82 (MD-82), DC-9-83 (MD-83), DC-9-87 (MD-87), and MD-88 Airplanes AGENCY... Jersey Avenue, SE., Washington, DC 20590. FOR FURTHER INFORMATION CONTACT: Roger Durbin, Aerospace.... Applicability (c) This AD applies to all The Boeing Company Model DC-9-81 (MD- 81), DC-9-82 (MD-82), DC-9-83...

  16. Electrostatic coalescence system with independent AC and DC hydrophilic electrodes

    DOEpatents

    Hovarongkura, A. David; Henry, Jr., Joseph D.

    1981-01-01

    An improved electrostatic coalescence system is provided in which independent AC and DC hydrophilic electrodes are employed to provide more complete dehydration of an oil emulsion. The AC field is produced between an AC electrode array and the water-oil interface wherein the AC electrode array is positioned parallel to the interface which acts as a grounded electrode. The emulsion is introduced into the AC field in an evenly distributed manner at the interface. The AC field promotes drop-drop and drop-interface coalescence of the water phase in the entering emulsion. The continuous oil phase passes upward through the perforated AC electrode array and enters a strong DC field produced between closely spaced DC electrodes in which small dispersed droplets of water entrained in the continuous phase are removed primarily by collection at hydrophilic DC electrodes. Large droplets of water collected by the electrodes migrate downward through the AC electrode array to the interface. All phase separation mechanisms are utilized to accomplish more complete phase separation.

  17. Identification of cDC1- and cDC2-committed DC progenitors reveals early lineage priming at the common DC progenitor stage in the bone marrow.

    PubMed

    Schlitzer, Andreas; Sivakamasundari, V; Chen, Jinmiao; Sumatoh, Hermi Rizal Bin; Schreuder, Jaring; Lum, Josephine; Malleret, Benoit; Zhang, Sanqian; Larbi, Anis; Zolezzi, Francesca; Renia, Laurent; Poidinger, Michael; Naik, Shalin; Newell, Evan W; Robson, Paul; Ginhoux, Florent

    2015-07-01

    Mouse conventional dendritic cells (cDCs) can be classified into two functionally distinct lineages: the CD8α(+) (CD103(+)) cDC1 lineage, and the CD11b(+) cDC2 lineage. cDCs arise from a cascade of bone marrow (BM) DC-committed progenitor cells that include the common DC progenitors (CDPs) and pre-DCs, which exit the BM and seed peripheral tissues before differentiating locally into mature cDCs. Where and when commitment to the cDC1 or cDC2 lineage occurs remains poorly understood. Here we found that transcriptional signatures of the cDC1 and cDC2 lineages became evident at the single-cell level from the CDP stage. We also identified Siglec-H and Ly6C as lineage markers that distinguished pre-DC subpopulations committed to the cDC1 lineage (Siglec-H(-)Ly6C(-) pre-DCs) or cDC2 lineage (Siglec-H(-)Ly6C(+) pre-DCs). Our results indicate that commitment to the cDC1 or cDC2 lineage occurs in the BM and not in the periphery.

  18. DC to DC power converters and methods of controlling the same

    DOEpatents

    Steigerwald, Robert Louis; Elasser, Ahmed; Sabate, Juan Antonio; Todorovic, Maja Harfman; Agamy, Mohammed

    2012-12-11

    A power generation system configured to provide direct current (DC) power to a DC link is described. The system includes a first power generation unit configured to output DC power. The system also includes a first DC to DC converter comprising an input section and an output section. The output section of the first DC to DC converter is coupled in series with the first power generation unit. The first DC to DC converter is configured to process a first portion of the DC power output by the first power generation unit and to provide an unprocessed second portion of the DC power output of the first power generation unit to the output section.

  19. DC Water: 2009 Presidential Inauguration Supporting Documentation

    EPA Pesticide Factsheets

    DC Water located in Washington, DC incurred costs for activities related to the Presidential Inauguration in January 2009. Support included the purchase and installation of special manhole covers with security features.

  20. Combination of DC Vaccine and Conventional Chemotherapeutics.

    PubMed

    Dong, Wei; Wei, Ran; Shen, Hongchang; Ni, Yang; Meng, Long; Du, Jiajun

    2016-01-01

    Recently mutual interactions of chemotherapy and immunotherapy have been widely accepted, and several synergistic mechanisms have been elucidated as well. Although much attention has focused on the combination of DC vaccine and chemotherapy, there are still many problems remaining to be resolved, including the optimal treatment schedule of the novel strategy. In this article, we methodically examined literature about the combination strategy of DC vaccine and conventional chemotherapy. Based on the published preclinical and clinical trials, treatment schedules of the combinational strategy can be classified as three modalities: chemotherapy with subsequent DC vaccine (post-DC therapy); DC vaccine followed by chemotherapy (pre-DC therapy); concurrent DC vaccine with chemotherapy (con-DC therapy).The safety and efficacy of this combinatorial immunotherapy strategy and its potential mechanisms are discussed. Although we could not draw conclusions on optimal treatment schedule, we summarize some tips which may be beneficial to trial design in the future.

  1. OPUS: Optimal Projection for Uncertain Systems. Volume 1

    DTIC Science & Technology

    1991-09-01

    Haddad, Florida Institute of TechnologyI For Air Force Office of Scientific Research (AFOSR) Boiling Air Force Base Washington, DC 20332 jrXC~SI~f...Controller Structure Design, " Proceedings of the 80th Structures, Structural Dynam- I ics, a Materials Conference, paper 89-1170, Mobile , AL, April 1989

  2. Synchronization of hyperchaotic rossler system with uncertain parameters via nonlinear control

    NASA Astrophysics Data System (ADS)

    Dong, En-Zeng; Chen, Zeng-Qiang; Yuan, Zhu-Zhi

    2006-09-01

    Based on the Lyapunov stability theory, a new method for synchronization of hyperchaotic Rossler system with uncertain parameters is proposed. By this method, choosing appropriate control law and adaptive update law of uncertain parameters, all the errors of system variable synchronization and of uncertain parameter track are asymptotically stable. The theoretical analysis and the numerical simulations prove the effectiveness of the proposed method.

  3. Ecological benefits of dc power transmission

    SciTech Connect

    Kutuzova, N. B.

    2011-05-15

    The environmental effects of dc overhead transmission lines are examined. The major effects of ac and dc transmission lines are compared. Dc lines have advantages compared to ac lines in terms of electrical safety for people under the lines, biological effects, corona losses, and clearance width.

  4. 49 CFR 372.219 - Washington, DC

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 5 2013-10-01 2013-10-01 false Washington, DC 372.219 Section 372.219... ZONES, AND TERMINAL AREAS Commercial Zones § 372.219 Washington, DC The zone adjacent to, and... points within a line drawn 15 miles beyond the municipal limits of Washington, DC (c) All points...

  5. 49 CFR 372.219 - Washington, DC

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 5 2010-10-01 2010-10-01 false Washington, DC 372.219 Section 372.219... ZONES, AND TERMINAL AREAS Commercial Zones § 372.219 Washington, DC The zone adjacent to, and... points within a line drawn 15 miles beyond the municipal limits of Washington, DC (c) All points...

  6. 49 CFR 372.219 - Washington, DC

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 5 2014-10-01 2014-10-01 false Washington, DC 372.219 Section 372.219... ZONES, AND TERMINAL AREAS Commercial Zones § 372.219 Washington, DC The zone adjacent to, and... points within a line drawn 15 miles beyond the municipal limits of Washington, DC (c) All points...

  7. 49 CFR 372.219 - Washington, DC

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 5 2012-10-01 2012-10-01 false Washington, DC 372.219 Section 372.219... ZONES, AND TERMINAL AREAS Commercial Zones § 372.219 Washington, DC The zone adjacent to, and... points within a line drawn 15 miles beyond the municipal limits of Washington, DC (c) All points...

  8. 49 CFR 372.219 - Washington, DC

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 5 2011-10-01 2011-10-01 false Washington, DC 372.219 Section 372.219... ZONES, AND TERMINAL AREAS Commercial Zones § 372.219 Washington, DC The zone adjacent to, and... points within a line drawn 15 miles beyond the municipal limits of Washington, DC (c) All points...

  9. Full wave dc-to-dc converter using energy storage transformers

    NASA Technical Reports Server (NTRS)

    Moore, E. T.; Wilson, T. G.

    1969-01-01

    Full wave dc-to-dc converter, for an ion thrustor, uses energy storage transformers to provide a method of dc-to-dc conversion and regulation. The converter has a high degree of physical simplicity, is lightweight and has high efficiency.

  10. 14 CFR 93.339 - Requirements for operating in the DC SFRA, including the DC FRZ.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 2 2014-01-01 2014-01-01 false Requirements for operating in the DC SFRA, including the DC FRZ. 93.339 Section 93.339 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION... Washington, DC Metropolitan Area Special Flight Rules Area § 93.339 Requirements for operating in the DC...

  11. 14 CFR 93.339 - Requirements for operating in the DC SFRA, including the DC FRZ.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false Requirements for operating in the DC SFRA, including the DC FRZ. 93.339 Section 93.339 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION... Washington, DC Metropolitan Area Special Flight Rules Area § 93.339 Requirements for operating in the DC...

  12. 14 CFR 93.339 - Requirements for operating in the DC SFRA, including the DC FRZ.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 2 2013-01-01 2013-01-01 false Requirements for operating in the DC SFRA, including the DC FRZ. 93.339 Section 93.339 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION... Washington, DC Metropolitan Area Special Flight Rules Area § 93.339 Requirements for operating in the DC...

  13. 14 CFR 93.339 - Requirements for operating in the DC SFRA, including the DC FRZ.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 2 2012-01-01 2012-01-01 false Requirements for operating in the DC SFRA, including the DC FRZ. 93.339 Section 93.339 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION... Washington, DC Metropolitan Area Special Flight Rules Area § 93.339 Requirements for operating in the DC...

  14. 14 CFR 93.339 - Requirements for operating in the DC SFRA, including the DC FRZ.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 2 2011-01-01 2011-01-01 false Requirements for operating in the DC SFRA, including the DC FRZ. 93.339 Section 93.339 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION... Washington, DC Metropolitan Area Special Flight Rules Area § 93.339 Requirements for operating in the DC...

  15. Robust projective outer synchronization of coupled uncertain fractional-order complex networks

    NASA Astrophysics Data System (ADS)

    Wang, Junwei; Zhang, Yun

    2013-06-01

    In this work, we propose a novel projective outer synchronization (POS) between unidirectionally coupled uncertain fractional-order complex networks through scalar transmitted signals. Based on the state observer theory, a control law is designed and some criteria are given in terms of linear matrix inequalities which guarantee global robust POS between such networks. Interestingly, in the POS regime, we show that different choices of scaling factor give rise to different outer synchrony, with various special cases including complete outer synchrony, anti-outer synchrony and even a state of amplitude death. Furthermore, it is demonstrated that although stability of POS is irrelevant to the inner-coupling strength, it will affect the convergence speed of POS. In particular, stronger inner synchronization can induce faster POS. The effectiveness of our method is revealed by numerical simulations on fractional-order complex networks with small-world communication topology.

  16. 75 FR 36579 - Airworthiness Directives; McDonnell Douglas Corporation Model DC-10-30, DC-10-30F, DC-10-30F (KC...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-28

    ... Corporation Model DC- 10-30, DC-10-30F, DC-10-30F (KC-10A and KDC-10), DC-10-40, DC-10-40F, and MD-10-30F...). SUMMARY: We propose to adopt a new airworthiness directive (AD) for certain Model DC-10-30, DC-10-30F, DC-10-30F (KC-10A and KDC-10), DC- 10-40, DC10-40F, and MD-10-30F airplanes. This proposed AD...

  17. 75 FR 61352 - Airworthiness Directives; McDonnell Douglas Corporation Model DC-10-30, DC-10-30F, DC-10-30F (KC...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-05

    ... Corporation Model DC- 10-30, DC-10-30F, DC-10-30F (KC-10A and KDC-10), DC-10-40, DC-10-40F, and MD-10-30F... new airworthiness directive (AD) for certain Model DC-10-30, DC-10-30F, DC-10-30F (KC-10A and KDC-10), DC-10-40, DC- 10-40F, and MD-10-30F airplanes. This AD requires doing a one-time inspection of...

  18. DC-Powered Jumping Ring

    NASA Astrophysics Data System (ADS)

    Jeffery, Rondo N.; Amiri, Farhang

    2016-02-01

    The classroom jumping ring demonstration is nearly always performed using alternating current (AC), in which the ring jumps or flies off the extended iron core when the switch is closed. The ring jumps higher when cooled with liquid nitrogen (LN2). We have performed experiments using DC to power the solenoid and find similarities and significant differences from the AC case. In particular, the ring does not fly off the core but rises a short distance and then falls back. If the ring jumps high enough, the rising and the falling motion of the ring does not follow simple vertical motion of a projectile. This indicates that there are additional forces on the ring in each part of its motion. Four possible stages of the motion of the ring with DC are identified, which result from the ring current changing directions during the jump in response to a changing magnetic flux through the moving ring.

  19. Washington: A DC Circuit Tour

    NASA Astrophysics Data System (ADS)

    Halpern, Paul

    2010-12-01

    I explore the history of physics in Washington, D.C., and its environs through a tour of notable sites and personalities. Highlights include visits to the Smithsonian and Carnegie Institutions, stops at the Einstein Memorial, George Washington University, the University of Maryland, and the American Center for Physics, and biographical sketches of physicists Joseph Henry, George Gamow, Edward Teller, and others who worked in the District of Columbia.

  20. Global adaptive control for uncertain nonaffine nonlinear hysteretic systems.

    PubMed

    Liu, Yong-Hua; Huang, Liangpei; Xiao, Dongming; Guo, Yong

    2015-09-01

    In this paper, the global output tracking is investigated for a class of uncertain nonlinear hysteretic systems with nonaffine structures. By combining the solution properties of the hysteresis model with the novel backstepping approach, a robust adaptive control algorithm is developed without constructing a hysteresis inverse. The proposed control scheme is further modified to tackle the bounded disturbances by adaptively estimating their bounds. It is rigorously proven that the designed adaptive controllers can guarantee global stability of the closed-loop system. Two numerical examples are provided to show the effectiveness of the proposed control schemes.

  1. Assessing risk based on uncertain avalanche activity patterns

    NASA Astrophysics Data System (ADS)

    Zeidler, Antonia; Fromm, Reinhard

    2015-04-01

    Avalanches may affect critical infrastructure and may cause great economic losses. The planning horizon of infrastructures, e.g. hydropower generation facilities, reaches well into the future. Based on the results of previous studies on the effect of changing meteorological parameters (precipitation, temperature) and the effect on avalanche activity we assume that there will be a change of the risk pattern in future. The decision makers need to understand what the future might bring to best formulate their mitigation strategies. Therefore, we explore a commercial risk software to calculate risk for the coming years that might help in decision processes. The software @risk, is known to many larger companies, and therefore we explore its capabilities to include avalanche risk simulations in order to guarantee a comparability of different risks. In a first step, we develop a model for a hydropower generation facility that reflects the problem of changing avalanche activity patterns in future by selecting relevant input parameters and assigning likely probability distributions. The uncertain input variables include the probability of avalanches affecting an object, the vulnerability of an object, the expected costs for repairing the object and the expected cost due to interruption. The crux is to find the distribution that best represents the input variables under changing meteorological conditions. Our focus is on including the uncertain probability of avalanches based on the analysis of past avalanche data and expert knowledge. In order to explore different likely outcomes we base the analysis on three different climate scenarios (likely, worst case, baseline). For some variables, it is possible to fit a distribution to historical data, whereas in cases where the past dataset is insufficient or not available the software allows to select from over 30 different distribution types. The Monte Carlo simulation uses the probability distribution of uncertain variables

  2. Multiobjective insensitive design of airplane control systems with uncertain parameters

    NASA Technical Reports Server (NTRS)

    Schy, A. A.; Giesy, D. P.

    1981-01-01

    A multiobjective computer-aided design algorithm has been developed which minimizes the sensitivity of the design objectives to uncertainties in system parameters. The more important uncertain parameters are described by a gaussian random vector with known covariance matrix, and a vector sensitivity objective function is defined as the probabilities that the design objectives will violate specified requirements constraints. Control system parameters are found which minimize the sensitivity vector in a Pareto-optimal sense, using constrained minimization algorithms. Example results are shown for lateral stability augmentation system (SAS) design for three Shuttle flight conditions.

  3. Synchronization of an uncertain chaotic system via recurrent neural networks

    NASA Astrophysics Data System (ADS)

    Tan, Wen; Wang, Yao-Nan

    2005-01-01

    Incorporating distributed recurrent networks with high-order connections between neurons, the identification and synchronization problem of an unknown chaotic system in the presence of unmodelled dynamics is investigated. Based on the Lyapunov stability theory, the weights learning algorithm for the recurrent high-order neural network model is presented. Also, analytical results concerning the stability properties of the scheme are obtained. Then adaptive control law for eliminating synchronization error of uncertain chaotic plant is developed via Lyapunov methodology. The proposed scheme is applied to model and synchronize an unknown Rossler system.

  4. When, not if: The inescapability of an uncertain future

    NASA Astrophysics Data System (ADS)

    Lewandowsky, S.; Ballard, T.

    2014-12-01

    Uncertainty is an inherent feature of most scientific endeavours, and many political decisions must be made in the presence of scientific uncertainty. In the case of climate change, there is evidence that greater scientific uncertainty increases the risk associated with the impact of climate change. Scientific uncertainty thus provides an impetus for cutting emissions rather than delaying action. In contrast to those normative considerations, uncertainty is frequently cited in political and public discourse as a reason to delay mitigation. We examine ways in which this gap between public and scientific understanding of uncertainty can be bridged. In particular, we sought ways to communicate uncertainty in a way that better calibrates people's risk perceptions with the projected impact of climate change. We report two behavioural experiments in which uncertainty about the future was expressed either as outcome uncertainty or temporal uncertainty. The conventional presentation of uncertainty involves uncertainty about an outcome at a given time—for example, the range of possible sea level rise (say 50cm +/- 20cm) by a certain date. An alternative presentation of the same situation presents a certain outcome ("sea levels will rise by 50cm") but places the uncertainty into the time of arrival ("this may occur as early as 2040 or as late as 2080"). We presented participants with a series of statements and graphs indicating projected increases in temperature, sea levels, ocean acidification, and a decrease in artic sea ice. In the uncertain magnitude condition, the statements and graphs reported the upper and lower confidence bounds of the projected magnitude and the mean projected time of arrival. In the uncertain time of arrival condition, they reported the upper and lower confidence bounds of the projected time of arrival and the mean projected magnitude. The results show that when uncertainty was presented as uncertain time of arrival rather than an uncertain

  5. 76 FR 13543 - Airworthiness Directives; The Boeing Company Model DC-9-81 (MD-81), DC-9-82 (MD-82), DC-9-83 (MD...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-14

    ... Model DC-9-81 (MD- 81), DC-9-82 (MD-82), DC-9-83 (MD-83), DC-9-87 (MD-87), and MD-88 Airplanes AGENCY... Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590. Hand Delivery: Deliver to Mail... stabilizer is similar in design and loading to that of the Model DC-9-81 (MD-81), DC- 9-82 (MD-82),...

  6. Assimilating uncertain, dynamic and intermittent streamflow observations in hydrological models

    NASA Astrophysics Data System (ADS)

    Mazzoleni, Maurizio; Alfonso, Leonardo; Chacon-Hurtado, Juan; Solomatine, Dimitri

    2015-09-01

    Catastrophic floods cause significant socio-economical losses. Non-structural measures, such as real-time flood forecasting, can potentially reduce flood risk. To this end, data assimilation methods have been used to improve flood forecasts by integrating static ground observations, and in some cases also remote sensing observations, within water models. Current hydrologic and hydraulic research works consider assimilation of observations coming from traditional, static sensors. At the same time, low-cost, mobile sensors and mobile communication devices are becoming also increasingly available. The main goal and innovation of this study is to demonstrate the usefulness of assimilating uncertain streamflow observations that are dynamic in space and intermittent in time in the context of two different semi-distributed hydrological model structures. The developed method is applied to the Brue basin, where the dynamic observations are imitated by the synthetic observations of discharge. The results of this study show how model structures and sensors locations affect in different ways the assimilation of streamflow observations. In addition, it proves how assimilation of such uncertain observations from dynamic sensors can provide model improvements similar to those of streamflow observations coming from a non-optimal network of static physical sensors. This can be a potential application of recent efforts to build citizen observatories of water, which can make the citizens an active part in information capturing, evaluation and communication, helping simultaneously to improvement of model-based flood forecasting.

  7. Strict Constraint Feasibility in Analysis and Design of Uncertain Systems

    NASA Technical Reports Server (NTRS)

    Crespo, Luis G.; Giesy, Daniel P.; Kenny, Sean P.

    2006-01-01

    This paper proposes a methodology for the analysis and design optimization of models subject to parametric uncertainty, where hard inequality constraints are present. Hard constraints are those that must be satisfied for all parameter realizations prescribed by the uncertainty model. Emphasis is given to uncertainty models prescribed by norm-bounded perturbations from a nominal parameter value, i.e., hyper-spheres, and by sets of independently bounded uncertain variables, i.e., hyper-rectangles. These models make it possible to consider sets of parameters having comparable as well as dissimilar levels of uncertainty. Two alternative formulations for hyper-rectangular sets are proposed, one based on a transformation of variables and another based on an infinity norm approach. The suite of tools developed enable us to determine if the satisfaction of hard constraints is feasible by identifying critical combinations of uncertain parameters. Since this practice is performed without sampling or partitioning the parameter space, the resulting assessments of robustness are analytically verifiable. Strategies that enable the comparison of the robustness of competing design alternatives, the approximation of the robust design space, and the systematic search for designs with improved robustness characteristics are also proposed. Since the problem formulation is generic and the solution methods only require standard optimization algorithms for their implementation, the tools developed are applicable to a broad range of problems in several disciplines.

  8. Global sensitivity analysis in stochastic simulators of uncertain reaction networks.

    PubMed

    Navarro Jimenez, M; Le Maître, O P; Knio, O M

    2016-12-28

    Stochastic models of chemical systems are often subjected to uncertainties in kinetic parameters in addition to the inherent random nature of their dynamics. Uncertainty quantification in such systems is generally achieved by means of sensitivity analyses in which one characterizes the variability with the uncertain kinetic parameters of the first statistical moments of model predictions. In this work, we propose an original global sensitivity analysis method where the parametric and inherent variability sources are both treated through Sobol's decomposition of the variance into contributions from arbitrary subset of uncertain parameters and stochastic reaction channels. The conceptual development only assumes that the inherent and parametric sources are independent, and considers the Poisson processes in the random-time-change representation of the state dynamics as the fundamental objects governing the inherent stochasticity. A sampling algorithm is proposed to perform the global sensitivity analysis, and to estimate the partial variances and sensitivity indices characterizing the importance of the various sources of variability and their interactions. The birth-death and Schlögl models are used to illustrate both the implementation of the algorithm and the richness of the proposed analysis method. The output of the proposed sensitivity analysis is also contrasted with a local derivative-based sensitivity analysis method classically used for this type of systems.

  9. On the robust optimization to the uncertain vaccination strategy problem

    SciTech Connect

    Chaerani, D. Anggriani, N. Firdaniza

    2014-02-21

    In order to prevent an epidemic of infectious diseases, the vaccination coverage needs to be minimized and also the basic reproduction number needs to be maintained below 1. This means that as we get the vaccination coverage as minimum as possible, thus we need to prevent the epidemic to a small number of people who already get infected. In this paper, we discuss the case of vaccination strategy in term of minimizing vaccination coverage, when the basic reproduction number is assumed as an uncertain parameter that lies between 0 and 1. We refer to the linear optimization model for vaccination strategy that propose by Becker and Starrzak (see [2]). Assuming that there is parameter uncertainty involved, we can see Tanner et al (see [9]) who propose the optimal solution of the problem using stochastic programming. In this paper we discuss an alternative way of optimizing the uncertain vaccination strategy using Robust Optimization (see [3]). In this approach we assume that the parameter uncertainty lies within an ellipsoidal uncertainty set such that we can claim that the obtained result will be achieved in a polynomial time algorithm (as it is guaranteed by the RO methodology). The robust counterpart model is presented.

  10. Control of multivehicle systems in the presence of uncertain dynamics

    NASA Astrophysics Data System (ADS)

    Yucelen, Tansel; Johnson, Eric N.

    2013-09-01

    In this paper, we present a cooperative control architecture for high-order multivehicle systems having non-identical nonlinear uncertain dynamics. The proposed methodology consists of a local cooperative controller and a vehicle-level controller for each vehicle. The former controller receives the relative output measurements of the neighbouring vehicles in order to solve a containment problem formulated on a leader-follower framework. Specifically, the leaders generate trajectories in which the vehicles (followers) converge to the convex hull formed by those of the leaders. For a special case with one leader, this controller synchronises the output of the vehicles with the output of the leader. The latter controller receives the internal-state measurements for suppressing the nonlinear uncertain dynamics of the vehicle by using a decentralised adaptive control approach. The interaction topology between vehicles is described by undirected graphs and extensions to directed graphs are further discussed. The stability and convergence properties of the proposed cooperative control architecture are analysed by using the results from linear algebra and the Lyapunov theory. Several numerical examples are provided to demonstrate the efficacy of the proposed cooperative control architecture.

  11. Robust Stabilization of Uncertain Systems Based on Energy Dissipation Concepts

    NASA Technical Reports Server (NTRS)

    Gupta, Sandeep

    1996-01-01

    Robust stability conditions obtained through generalization of the notion of energy dissipation in physical systems are discussed in this report. Linear time-invariant (LTI) systems which dissipate energy corresponding to quadratic power functions are characterized in the time-domain and the frequency-domain, in terms of linear matrix inequalities (LMls) and algebraic Riccati equations (ARE's). A novel characterization of strictly dissipative LTI systems is introduced in this report. Sufficient conditions in terms of dissipativity and strict dissipativity are presented for (1) stability of the feedback interconnection of dissipative LTI systems, (2) stability of dissipative LTI systems with memoryless feedback nonlinearities, and (3) quadratic stability of uncertain linear systems. It is demonstrated that the framework of dissipative LTI systems investigated in this report unifies and extends small gain, passivity, and sector conditions for stability. Techniques for selecting power functions for characterization of uncertain plants and robust controller synthesis based on these stability results are introduced. A spring-mass-damper example is used to illustrate the application of these methods for robust controller synthesis.

  12. Very low noise AC/DC power supply systems for large detector arrays.

    PubMed

    Arnaboldi, C; Baù, A; Carniti, P; Cassina, L; Giachero, A; Gotti, C; Maino, M; Passerini, A; Pessina, G

    2015-12-01

    In this work, we present the first part of the power supply system for the CUORE and LUCIFER arrays of bolometric detectors. For CUORE, it consists of AC/DC commercial power supplies (0-60 V output) followed by custom DC/DC modules (48 V input, ±5 V to ±13.5 V outputs). Each module has 3 floating and independently configurable output voltages. In LUCIFER, the AC/DC + DC/DC stages are combined into a commercial medium-power AC/DC source. At the outputs of both setups, we introduced filters with the aim of lowering the noise and to protect the following stages from high voltage spikes that can be generated by the energy stored in the cables after the release of accidental short circuits. Output noise is very low, as required: in the 100 MHz bandwidth the RMS level is about 37 μV(RMS) (CUORE setup) and 90 μV(RMS) (LUCIFER setup) at a load of 7 A, with a negligible dependence on the load current. Even more importantly, high frequency switching disturbances are almost completely suppressed. The efficiency of both systems is above 85%. Both systems are completely programmable and monitored via CAN bus (optically coupled).

  13. Silicon carbide DC-DC multilevel Cuk converter

    NASA Astrophysics Data System (ADS)

    Almalaq, Yasser; Alateeq, Ayoob; Matin, Mohammad

    2016-09-01

    In this paper, DC-DC multilevel cuk converter using silicon carbide (SiC) Components is presented. Cuk converter gives output voltage with negative polarity. This topology is useful for applications require high gain with limitation on duty cycle. The gain of the design can be enhanced by increasing the number of multiplier level (N). This relation between the gain and the number of levels is the major advantage of this multilevel cuk converter. In the proposed cuk converter, a single SiC MOSFET, 2N-1 SiC schottky diodes, 2N capacitors, 2 inductors, and single input voltage are used to supply a load with negative polarity. 300V input voltage, 50KHz switching frequency, and 75% duty cycle are the main parameters used in the design. The output parameters are 3KW power and -5.7 KV voltage. Because this design can be used in applications which temperature plays a critical role, the relation between increasing temperature and output voltage and power are tested. The design is simulated using LTspice software and the results are discussed.

  14. Arcing on dc power systems

    NASA Technical Reports Server (NTRS)

    Moores, Greg; Heller, R. P.; Sutanto, Surja; Dugal-Whitehead, Norma R.

    1992-01-01

    Unexpected and undesirable arcing on dc power systems can produce hazardous situations aboard space flights. The potential for fire and shock might exist in a situation where there is a broken conductor, a loose power connection, or a break in the insulation of the power cable. Such arcing has been found to be reproducible in a laboratory environment. Arcing tests show that the phenomena can last for several seconds and yet be undetectable by present protection schemes used in classical power relaying and remote power controller applications. This paper characterizes the arcing phenomena and suggests future research that is needed.

  15. [Testing the automobile driver in cases of uncertain qualification prognosis].

    PubMed

    Bode, H J

    1989-05-01

    The qualification of a person to drive a motor vehicle is the presupposition for the required permission. The prognosis on future human behaviour, which is indispensible for a judgement on such a qualification, is difficult. Only in a few of these cases a clear "good"-prognosis or "bad"-prognosis can be found out. Frequently only an "uncertain"-prognosis is to be justified as a matter of fact. It is only to be said by the regulations of law, whether in cases of uncertain qualification prognosis the driver's licence should be given or denied or whether a driver's licence already given should be withdrawn or not. Starting points for theory and dogmatics on prognosis-decisions due to law and orientated in the knowledge of empiric sciences are to be found in administrative law as well as in criminal law. For example: penal regulations which call for prognosis should be interpreted in the manner that as a sanction (only to be imposed in cases of "bad"-prognosis) the milder measure is to be used at first. Only after an unsuccessful attempt with this milder measure it is allowed to take a more incisive measure (Frisch). In planning law the dilemma with prognosis should be overcome by reflexive feedback within the scope of a new type of procedural law, which would make a process of learning and evaluation possible and enforcable. From these starting points common legal principles on a "test-method" can be developed, which may be used in cases of "uncertain"-prognosis. Such a test-method may help for example to decide on execution relaxations due to the Law on Execution of the Sentence (OLG Celle). The decree on driver's licences on probation (valid since 1.11.1986) contains the most extensive regulations concerning the application of test-methods within driver's licences law. The solution of the problem shown there should be extended: Not only the first driver's licence should only be given on probation but also a renewed one. Even motorists coming conspicuous after the

  16. "Model age-based" and "copy when uncertain" biases in children's social learning of a novel task.

    PubMed

    Wood, Lara A; Harrison, Rachel A; Lucas, Amanda J; McGuigan, Nicola; Burdett, Emily R R; Whiten, Andrew

    2016-10-01

    Theoretical models of social learning predict that individuals can benefit from using strategies that specify when and whom to copy. Here the interaction of two social learning strategies, model age-based biased copying and copy when uncertain, was investigated. Uncertainty was created via a systematic manipulation of demonstration efficacy (completeness) and efficiency (causal relevance of some actions). The participants, 4- to 6-year-old children (N=140), viewed both an adult model and a child model, each of whom used a different tool on a novel task. They did so in a complete condition, a near-complete condition, a partial demonstration condition, or a no-demonstration condition. Half of the demonstrations in each condition incorporated causally irrelevant actions by the models. Social transmission was assessed by first responses but also through children's continued fidelity, the hallmark of social traditions. Results revealed a bias to copy the child model both on first response and in continued interactions. Demonstration efficacy and efficiency did not affect choice of model at first response but did influence solution exploration across trials, with demonstrations containing causally irrelevant actions decreasing exploration of alternative methods. These results imply that uncertain environments can result in canalized social learning from specific classes of model.

  17. Block clustering based on difference of convex functions (DC) programming and DC algorithms.

    PubMed

    Le, Hoai Minh; Le Thi, Hoai An; Dinh, Tao Pham; Huynh, Van Ngai

    2013-10-01

    We investigate difference of convex functions (DC) programming and the DC algorithm (DCA) to solve the block clustering problem in the continuous framework, which traditionally requires solving a hard combinatorial optimization problem. DC reformulation techniques and exact penalty in DC programming are developed to build an appropriate equivalent DC program of the block clustering problem. They lead to an elegant and explicit DCA scheme for the resulting DC program. Computational experiments show the robustness and efficiency of the proposed algorithm and its superiority over standard algorithms such as two-mode K-means, two-mode fuzzy clustering, and block classification EM.

  18. Power Strategy in DC/DC Converters to Increase Efficiency of Electrical Stimulators.

    PubMed

    Aqueveque, Pablo; Acuña, Vicente; Saavedra, Francisco; Debelle, Adrien; Lonys, Laurent; Julémont, Nicolas; Huberland, François; Godfraind, Carmen; Nonclercq, Antoine

    2016-06-13

    Power efficiency is critical for electrical stimulators. Battery life of wearable stimulators and wireless power transmission in implanted systems are common limiting factors. Boost DC/DC converters are typically needed to increase the supply voltage of the output stage. Traditionally, boost DC/DC converters are used with fast control to regulate the supply voltage of the output. However, since stimulators are acting as current sources, such voltage regulation is not needed. Banking on this, this paper presents a DC/DC conversion strategy aiming to increase power efficiency. It compares, in terms of efficiency, the traditional use of boost converters to two alternatives that could be implemented in future hardware designs.

  19. Using uncertain data from body-worn sensors to gain insight into type 1 diabetes

    PubMed Central

    Heintzman, Nathaniel

    2016-01-01

    The amount of observational data available for research is growing rapidly with the rise of electronic health records and patient-generated data. However, these data bring new challenges, as data collected outside controlled environments and generated for purposes other than research may be error-prone, biased, or systematically missing. Analysis of these data requires methods that are robust to such challenges, yet methods for causal inference currently only handle uncertainty at the level of causal relationships – rather than variables or specific observations. In contrast, we develop a new approach for causal inference from time series data that allows uncertainty at the level of individual data points, so that inferences depend more strongly on variables and individual observations that are more certain. In the limit, a completely uncertain variable will be treated as if it were not measured. Using simulated data we demonstrate that the approach is more accurate than the state of the art, making substantially fewer false discoveries. Finally, we apply the method to a unique set of data collected from 17 individuals with type 1 diabetes mellitus (T1DM) in free-living conditions over 72 h where glucose levels, insulin dosing, physical activity and sleep are measured using body-worn sensors. These data often have high rates of error that vary across time, but we are able to uncover the relationships such as that between anaerobic activity and hyperglycemia. Ultimately, better modeling of uncertainty may enable better translation of methods to free-living conditions, as well as better use of noisy and uncertain EHR data. PMID:27580935

  20. Using uncertain data from body-worn sensors to gain insight into type 1 diabetes.

    PubMed

    Heintzman, Nathaniel; Kleinberg, Samantha

    2016-10-01

    The amount of observational data available for research is growing rapidly with the rise of electronic health records and patient-generated data. However, these data bring new challenges, as data collected outside controlled environments and generated for purposes other than research may be error-prone, biased, or systematically missing. Analysis of these data requires methods that are robust to such challenges, yet methods for causal inference currently only handle uncertainty at the level of causal relationships - rather than variables or specific observations. In contrast, we develop a new approach for causal inference from time series data that allows uncertainty at the level of individual data points, so that inferences depend more strongly on variables and individual observations that are more certain. In the limit, a completely uncertain variable will be treated as if it were not measured. Using simulated data we demonstrate that the approach is more accurate than the state of the art, making substantially fewer false discoveries. Finally, we apply the method to a unique set of data collected from 17 individuals with type 1 diabetes mellitus (T1DM) in free-living conditions over 72h where glucose levels, insulin dosing, physical activity and sleep are measured using body-worn sensors. These data often have high rates of error that vary across time, but we are able to uncover the relationships such as that between anaerobic activity and hyperglycemia. Ultimately, better modeling of uncertainty may enable better translation of methods to free-living conditions, as well as better use of noisy and uncertain EHR data.

  1. Artificial bias typically neglected in comparisons of uncertain atmospheric data

    NASA Astrophysics Data System (ADS)

    Pitkänen, Mikko R. A.; Mikkonen, Santtu; Lehtinen, Kari E. J.; Lipponen, Antti; Arola, Antti

    2016-09-01

    Publications in atmospheric sciences typically neglect biases caused by regression dilution (bias of the ordinary least squares line fitting) and regression to the mean (RTM) in comparisons of uncertain data. We use synthetic observations mimicking real atmospheric data to demonstrate how the biases arise from random data uncertainties of measurements, model output, or satellite retrieval products. Further, we provide examples of typical methods of data comparisons that have a tendency to pronounce the biases. The results show, that data uncertainties can significantly bias data comparisons due to regression dilution and RTM, a fact that is known in statistics but disregarded in atmospheric sciences. Thus, we argue that often these biases are widely regarded as measurement or modeling errors, for instance, while they in fact are artificial. It is essential that atmospheric and geoscience communities become aware of and consider these features in research.

  2. Modern medicine and the "uncertain body": from corporeality to hyperreality?

    PubMed

    Williams, S J

    1997-10-01

    This paper (re)considers the role of medical technology at three interrelated levels: first, the extent to which medical technology renders our bodies increasingly "uncertain" at the turn of the century; second, the analytical purchase which the notion of the (medical) cyborg provides regarding contemporary forms of human embodiment; and finally, at a broader level, the issues this raises in relation to a (late) modernist or postmodernist reading of contemporary medical practice. Key themes here include the plastic body, the bionic body, communal/interchangeable bodies, (genetically) engineered/ chosen bodies, and virtual bodies. The paper concludes with a critical appraisal of these themes and issues, arguing for a late modernist position on medical technology as both a positive and negative rationalising force, and a "life political agenda" in which the "all-too-human" quality of human nature is seen as inviolable.

  3. Design of Distributed Engine Control Systems with Uncertain Delay

    PubMed Central

    Li, Yanxi; Sun, Xu

    2016-01-01

    Future gas turbine engine control systems will be based on distributed architecture, in which, the sensors and actuators will be connected to the controllers via a communication network. The performance of the distributed engine control (DEC) is dependent on the network performance. This study introduces a distributed control system architecture based on a networked cascade control system (NCCS). Typical turboshaft engine-distributed controllers are designed based on the NCCS framework with a H∞ output feedback under network-induced time delays and uncertain disturbances. The sufficient conditions for robust stability are derived via the Lyapunov stability theory and linear matrix inequality approach. Both numerical and hardware-in-loop simulations illustrate the effectiveness of the presented method. PMID:27669005

  4. Design of Distributed Engine Control Systems with Uncertain Delay.

    PubMed

    Liu, Xiaofeng; Li, Yanxi; Sun, Xu

    Future gas turbine engine control systems will be based on distributed architecture, in which, the sensors and actuators will be connected to the controllers via a communication network. The performance of the distributed engine control (DEC) is dependent on the network performance. This study introduces a distributed control system architecture based on a networked cascade control system (NCCS). Typical turboshaft engine-distributed controllers are designed based on the NCCS framework with a H∞ output feedback under network-induced time delays and uncertain disturbances. The sufficient conditions for robust stability are derived via the Lyapunov stability theory and linear matrix inequality approach. Both numerical and hardware-in-loop simulations illustrate the effectiveness of the presented method.

  5. Dynamical analysis of uncertain neural networks with multiple time delays

    NASA Astrophysics Data System (ADS)

    Arik, Sabri

    2016-02-01

    This paper investigates the robust stability problem for dynamical neural networks in the presence of time delays and norm-bounded parameter uncertainties with respect to the class of non-decreasing, non-linear activation functions. By employing the Lyapunov stability and homeomorphism mapping theorems together, a new delay-independent sufficient condition is obtained for the existence, uniqueness and global asymptotic stability of the equilibrium point for the delayed uncertain neural networks. The condition obtained for robust stability establishes a matrix-norm relationship between the network parameters of the neural system, which can be easily verified by using properties of the class of the positive definite matrices. Some constructive numerical examples are presented to show the applicability of the obtained result and its advantages over the previously published corresponding literature results.

  6. Probabilistic confidence for decisions based on uncertain reliability estimates

    NASA Astrophysics Data System (ADS)

    Reid, Stuart G.

    2013-05-01

    Reliability assessments are commonly carried out to provide a rational basis for risk-informed decisions concerning the design or maintenance of engineering systems and structures. However, calculated reliabilities and associated probabilities of failure often have significant uncertainties associated with the possible estimation errors relative to the 'true' failure probabilities. For uncertain probabilities of failure, a measure of 'probabilistic confidence' has been proposed to reflect the concern that uncertainty about the true probability of failure could result in a system or structure that is unsafe and could subsequently fail. The paper describes how the concept of probabilistic confidence can be applied to evaluate and appropriately limit the probabilities of failure attributable to particular uncertainties such as design errors that may critically affect the dependability of risk-acceptance decisions. This approach is illustrated with regard to the dependability of structural design processes based on prototype testing with uncertainties attributable to sampling variability.

  7. Minimax design of neural net controllers for highly uncertain plants.

    PubMed

    Sebald, A V; Schlenzig, J

    1994-01-01

    This paper discusses the use of evolutionary programming (EP) for computer-aided design and testing of neural controllers applied to problems in which the system to be controlled is highly uncertain. Examples include closed-loop control of drug infusion and integrated control of HVAC/lighting/utility systems in large multi-use buildings. The method is described in detail and applied to a modified Cerebellar Model Arithmetic Computer (CMAC) neural network regulator for systems with unknown time delays. The design and testing problem is viewed as a game, in that the controller is chosen with a minimax criterion i.e., minimize the loss associated with its use on the worst possible plant. The technique permits analysis of neural strategies against a set of feasible plants. This yields both the best choice of control parameters and identification of that plant which is most difficult for the best controller to handle.

  8. Stability of uncertain systems. Ph.D. Thesis

    NASA Technical Reports Server (NTRS)

    Blankenship, G. L.

    1971-01-01

    The asymptotic properties of feedback systems are discussed, containing uncertain parameters and subjected to stochastic perturbations. The approach is functional analytic in flavor and thereby avoids the use of Markov techniques and auxiliary Lyapunov functionals characteristic of the existing work in this area. The results are given for the probability distributions of the accessible signals in the system and are proved using the Prohorov theory of the convergence of measures. For general nonlinear systems, a result similar to the small loop-gain theorem of deterministic stability theory is given. Boundedness is a property of the induced distributions of the signals and not the usual notion of boundedness in norm. For the special class of feedback systems formed by the cascade of a white noise, a sector nonlinearity and convolution operator conditions are given to insure the total boundedness of the overall feedback system.

  9. Setting priorities for exploration of uncertain water security outcomes

    NASA Astrophysics Data System (ADS)

    Jakeman, A. J.; Guillaume, J. H.; Kelly, R. A.

    2013-12-01

    Water security and over-allocation of surface and groundwater are key policy issues worldwide. The management of these issues can be approached through evaluation of the system-wide outcomes of water supply and demand scenarios. Integrated modelling can support this evaluation. This presentation makes use of a model developed for the Namoi catchment, part of the Murray-Darling Basin, Australia. The model identifies social, economic and environmental trade-offs under various water policy decisions and climate variations. The integrated model is composed of a hydrological model, a social model of likely behaviours of farmers, an ecological model of hydrological suitability, a farm decision (economic) model and a crop production model. Each of these components and their inputs are uncertain, which potentially leads to uncertainty in predicted outcomes. These uncertain outcomes can be explored by varying the model's assumptions about the system and exogeneous variables. This presentation presents and illustrates a simple risk-based process for setting initial priorities on what variations of models should be explored first. Firstly, identify the conclusions that the user is interested in drawing and the consequences if the wrong conclusions are drawn. Secondly, create a modular view of the model to understand which parts can be changed to account for uncertainty. Thirdly, elicit from the user, the modeller and other stakeholders the combinations of changes to the model that they believe are most likely to change the conclusion. The modeller may draw on both their expert opinion and computational techniques. The variations of models that should be explored first are those that carry the greatest risk, i.e. that are most likely to change a conclusion and which have the greatest consequences if that conclusion is changed. This exploration should be approached iteratively, as initial steps may help identify other conclusions of greater importance, gaps in the modular view

  10. How Much DC Power is Necessary

    DTIC Science & Technology

    2010-04-01

    must transform essentially all of the available AC power to DC, including all of the power for the ship propulsion drive. This approach by the...in Fig. 1 convert the AC source power to DC and energize the associated DC busses. At the power levels anticipated, i.e., for ship propulsion load...for a ship propulsion application. We begin by assuming that the variable frequency power electronics associated with the rotor will only deliver

  11. Active dc filter for HVDC systems

    SciTech Connect

    Zhang, W. ); Asplund, G.

    1994-01-01

    This article is a case history of the installation of active dc filters for high-performance, low-cost harmonics filtering at the Lindome converter station in the Konti-Skan 2 HVDC transmission link between Denmark and Sweden. The topics of the article include harmonics, interference, and filters, Lindome active dc filter, active dc filter design, digital signal processor, control scheme, protection and fault monitoring, and future applications.

  12. Chaos control for the output-constrained system by using adaptive dynamic surface technology and application to the brushless DC motor

    SciTech Connect

    Luo, Shaohua; Hou, Zhiwei; Chen, Zhong

    2015-12-15

    In this paper, chaos control is proposed for the output- constrained system with uncertain control gain and time delay and is applied to the brushless DC motor. Using the dynamic surface technology, the controller overcomes the repetitive differentiation of backstepping and boundedness hypothesis of pre-determined control gain by incorporating radial basis function neural network and adaptive technology. The tangent barrier Lyapunov function is employed for time-delay chaotic system to prevent constraint violation. It is proved that the proposed control approach can guarantee asymptotically stable in the sense of uniformly ultimate boundedness without constraint violation. Finally, the effectiveness of the proposed approach is demonstrated on the brushless DC motor example.

  13. Chaos control for the output-constrained system by using adaptive dynamic surface technology and application to the brushless DC motor

    NASA Astrophysics Data System (ADS)

    Luo, Shaohua; Hou, Zhiwei; Chen, Zhong

    2015-12-01

    In this paper, chaos control is proposed for the output- constrained system with uncertain control gain and time delay and is applied to the brushless DC motor. Using the dynamic surface technology, the controller overcomes the repetitive differentiation of backstepping and boundedness hypothesis of pre-determined control gain by incorporating radial basis function neural network and adaptive technology. The tangent barrier Lyapunov function is employed for time-delay chaotic system to prevent constraint violation. It is proved that the proposed control approach can guarantee asymptotically stable in the sense of uniformly ultimate boundedness without constraint violation. Finally, the effectiveness of the proposed approach is demonstrated on the brushless DC motor example.

  14. DC circuits: II. Identification of foothold ideas in DC circuits

    NASA Astrophysics Data System (ADS)

    John, lgnatius; Allie, Saalih

    2017-01-01

    This is the second part of a broader investigation which explores the reasons behind the contextual variations in student responses at a fine-grained level. In the previous article (John 2017 Eur. J. Phys. 38 015701) it was established that the students’ responses are highly context dependent at a fine-grained level. This article presents the reason for the contextual variations of student responses from their free written responses. The result indicates that students who are being triggered by the productive resources during the engagement with the task will arrive at the correct (canonical) conclusion and those triggered by the unproductive resources will arrive at an incorrect conclusion. We identified the productive foothold ideas in a simple DC circuit with a single resistive element.

  15. Delta Clipper-Experimental (DC-X)

    NASA Technical Reports Server (NTRS)

    1995-01-01

    Pictured here is a DC-XA Reusable Launch Vehicle (RLV) prototype concept with an RLV logo. The Delta Clipper-Experimental (DC-X) was originally developed by McDornell Douglas for the Department of Defense (DOD). The DC-XA is a single-stage-to-orbit, vertical takeoff/vertical landing, launch vehicle concept, whose development is geared to significantly reduce launch costs and will provide a test bed for NASA Reusable Launch Vehicle (RLV) technology as the Delta Clipper-Experimental Advanced (DC-XA).

  16. Evaluation of underground dc transmission systems

    NASA Astrophysics Data System (ADS)

    1982-03-01

    Progress in a program for evaluating underground dc transmission systems is reported. A basic load flow model was developed for a large ac power system. This model will be adjusted to produce representations for 4000, 8000, and 12,000 MW energy park. Load flow conditions for dc lines are being calculated. The stability of ac and dc are being examined. Short circuit duties are being calculated. Load flow computer runs are being made to demonstrate the suitability of developed ac and dc options.

  17. Simultaneous distribution of AC and DC power

    DOEpatents

    Polese, Luigi Gentile

    2015-09-15

    A system and method for the transport and distribution of both AC (alternating current) power and DC (direct current) power over wiring infrastructure normally used for distributing AC power only, for example, residential and/or commercial buildings' electrical wires is disclosed and taught. The system and method permits the combining of AC and DC power sources and the simultaneous distribution of the resulting power over the same wiring. At the utilization site a complementary device permits the separation of the DC power from the AC power and their reconstruction, for use in conventional AC-only and DC-only devices.

  18. Effect of Antioxidants on DC Tree and Grounded DC Tree in XLPE

    NASA Astrophysics Data System (ADS)

    Kawanami, Hiroshi; Komatsu, Isao; Sekii, Yasuo; Saito, Mitsugu; Sugi, Kazuyuki

    To study the effects of antioxidants on the initiation of the DC tree and the grounded DC tree, experiments were conducted using XLPE specimens containing phenolic and sulfur type antioxidants. Experimental results showed that sulfur type antioxidants in XLPE have the effect of increasing inception voltages of both the DC tree and the grounded DC tree. Based on results of those experiments, the mechanism of increase in the inception voltage of the DC tree and the grounded DC tree by antioxidants was examined along with the mechanism of polarity effects on those trees. Results showed a promotional effect of charge injection from a needle electrode by antioxidants, which are responsible for the increased inception voltages of the DC tree. Charge trapping by antioxidants explains the increase of inception voltages of the grounded DC tree.

  19. 76 FR 52225 - Airworthiness Directives; The Boeing Company Model DC-9-81 (MD-81), DC-9-82 (MD-82), DC-9-83 (MD...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-22

    ... Model DC-9-81 (MD- 81), DC-9-82 (MD-82), DC-9-83 (MD-83), DC-9-87 (MD-87), and MD-88 Airplanes AGENCY... Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590. FOR FURTHER INFORMATION... ADs (b) None. Applicability (c) This AD applies to The Boeing Company Model DC-9-81 (MD-81),...

  20. Synchronization transmission of spatiotemporal chaotic signal in the uncertain time-varying network

    NASA Astrophysics Data System (ADS)

    Lü, Ling; Chen, Liansong; Han, Changhui; Ge, Lianjun; Gao, Liyu

    2017-02-01

    In this paper, a new method is presented for the synchronization transmission of spatiotemporal chaotic signal in the uncertain time-varying network. By designing a special function to construct the Lyapunov function of the network, it is sure that the uncertain time-varying network can effectively synchronize the spatiotemporal chaotic signal generated by the synchronization target. At the same time, we also design the identification laws of uncertain parameters and the adaptive laws of the time-varying coupling matrix elements. Especially in our work, the nodes of the uncertain time-varying network and the synchronization target are different. Obviously, this research has the reference value for the application fields.

  1. Amodal Completion in Bonobos

    ERIC Educational Resources Information Center

    Nagasaka, Yasuo; Brooks, Daniel I.; Wasserman, Edward A.

    2010-01-01

    We trained two bonobos to discriminate among occluded, complete, and incomplete stimuli. The occluded stimulus comprised a pair of colored shapes, one of which appeared to occlude the other. The complete and incomplete stimuli involved the single shape that appeared to have been partially covered in the occluded stimulus; the complete stimulus…

  2. Beyond attachment: Roles of DC-SIGN in dengue virus infection.

    PubMed

    Liu, Ping; Ridilla, Marc; Patel, Pratik; Betts, Laurie; Gallichotte, Emily; Shahidi, Lidea; Thompson, Nancy L; Jacobson, Ken

    2017-04-01

    Dendritic cell-specific intercellular adhesion molecule-3-grabbing non-integrin (DC-SIGN), a C-type lectin expressed on the plasma membrane by human immature dendritic cells, is a receptor for numerous viruses including Ebola, SARS and dengue. A controversial question has been whether DC-SIGN functions as a complete receptor for both binding and internalization of dengue virus (DENV) or whether it is solely a cell surface attachment factor, requiring either hand-off to another receptor or a co-receptor for internalization. To examine this question, we used 4 cell types: human immature dendritic cells and NIH3T3 cells expressing either wild-type DC-SIGN or 2 internalization-deficient DC-SIGN mutants, in which either the 3 cytoplasmic internalization motifs are silenced by alanine substitutions or the cytoplasmic region is truncated. Using confocal and super-resolution imaging and high content single particle tracking, we investigated DENV binding, DC-SIGN surface transport, endocytosis, as well as cell infectivity. DC-SIGN was found colocalized with DENV inside cells suggesting hand-off at the plasma membrane to another receptor did not occur. Moreover, all 3 DC-SIGN molecules on NIH3T3 cells supported cell infection. These results imply the involvement of a co-receptor because cells expressing the internalization-deficient mutants could still be infected.

  3. High voltage DC power supply

    DOEpatents

    Droege, T.F.

    1989-12-19

    A high voltage DC power supply having a first series resistor at the output for limiting current in the event of a short-circuited output, a second series resistor for sensing the magnitude of output current, and a voltage divider circuit for providing a source of feedback voltage for use in voltage regulation is disclosed. The voltage divider circuit is coupled to the second series resistor so as to compensate the feedback voltage for a voltage drop across the first series resistor. The power supply also includes a pulse-width modulated control circuit, having dual clock signals, which is responsive to both the feedback voltage and a command voltage, and also includes voltage and current measuring circuits responsive to the feedback voltage and the voltage developed across the second series resistor respectively. 7 figs.

  4. High voltage DC power supply

    DOEpatents

    Droege, Thomas F.

    1989-01-01

    A high voltage DC power supply having a first series resistor at the output for limiting current in the event of a short-circuited output, a second series resistor for sensing the magnitude of output current, and a voltage divider circuit for providing a source of feedback voltage for use in voltage regulation is disclosed. The voltage divider circuit is coupled to the second series resistor so as to compensate the feedback voltage for a voltage drop across the first series resistor. The power supply also includes a pulse-width modulated control circuit, having dual clock signals, which is responsive to both the feedback voltage and a command voltage, and also includes voltage and current measuring circuits responsive to the feedback voltage and the voltage developed across the second series resistor respectively.

  5. HOx Photochemistry during DC3

    NASA Astrophysics Data System (ADS)

    Ren, X.; Mao, J.; Zhang, L.; Miller, D.; Brune, W. H.

    2013-12-01

    Measurements of OH, HO2 and OH reactivity were made as part of a much larger measurement suite from the NASA DC-8 aircraft during the Deep Convective Clouds and Chemistry (DC3) study in summer 2012. This mission, which was conducted over central North American region to investigate the impact of deep convection on upper tropospheric composition and chemistry, provides us an excellent opportunity to test oxidation chemistry in convection throughout the troposphere. Measured HOx are compared with the calculations using a box model that was constrained to in-situ measurements of long-lived chemicals. In general both measured OH and HO2 agree well with the model calculations within the measurement uncertainties. On average, the model tends to under-predict HO2 at low altitudes. No significant NO dependence was found for the observed-to-modeled OH and HO2 ratios, except the ratios are slightly less than unity when NO levels were greater than 1 ppbv indicating model over-prediction. The measured OH reactivity agrees generally well with the calculated OH reactivity using the measured OH reactants, with the measured OH reactivity higher than the calculated OH reactivity by about a factor of 1.2. We attribute this to possible missing OH reactants in the measurements. HOx budget analysis shows that the main HOx production was dominated by the ozone photolysis followed by the O(1D)+H2O reaction throughout the troposphere with small contributions from the photolysis of formaldehyde and hydrogen peroxide. The main HOx loss was the HO2+HO2 and HO2+RO2 reactions. The calculated net ozone production rates were observed to be about 1 ppb/h-1 between 10-12 km and 5 ppb h-1 below 1.5 km and were close to zero between 4-8 km. HOx behaviors under different conditions are is discussed.

  6. Dynamic Uncertain Causality Graph for Knowledge Representation and Probabilistic Reasoning: Directed Cyclic Graph and Joint Probability Distribution.

    PubMed

    Zhang, Qin

    2015-07-01

    Probabilistic graphical models (PGMs) such as Bayesian network (BN) have been widely applied in uncertain causality representation and probabilistic reasoning. Dynamic uncertain causality graph (DUCG) is a newly presented model of PGMs, which can be applied to fault diagnosis of large and complex industrial systems, disease diagnosis, and so on. The basic methodology of DUCG has been previously presented, in which only the directed acyclic graph (DAG) was addressed. However, the mathematical meaning of DUCG was not discussed. In this paper, the DUCG with directed cyclic graphs (DCGs) is addressed. In contrast, BN does not allow DCGs, as otherwise the conditional independence will not be satisfied. The inference algorithm for the DUCG with DCGs is presented, which not only extends the capabilities of DUCG from DAGs to DCGs but also enables users to decompose a large and complex DUCG into a set of small, simple sub-DUCGs, so that a large and complex knowledge base can be easily constructed, understood, and maintained. The basic mathematical definition of a complete DUCG with or without DCGs is proved to be a joint probability distribution (JPD) over a set of random variables. The incomplete DUCG as a part of a complete DUCG may represent a part of JPD. Examples are provided to illustrate the methodology.

  7. Similarity estimators for irregular and age-uncertain time series

    NASA Astrophysics Data System (ADS)

    Rehfeld, K.; Kurths, J.

    2014-01-01

    Paleoclimate time series are often irregularly sampled and age uncertain, which is an important technical challenge to overcome for successful reconstruction of past climate variability and dynamics. Visual comparison and interpolation-based linear correlation approaches have been used to infer dependencies from such proxy time series. While the first is subjective, not measurable and not suitable for the comparison of many data sets at a time, the latter introduces interpolation bias, and both face difficulties if the underlying dependencies are nonlinear. In this paper we investigate similarity estimators that could be suitable for the quantitative investigation of dependencies in irregular and age-uncertain time series. We compare the Gaussian-kernel-based cross-correlation (gXCF, Rehfeld et al., 2011) and mutual information (gMI, Rehfeld et al., 2013) against their interpolation-based counterparts and the new event synchronization function (ESF). We test the efficiency of the methods in estimating coupling strength and coupling lag numerically, using ensembles of synthetic stalagmites with short, autocorrelated, linear and nonlinearly coupled proxy time series, and in the application to real stalagmite time series. In the linear test case, coupling strength increases are identified consistently for all estimators, while in the nonlinear test case the correlation-based approaches fail. The lag at which the time series are coupled is identified correctly as the maximum of the similarity functions in around 60-55% (in the linear case) to 53-42% (for the nonlinear processes) of the cases when the dating of the synthetic stalagmite is perfectly precise. If the age uncertainty increases beyond 5% of the time series length, however, the true coupling lag is not identified more often than the others for which the similarity function was estimated. Age uncertainty contributes up to half of the uncertainty in the similarity estimation process. Time series irregularity

  8. Similarity estimators for irregular and age uncertain time series

    NASA Astrophysics Data System (ADS)

    Rehfeld, K.; Kurths, J.

    2013-09-01

    Paleoclimate time series are often irregularly sampled and age uncertain, which is an important technical challenge to overcome for successful reconstruction of past climate variability and dynamics. Visual comparison and interpolation-based linear correlation approaches have been used to infer dependencies from such proxy time series. While the first is subjective, not measurable and not suitable for the comparison of many datasets at a time, the latter introduces interpolation bias, and both face difficulties if the underlying dependencies are nonlinear. In this paper we investigate similarity estimators that could be suitable for the quantitative investigation of dependencies in irregular and age uncertain time series. We compare the Gaussian-kernel based cross correlation (gXCF, Rehfeld et al., 2011) and mutual information (gMI, Rehfeld et al., 2013) against their interpolation-based counterparts and the new event synchronization function (ESF). We test the efficiency of the methods in estimating coupling strength and coupling lag numerically, using ensembles of synthetic stalagmites with short, autocorrelated, linear and nonlinearly coupled proxy time series, and in the application to real stalagmite time series. In the linear test case coupling strength increases are identified consistently for all estimators, while in the nonlinear test case the correlation-based approaches fail. The lag at which the time series are coupled is identified correctly as the maximum of the similarity functions in around 60-55% (in the linear case) to 53-42% (for the nonlinear processes) of the cases when the dating of the synthetic stalagmite is perfectly precise. If the age uncertainty increases beyond 5% of the time series length, however, the true coupling lag is not identified more often than the others for which the similarity function was estimated. Age uncertainty contributes up to half of the uncertainty in the similarity estimation process. Time series irregularity

  9. Congenital complete heart block.

    PubMed Central

    Agarwala, B.; Sheikh, Z.; Cibils, L. A.

    1996-01-01

    Congenital complete heart block in utero has become diagnosed more frequently with the clinical use of fetal echocardiography. The fetus with complete heart block may remain asymptomatic or may develop congestive heart failure. Congenital complete heart block is more frequently seen in infants of mothers with systemic lupus erythematosus, both clinically manifested and subclinical systemic lupus erythematosus with positive antibodies (SS-A and SS-B antibodies). At birth, the neonate with complete heart block may remain asymptomatic and may not require a pacemaker to increase the heart rate. The indications for a pacemaker in neonates with complete heart block have been discussed. Both in-utero and neonatal management of congenital complete heart block are discussed to manage congestive heart failure in a fetus. Four patients with congenital complete heart block are presented covering a broad spectrum of clinical presentation, diagnosis, and management both in the fetal and neonatal period. Images Figure 1 PMID:8961692

  10. ALA 2010: Where to Eat in DC

    ERIC Educational Resources Information Center

    Library Journal, 2010

    2010-01-01

    As host to visitors and transplants from around the world, Washington, DC, benefits from the constant infusion of different cultures. Although most neighborhoods lack a unified culinary flavor, make no mistake: DC is a city of distinctive areas, each with its own style, ensuring that hungry American Library Association (ALA) 2010 conference…

  11. Dual wound dc brush motor gearhead

    NASA Technical Reports Server (NTRS)

    Henson, Barrie W.

    1986-01-01

    The design requirements, the design, development tests and problems, the qualification and life test and the findings of the strip examination of a dual wound DC brushed motor gearhead are described. It is the only space qualified dual wound dc brushed motor gearhead in Europe.

  12. Modeling of DC spacecraft power systems

    NASA Technical Reports Server (NTRS)

    Berry, F. C.

    1995-01-01

    Future spacecraft power systems must be capable of supplying power to various loads. This delivery of power may necessitate the use of high-voltage, high-power dc distribution systems to transmit power from the source to the loads. Using state-of-the-art power conditioning electronics such as dc-dc converters, complex series and parallel configurations may be required at the interface between the source and the distribution system and between the loads and the distribution system. This research will use state-variables to model and simulate a dc spacecraft power system. Each component of the dc power system will be treated as a multiport network, and a state model will be written with the port voltages as the inputs. The state model of a component will be solved independently from the other components using its state transition matrix. A state-space averaging method is developed first in general for any dc-dc switching converter, and then demonstrated in detail for the particular case of the boost power stage. General equations for both steady-state (dc) and dynamic effects (ac) are obtained, from which important transfer functions are derived and applied to a special case of the boost power stage.

  13. DC-based magnetic field controller

    DOEpatents

    Kotter, Dale K.; Rankin, Richard A.; Morgan, John P,.

    1994-01-01

    A magnetic field controller for laboratory devices and in particular to dc operated magnetic field controllers for mass spectrometers, comprising a dc power supply in combination with improvements to a hall probe subsystem, display subsystem, preamplifier, field control subsystem, and an output stage.

  14. Close-Range Gunfire around DC Schools

    ERIC Educational Resources Information Center

    Bieler, Sam; La Vigne, Nancy

    2014-01-01

    This report examines the incidence of gunfire as measured by gunshot detection technology using data from the 2011-2012 school year. It finds that a disproportionate volume of gunfire happened near a small share of DC schools. About half of DC schools covered by gunshot detection sensors are in close proximity to gunfire, and four schools were…

  15. DC-based magnetic field controller

    DOEpatents

    Kotter, D.K.; Rankin, R.A.; Morgan, J.P.

    1994-05-31

    A magnetic field controller is described for laboratory devices and in particular to dc operated magnetic field controllers for mass spectrometers, comprising a dc power supply in combination with improvements to a Hall probe subsystem, display subsystem, preamplifier, field control subsystem, and an output stage. 1 fig.

  16. DC KIDS COUNT e-Databook Indicators

    ERIC Educational Resources Information Center

    DC Action for Children, 2012

    2012-01-01

    This report presents indicators that are included in DC Action for Children's 2012 KIDS COUNT e-databook, their definitions and sources and the rationale for their selection. The indicators for DC KIDS COUNT represent a mix of traditional KIDS COUNT indicators of child well-being, such as the number of children living in poverty, and indicators of…

  17. Allocating conservation resources between areas where persistence of a species is uncertain.

    PubMed

    McDonald-Madden, Eve; Chadès, Iadine; McCarthy, Michael A; Linkie, Matthew; Possingham, Hugh P

    2011-04-01

    Research on the allocation of resources to manage threatened species typically assumes that the state of the system is completely observable; for example whether a species is present or not. The majority of this research has converged on modeling problems as Markov decision processes (MDP), which give an optimal strategy driven by the current state of the system being managed. However, the presence of threatened species in an area can be uncertain. Typically, resource allocation among multiple conservation areas has been based on the biggest expected benefit (return on investment) but fails to incorporate the risk of imperfect detection. We provide the first decision-making framework for confronting the trade-off between information and return on investment, and we illustrate the approach for populations of the Sumatran tiger (Panthera tigris sumatrae) in Kerinci Seblat National Park. The problem is posed as a partially observable Markov decision process (POMDP), which extends MDP to incorporate incomplete detection and allows decisions based on our confidence in particular states. POMDP has previously been used for making optimal management decisions for a single population of a threatened species. We extend this work by investigating two populations, enabling us to explore the importance of variation in expected return on investment between populations on how we should act. We compare the performance of optimal strategies derived assuming complete (MDP) and incomplete (POMDP) observability. We find that uncertainty about the presence of a species affects how we should act. Further, we show that assuming full knowledge of a species presence will deliver poorer strategic outcomes than if uncertainty about a species status is explicitly considered. MDP solutions perform up to 90% worse than the POMDP for highly cryptic species, and they only converge in performance when we are certain of observing the species during management: an unlikely scenario for many

  18. Lynch Syndrome Limbo: Patient Understanding of Variants of Uncertain Significance.

    PubMed

    Solomon, Ilana; Harrington, Elizabeth; Hooker, Gillian; Erby, Lori; Axilbund, Jennifer; Hampel, Heather; Semotiuk, Kara; Blanco, Amie; Klein, William M P; Giardiello, Francis; Leonard, Lori

    2017-01-26

    Providers and patients encounter challenges related to the management of Variants of Unknown Significance (VUS). A VUS introduces new counseling dilemmas for the understanding and psychosocial impact of uncertain genetic test results. This descriptive study uses Mishel's theory of uncertainty in illness to explore the experience of individuals who have received a VUS as part of the genetic testing process. Semi-structured interviews were conducted with 27 adult individuals who received a VUS for Lynch syndrome mismatch repair genes between 2002 and 2013. The interviews were transcribed and analyzed. Most individuals recalled their result and perceived various types of uncertainty associated with their VUS. Half of the participants appraised their variant as a danger and implemented coping strategies to reduce the threat of developing cancer. Mobilizing strategies to reduce their risk included vigilant cancer surveillance, information seeking and notifying relatives. The majority of participants were unaware of the possibility of a VUS before receiving their result and expected reclassification over time. These results provide insight into the ways healthcare providers can support patients who receive VUS for Lynch syndrome. Findings also provide direction for future work that can further explicate the impact of receiving a VUS.

  19. Estimation of uncertain material parameters using modal test data

    SciTech Connect

    Veers, P.S.; Laird, D.L.; Carne, T.G.; Sagartz, M.J.

    1997-11-01

    Analytical models of wind turbine blades have many uncertainties, particularly with composite construction where material properties and cross-sectional dimension may not be known or precisely controllable. In this paper the authors demonstrate how modal testing can be used to estimate important material parameters and to update and improve a finite-element (FE) model of a prototype wind turbine blade. An example of prototype blade is used here to demonstrate how model parameters can be identified. The starting point is an FE model of the blade, using best estimates for the material constants. Frequencies of the lowest fourteen modes are used as the basis for comparisons between model predictions and test data. Natural frequencies and mode shapes calculated with the FE model are used in an optimal test design code to select instrumentation (accelerometer) and excitation locations that capture all the desired mode shapes. The FE model is also used to calculate sensitivities of the modal frequencies to each of the uncertain material parameters. These parameters are estimated, or updated, using a weighted least-squares technique to minimize the difference between test frequencies and predicted results. Updated material properties are determined for axial, transverse, and shear moduli in two separate regions of the blade cross section: in the central box, and in the leading and trailing panels. Static FE analyses are then conducted with the updated material parameters to determine changes in effective beam stiffness and buckling loads.

  20. Simple Coupling of Reactor Physics Effects and Uncertain Nuances

    SciTech Connect

    Bays, Samuel

    2012-08-27

    The "Simple Coupling of Reactor Physics Effects and Uncertain Nuances" (SCORPEUN) code is a simple r-z 1-group neutron diffusion code where each r-mesh is coupled to a single-flow-channel model that represents all flow-channels in that r-mesh. This 1-D model assesses q=m*Cp*deletaT for each z-mesh in that channel. This flow channel model is then coupled to a simple 1-D heat conduction model for ascertaining the peak center-line fuel temperature in a hypothetical pin assigned to that flow channel. The code has property lookup capability for water, Na, Zirc, HT9, metalic fuel, oxide fuel, etc. It has linear interpolation features for micro-scopic cross-sections with respect to coolant density and fuel temperature. ***This last feature has not been fully tested and may need development***. The interpolated microscopic cross-sections are then combined (using the water density from the T/H calculation) to generate macroscopic diffusion coefficient, removal cross-section and nu-sigmaF for each r-z mesh of the neutron diffusion code.

  1. Merging strategic and tactical planning in dynamic and uncertain environments

    SciTech Connect

    Bonissone, P.P.; Dutta, S.; Wood, N.C.

    1994-06-01

    This paper presents a new approach to planning in dynamic and uncertain environments. Planning is viewed as a process in which an agent`s long term goals are transformed into short term tasks and objectives, given the agent`s strategy and the context of planning. The developed model allows for a dynamic balance between long term strategic planning and short term tactical planning. The notion of a strategy hierarchy is introduced to explicitly represent the process of strategy formulation and refinement. A combination of rules and plan scripts is used. Rules are used for representing domain knowledge and reasoning about strategic choices. Plan scripts are used for representing specific tasks and objectives. The uncertainty calculi of RUM/PRIMO (2), (6) are used for supporting reasoning under uncertainty. In the proposed model, it is also possible to achieve a seamless integration of case-based reasoning into the planning process. These ideas have been implemented in a system called MARS, which plans in the financial domain of mergers and acquisitions. 63 refs.

  2. Distributed Control of Uncertain Systems using Superpositions of Linear operators

    PubMed Central

    Sanger, Terence D.

    2011-01-01

    Control in the natural environment is difficult in part because of uncertainty in the effect of actions. Uncertainty can be due to added motor or sensory noise, unmodeled dynamics, or quantization of sensory feedback. Biological systems are faced with further difficulties, since control must be performed by networks of cooperating neurons and neural subsystems. Here, we propose a new mathematical framework for modeling and simulation of distributed control systems operating in an uncertain environment. Stochastic Differential Operators can be derived from the stochastic differential equation describing a system, and they map the current state density into the differential of the state density. Unlike discrete-time Markov update operators, stochastic differential operators combine linearly for a large class of linear and nonlinear systems, and therefore the combined effects of multiple controllable and uncontrollable subsystems can be predicted. Design using these operators yields systems whose statistical behavior can be specified throughout state space. The relationship to Bayesian estimation and discrete-time Markov processes is described. PMID:21521040

  3. Bayesian multiple-source localization in an uncertain ocean environment.

    PubMed

    Dosso, Stan E; Wilmut, Michael J

    2011-06-01

    This paper considers simultaneous localization of multiple acoustic sources when properties of the ocean environment (water column and seabed) are poorly known. A Bayesian formulation is developed in which the environmental parameters, noise statistics, and locations and complex strengths (amplitudes and phases) of multiple sources are considered to be unknown random variables constrained by acoustic data and prior information. Two approaches are considered for estimating source parameters. Focalization maximizes the posterior probability density (PPD) over all parameters using adaptive hybrid optimization. Marginalization integrates the PPD using efficient Markov-chain Monte Carlo methods to produce joint marginal probability distributions for source ranges and depths, from which source locations are obtained. This approach also provides quantitative uncertainty analysis for all parameters, which can aid in understanding of the inverse problem and may be of practical interest (e.g., source-strength probability distributions). In both approaches, closed-form maximum-likelihood expressions for source strengths and noise variance at each frequency allow these parameters to be sampled implicitly, substantially reducing the dimensionality and difficulty of the inversion. Examples are presented of both approaches applied to single- and multi-frequency localization of multiple sources in an uncertain shallow-water environment, and a Monte Carlo performance evaluation study is carried out.

  4. Augmented nonlinear differentiator design and application to nonlinear uncertain systems.

    PubMed

    Shao, Xingling; Liu, Jun; Li, Jie; Cao, Huiliang; Shen, Chong; Zhang, Xiaoming

    2017-03-01

    In this paper, an augmented nonlinear differentiator (AND) based on sigmoid function is developed to calculate the noise-less time derivative under noisy measurement condition. The essential philosophy of proposed AND in achieving high attenuation of noise effect is established by expanding the signal dynamics with extra state variable representing the integrated noisy measurement, then with the integral of measurement as input, the augmented differentiator is formulated to improve the estimation quality. The prominent advantages of the present differentiation technique are: (i) better noise suppression ability can be achieved without appreciable delay; (ii) the improved methodology can be readily extended to construct augmented high-order differentiator to obtain multiple derivatives. In addition, the convergence property and robustness performance against noises are investigated via singular perturbation theory and describing function method, respectively. Also, comparison with several classical differentiators is given to illustrate the superiority of AND in noise suppression. Finally, the robust control problems of nonlinear uncertain systems, including a numerical example and a mass spring system, are addressed to demonstrate the effectiveness of AND in precisely estimating the disturbance and providing the unavailable differential estimate to implement output feedback based controller.

  5. An Inadequacy Formulation for an Uncertain Flamelet Model

    NASA Astrophysics Data System (ADS)

    Sondak, David; Oliver, Todd; Simmons, Chris; Moser, Robert

    2016-11-01

    We report progress on the development of an uncertain flamelet library for use in non-premixed turbulent combustion. A stochastic inadequacy operator is generalized from previous work and is now used to incorporate uncertainties in chemical reaction mechanisms in a flamelet model. The original form of the inadequacy operator was designed to enforce positivity of chemical species concentrations and conservation of species while representing inadequacies in reduced chemical mechanisms. As a first step towards generalization, we are exploring temperature dependent modifications to the inadequacy operator. The temperature dependence helps ensure that the operator is inactive in the absence of chemical reactions and becomes active only after ignition. A Bayesian inverse problem is used to calibrate the stochastic operator on a hydrogen-oxygen zero-dimensional reactor and to infer model parameters, and their uncertainties, from data obtained via a detailed chemical mechanism. The inferred model parameters are then propagated through a laminar, non-premixed, counterflow hydrogen-oxygen flame. Temperature and species profiles at various scalar dissipation rates are compared to those predicted from a five-reaction reduced model and the detailed model.

  6. Distributed control of uncertain systems using superpositions of linear operators.

    PubMed

    Sanger, Terence D

    2011-08-01

    Control in the natural environment is difficult in part because of uncertainty in the effect of actions. Uncertainty can be due to added motor or sensory noise, unmodeled dynamics, or quantization of sensory feedback. Biological systems are faced with further difficulties, since control must be performed by networks of cooperating neurons and neural subsystems. Here, we propose a new mathematical framework for modeling and simulation of distributed control systems operating in an uncertain environment. Stochastic differential operators can be derived from the stochastic differential equation describing a system, and they map the current state density into the differential of the state density. Unlike discrete-time Markov update operators, stochastic differential operators combine linearly for a large class of linear and nonlinear systems, and therefore the combined effects of multiple controllable and uncontrollable subsystems can be predicted. Design using these operators yields systems whose statistical behavior can be specified throughout state-space. The relationship to Bayesian estimation and discrete-time Markov processes is described.

  7. 75 FR 446 - In the Matter of Certain DC-DC Controllers and Products; Notice of Investigation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-05

    ... Doc No: E9-31252] INTERNATIONAL TRADE COMMISSION [Inv. No. 337-TA-698] In the Matter of Certain DC--DC... sale for importation, and the sale within the United States after importation of certain DC--DC... Commission, 500 E Street, SW., Room 112, Washington, DC 20436, telephone 202-205-2000. Hearing...

  8. DC/DC Power Converter for Super-Capacitor Supplied by Electric Power Splitter

    NASA Astrophysics Data System (ADS)

    Haubert, T.; Mindl, P.

    The aim of the article is design of DC/DC converter and discussing of problematic supply using electric power splitter. The electric power splitter with AC/DC converter is source for the DC/DC converter, which is dedicated for charging and discharging of hybrid car drive super-capacitor energy storage. The electric power splitter is synchronous machine with two rotating parts. First rotor contains permanent magnet and the second rotor contains three-phase windings. The amplitude of output voltage depends on difference between first and second rotor speed. The main role of the DC/DC converter is to optimize energy content in super-capacitor storage used to acceleration and deceleration driving period of the passenger car with hybrid electric vehicle (HEV) drive system using electric power splitter.

  9. A High Voltage Ratio and Low Ripple Interleaved DC-DC Converter for Fuel Cell Applications

    PubMed Central

    Chang, Long-Yi; Chao, Kuei-Hsiang; Chang, Tsang-Chih

    2012-01-01

    This paper proposes a high voltage ratio and low ripple interleaved boost DC-DC converter, which can be used to reduce the output voltage ripple. This converter transfers the low DC voltage of fuel cell to high DC voltage in DC link. The structure of the converter is parallel with two voltage-doubler boost converters by interleaving their output voltages to reduce the voltage ripple ratio. Besides, it can lower the current stress for the switches and inductors in the system. First, the PSIM software was used to establish a proton exchange membrane fuel cell and a converter circuit model. The simulated and measured results of the fuel cell output characteristic curve are made to verify the correctness of the established simulation model. In addition, some experimental results are made to validate the effectiveness in improving output voltage ripple of the proposed high voltage ratio interleaved boost DC-DC converters. PMID:23365536

  10. 40 CFR 725.15 - Determining applicability when microorganism identity or use is confidential or uncertain.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... microorganism identity or use is confidential or uncertain. 725.15 Section 725.15 Protection of Environment... PROCESSES FOR MICROORGANISMS General Provisions and Applicability § 725.15 Determining applicability when microorganism identity or use is confidential or uncertain. (a) Consulting EPA. Persons intending to...

  11. 40 CFR 725.15 - Determining applicability when microorganism identity or use is confidential or uncertain.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... microorganism identity or use is confidential or uncertain. 725.15 Section 725.15 Protection of Environment... PROCESSES FOR MICROORGANISMS General Provisions and Applicability § 725.15 Determining applicability when microorganism identity or use is confidential or uncertain. (a) Consulting EPA. Persons intending to...

  12. 40 CFR 725.15 - Determining applicability when microorganism identity or use is confidential or uncertain.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... microorganism identity or use is confidential or uncertain. 725.15 Section 725.15 Protection of Environment... PROCESSES FOR MICROORGANISMS General Provisions and Applicability § 725.15 Determining applicability when microorganism identity or use is confidential or uncertain. (a) Consulting EPA. Persons intending to...

  13. 40 CFR 725.15 - Determining applicability when microorganism identity or use is confidential or uncertain.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... microorganism identity or use is confidential or uncertain. 725.15 Section 725.15 Protection of Environment... PROCESSES FOR MICROORGANISMS General Provisions and Applicability § 725.15 Determining applicability when microorganism identity or use is confidential or uncertain. (a) Consulting EPA. Persons intending to...

  14. 40 CFR 725.15 - Determining applicability when microorganism identity or use is confidential or uncertain.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... microorganism identity or use is confidential or uncertain. 725.15 Section 725.15 Protection of Environment... PROCESSES FOR MICROORGANISMS General Provisions and Applicability § 725.15 Determining applicability when microorganism identity or use is confidential or uncertain. (a) Consulting EPA. Persons intending to...

  15. Passivity-Based Adaptive Hybrid Synchronization of a New Hyperchaotic System with Uncertain Parameters

    PubMed Central

    2012-01-01

    We investigate the adaptive hybrid synchronization problem for a new hyperchaotic system with uncertain parameters. Based on the passivity theory and the adaptive control theory, corresponding controllers and parameter estimation update laws are proposed to achieve hybrid synchronization between two identical uncertain hyperchaotic systems with different initial values, respectively. Numerical simulation indicates that the presented methods work effectively. PMID:23365538

  16. 75 FR 60371 - Requirements of a Statement Disclosing Uncertain Tax Positions; Correction

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-30

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF THE TREASURY Internal Revenue Service 26 CFR Part 1 RIN 1545-BJ54 Requirements of a Statement Disclosing Uncertain Tax... schedule disclosing uncertain tax positions related to the tax return as required by the IRS. FOR...

  17. 75 FR 54802 - Requirement of a Statement Disclosing Uncertain Tax Positions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-09

    ... Internal Revenue Service 26 CFR Part 1 RIN 1545-BJ54 Requirement of a Statement Disclosing Uncertain Tax... corporations to file a schedule disclosing uncertain tax positions related to the tax return as required by the... Tax Regulations (26 CFR part 1) under section 6012 relating to the returns of income corporations...

  18. Passivity-based adaptive hybrid synchronization of a new hyperchaotic system with uncertain parameters.

    PubMed

    Zhou, Xiaobing; Fan, Zhangbiao; Zhou, Dongming; Cai, Xiaomei

    2012-01-01

    We investigate the adaptive hybrid synchronization problem for a new hyperchaotic system with uncertain parameters. Based on the passivity theory and the adaptive control theory, corresponding controllers and parameter estimation update laws are proposed to achieve hybrid synchronization between two identical uncertain hyperchaotic systems with different initial values, respectively. Numerical simulation indicates that the presented methods work effectively.

  19. The analysis and design of brushless D.C. motors

    NASA Astrophysics Data System (ADS)

    Benarous, Maamar

    practical results indicates that the complete modelling can be achieved using this method. The mathematical models of both Star, and Delta connected brushless DC machines are presented, and a complete model of the machine inverter system is built for both cases. The work is accomplished by the use of the Matlab analogue simulation toolbox, Simulink, and the simulation program calculates the electrical performances of both machines under steady state. The results obtained are compared to the experimental data, and a comparison between both machines is presented. A brushless DC motor using an insulated iron core material is presented, and analysed using 2D finite element analysis. The newly constructed machine is also tested and compared to the conventional version.

  20. Pulsed-DC DBD Plasma Actuators

    NASA Astrophysics Data System (ADS)

    Duong, Alan; McGowan, Ryan; Disser, Katherine; Corke, Thomas; Matlis, Eric

    2016-11-01

    A new powering system for dielectric barrier discharge (DBD) plasma actuators that utilizes a pulsed-DC waveform is presented. The plasma actuator arrangement is identical to most typical AC-DBD designs with staggered electrodes that are separated by a dielectric insulator. However instead of an AC voltage input to drive the actuator, the pulsed-DC utilizes a DC voltage source. The DC source is supplied to both electrodes, and remains constant in time for the exposed electrode. The DC source for the covered electrode is periodically grounded for very short instants and then allowed to rise to the source DC level. This process results in a plasma actuator body force that is significantly larger than that with an AC-DBD at the same voltages. The important characteristics used in optimizing the pulsed-DC plasma actuators are presented. Time-resolved velocity measurements near the actuator are further used to understand the underlying physics of its operation compared to the AC-DBD. Supported by NASA Glenn RC.

  1. Latino College Completion: Maine

    ERIC Educational Resources Information Center

    Excelencia in Education (NJ1), 2012

    2012-01-01

    In 2009, Excelencia in Education launched the Ensuring America's Future initiative to inform, organize, and engage leaders in a tactical plan to increase Latino college completion. An executive summary of Latino College Completion in 50 states synthesizes information on 50 state factsheets and builds on the national benchmarking guide. Each…

  2. Latino College Completion: Connecticut

    ERIC Educational Resources Information Center

    Excelencia in Education (NJ1), 2012

    2012-01-01

    In 2009, Excelencia in Education launched the Ensuring America's Future initiative to inform, organize, and engage leaders in a tactical plan to increase Latino college completion. An executive summary of Latino College Completion in 50 states synthesizes information on 50 state factsheets and builds on the national benchmarking guide. Each…

  3. Latino College Completion: California

    ERIC Educational Resources Information Center

    Excelencia in Education (NJ1), 2012

    2012-01-01

    In 2009, Excelencia in Education launched the Ensuring America's Future initiative to inform, organize, and engage leaders in a tactical plan to increase Latino college completion. An executive summary of Latino College Completion in 50 states synthesizes information on 50 state factsheets and builds on the national benchmarking guide. Each…

  4. Latino College Completion: Ohio

    ERIC Educational Resources Information Center

    Excelencia in Education (NJ1), 2012

    2012-01-01

    In 2009, Excelencia in Education launched the Ensuring America's Future initiative to inform, organize, and engage leaders in a tactical plan to increase Latino college completion. An executive summary of Latino College Completion in 50 states synthesizes information on 50 state factsheets and builds on the national benchmarking guide. Each…

  5. Latino College Completion: Massachusetts

    ERIC Educational Resources Information Center

    Excelencia in Education (NJ1), 2012

    2012-01-01

    In 2009, Excelencia in Education launched the Ensuring America's Future initiative to inform, organize, and engage leaders in a tactical plan to increase Latino college completion. An executive summary of Latino College Completion in 50 states synthesizes information on 50 state factsheets and builds on the national benchmarking guide. Each…

  6. Latino College Completion: Florida

    ERIC Educational Resources Information Center

    Excelencia in Education (NJ1), 2012

    2012-01-01

    In 2009, Excelencia in Education launched the Ensuring America's Future initiative to inform, organize, and engage leaders in a tactical plan to increase Latino college completion. An executive summary of Latino College Completion in 50 states synthesizes information on 50 state factsheets and builds on the national benchmarking guide. Each…

  7. Latino College Completion: Iowa

    ERIC Educational Resources Information Center

    Excelencia in Education (NJ1), 2012

    2012-01-01

    In 2009, Excelencia in Education launched the Ensuring America's Future initiative to inform, organize, and engage leaders in a tactical plan to increase Latino college completion. An executive summary of Latino College Completion in 50 states synthesizes information on 50 state factsheets and builds on the national benchmarking guide. Each…

  8. Latino College Completion: Hawaii

    ERIC Educational Resources Information Center

    Excelencia in Education (NJ1), 2012

    2012-01-01

    In 2009, Excelencia in Education launched the Ensuring America's Future initiative to inform, organize, and engage leaders in a tactical plan to increase Latino college completion. An executive summary of Latino College Completion in 50 states synthesizes information on 50 state factsheets and builds on the national benchmarking guide. Each…

  9. Latino College Completion: Mississippi

    ERIC Educational Resources Information Center

    Excelencia in Education (NJ1), 2012

    2012-01-01

    In 2009, Excelencia in Education launched the Ensuring America's Future initiative to inform, organize, and engage leaders in a tactical plan to increase Latino college completion. An executive summary of Latino College Completion in 50 states synthesizes information on 50 state factsheets and builds on the national benchmarking guide. Each…

  10. Latino College Completion: Maryland

    ERIC Educational Resources Information Center

    Excelencia in Education (NJ1), 2012

    2012-01-01

    In 2009, Excelencia in Education launched the Ensuring America's Future initiative to inform, organize, and engage leaders in a tactical plan to increase Latino college completion. An executive summary of Latino College Completion in 50 states synthesizes information on 50 state factsheets and builds on the national benchmarking guide. Each…

  11. Latino College Completion: Montana

    ERIC Educational Resources Information Center

    Excelencia in Education (NJ1), 2012

    2012-01-01

    In 2009, Excelencia in Education launched the Ensuring America's Future initiative to inform, organize, and engage leaders in a tactical plan to increase Latino college completion. An executive summary of Latino College Completion in 50 states synthesizes information on 50 state factsheets and builds on the national benchmarking guide. Each…

  12. Latino College Completion: Nevada

    ERIC Educational Resources Information Center

    Excelencia in Education (NJ1), 2012

    2012-01-01

    In 2009, Excelencia in Education launched the Ensuring America's Future initiative to inform, organize, and engage leaders in a tactical plan to increase Latino college completion. An executive summary of Latino College Completion in 50 states synthesizes information on 50 state factsheets and builds on the national benchmarking guide. Each…

  13. Movement stability under uncertain internal models of dynamics.

    PubMed

    Crevecoeur, F; McIntyre, J; Thonnard, J-L; Lefèvre, P

    2010-09-01

    internal models are uncertain.

  14. Baseload coal investment decisions under uncertain carbon legislation.

    PubMed

    Bergerson, Joule A; Lave, Lester B

    2007-05-15

    More than 50% of electricity in the U.S. is generated by coal. The U.S. has large coal resources, the cheapest fuel in most areas. Coal fired power plants are likely to continue to provide much of U.S. electricity. However, the type of power plant that should be built is unclear. Technology can reduce pollutant discharges and capture and sequester the CO2 from coal-fired generation. The U.S. Energy Policy Act of 2005 provides incentives for large scale commercial deployment of Integrated Coal Gasification Combined Cycle (IGCC) systems (e.g., loan guarantees and project tax credits). This analysis examines whether a new coal plant should be Pulverized Coal (PC) or IGCC. Do stricter emissions standards (PM, SO2, NOx, Hg) justify the higher costs of IGCC over PC? How does potential future carbon legislation affect the decision to add carbon capture and storage (CCS) technology? Finally, can the impact of uncertain carbon legislation be minimized? We find that SO2, NOx, PM, and Hg emission standards would have to be far more stringent than twice current standards to justify the increased costs of the IGCC system. A C02 tax less than $29/ton would lead companies to continuing to choose PC, paying the tax for emitted CO2. The earlier a decision-maker believes the carbon tax will be imposed and the higher the tax, the more likely companies will choose IGCC w/CCS. Having government announce the date and level of a carbon tax would promote more sensible decisions, but government would have to use a tax or subsidy to induce companies to choose the technology that is best for society.

  15. Baseload coal investment decisions under uncertain carbon legislation

    SciTech Connect

    Joule A. Bergerson; Lester B. Lave

    2007-05-15

    More than 50% of electricity in the U.S. is generated by coal. The U.S. has large coal resources, the cheapest fuel in most areas. Coal fired power plants are likely to continue to provide much of U.S. electricity. However, the type of power plant that should be built is unclear. Technology can reduce pollutant discharges and capture and sequester the CO{sub 2} from coal-fired generation. The U.S. Energy Policy Act of 2005 provides incentives for large scale commercial deployment of Integrated Coal Gasification Combined Cycle (IGCC) systems (e.g., loan guarantees and project tax credits). This analysis examines whether a new coal plant should be pulverized coal (PC) or IGCC. Do stricter emissions standards (PM, SO{sub 2}, NOx, Hg) justify the higher costs of IGCC over PC? How does potential future carbon legislation affect the decision to add carbon capture and storage (CCS) technology? Finally, can the impact of uncertain carbon legislation be minimized? We find that SO{sub 2}, NOx, PM, and Hg emission standards would have to be far more stringent than twice current standards to justify the increased costs of the IGCC system. A CO{sub 2} tax less than $29/ton would lead companies to continuing to choose PC, paying the tax for emitted CO{sub 2}. The earlier a decision-maker believes the carbon tax will be imposed and the higher the tax, the more likely companies will choose IGCC with CCS. Having government announce the date and level of a carbon tax would promote more sensible decisions, but government would have to use a tax or subsidy to induce companies to choose the technology that is best for society. 14 refs., 6 figs., 4 tabs.

  16. Parameter Estimation for Groundwater Models under Uncertain Irrigation Data.

    PubMed

    Demissie, Yonas; Valocchi, Albert; Cai, Ximing; Brozovic, Nicholas; Senay, Gabriel; Gebremichael, Mekonnen

    2015-01-01

    The success of modeling groundwater is strongly influenced by the accuracy of the model parameters that are used to characterize the subsurface system. However, the presence of uncertainty and possibly bias in groundwater model source/sink terms may lead to biased estimates of model parameters and model predictions when the standard regression-based inverse modeling techniques are used. This study first quantifies the levels of bias in groundwater model parameters and predictions due to the presence of errors in irrigation data. Then, a new inverse modeling technique called input uncertainty weighted least-squares (IUWLS) is presented for unbiased estimation of the parameters when pumping and other source/sink data are uncertain. The approach uses the concept of generalized least-squares method with the weight of the objective function depending on the level of pumping uncertainty and iteratively adjusted during the parameter optimization process. We have conducted both analytical and numerical experiments, using irrigation pumping data from the Republican River Basin in Nebraska, to evaluate the performance of ordinary least-squares (OLS) and IUWLS calibration methods under different levels of uncertainty of irrigation data and calibration conditions. The result from the OLS method shows the presence of statistically significant (p < 0.05) bias in estimated parameters and model predictions that persist despite calibrating the models to different calibration data and sample sizes. However, by directly accounting for the irrigation pumping uncertainties during the calibration procedures, the proposed IUWLS is able to minimize the bias effectively without adding significant computational burden to the calibration processes.

  17. Variants of Uncertain Significance in BRCA Testing: Evaluation of Surgical Decisions, Risk Perception, and Cancer Distress

    PubMed Central

    Culver, J.O.; Brinkerhoff, C.D.; Clague, J.; Yang, K.; Singh, K.E.; Sand, S.R.; Weitzel, J.N.

    2013-01-01

    Studies suggest that patients carrying a BRCA variant of uncertain significance (VUS) may have lingering confusion concerning results interpretation. Counseling for uninformative BRCA-negative (UN) results is thought to be more straightforward, despite the fact that both results lead to similar methods of empiric cancer risk counseling. This study compared surgical choices and perceptions between 71 patients with VUS results and 714 patients with UN results. All patients underwent genetic counseling because of a personal or family history of breast or ovarian cancer between 1997 and 2010, and completed a two-year follow-up survey. Risk-reducing mastectomy rates in both groups were 7% (p=1.00) and risk-reducing oophorectomy rates were 5% and 3%, respectively (p=0.42). The VUS group reported less cancer distress reduction than the UN group (23.0% versus 35.8%, respectively, p=.043). Over 90% of both groups found the counseling process helpful. Overall, the study suggests that VUS results disclosed in genetic counseling did not cause excessive surgery or exaggerated cancer distress, though patients with a VUS found counseling somewhat less informative or reassuring. Future research on communication of VUS results, including pre-and post-test counseling, is essential for full realization of the potential for genomic medicine. PMID:23323793

  18. Minimum time search in uncertain dynamic domains with complex sensorial platforms.

    PubMed

    Lanillos, Pablo; Besada-Portas, Eva; Lopez-Orozco, Jose Antonio; de la Cruz, Jesus Manuel

    2014-08-04

    The minimum time search in uncertain domains is a searching task, which appears in real world problems such as natural disasters and sea rescue operations, where a target has to be found, as soon as possible, by a set of sensor-equipped searchers. The automation of this task, where the time to detect the target is critical, can be achieved by new probabilistic techniques that directly minimize the Expected Time (ET) to detect a dynamic target using the observation probability models and actual observations collected by the sensors on board the searchers. The selected technique, described in algorithmic form in this paper for completeness, has only been previously partially tested with an ideal binary detection model, in spite of being designed to deal with complex non-linear/non-differential sensorial models. This paper covers the gap, testing its performance and applicability over different searching tasks with searchers equipped with different complex sensors. The sensorial models under test vary from stepped detection probabilities to continuous/discontinuous differentiable/non-differentiable detection probabilities dependent on distance, orientation, and structured maps. The analysis of the simulated results of several static and dynamic scenarios performed in this paper validates the applicability of the technique with different types of sensor models.

  19. Minimum Time Search in Uncertain Dynamic Domains with Complex Sensorial Platforms

    PubMed Central

    Lanillos, Pablo; Besada-Portas, Eva; Lopez-Orozco, Jose Antonio; de la Cruz, Jesus Manuel

    2014-01-01

    The minimum time search in uncertain domains is a searching task, which appears in real world problems such as natural disasters and sea rescue operations, where a target has to be found, as soon as possible, by a set of sensor-equipped searchers. The automation of this task, where the time to detect the target is critical, can be achieved by new probabilistic techniques that directly minimize the Expected Time (ET) to detect a dynamic target using the observation probability models and actual observations collected by the sensors on board the searchers. The selected technique, described in algorithmic form in this paper for completeness, has only been previously partially tested with an ideal binary detection model, in spite of being designed to deal with complex non-linear/non-differential sensorial models. This paper covers the gap, testing its performance and applicability over different searching tasks with searchers equipped with different complex sensors. The sensorial models under test vary from stepped detection probabilities to continuous/discontinuous differentiable/non-differentiable detection probabilities dependent on distance, orientation, and structured maps. The analysis of the simulated results of several static and dynamic scenarios performed in this paper validates the applicability of the technique with different types of sensor models. PMID:25093345

  20. Reserve design for uncertain responses of coral reefs to climate change.

    PubMed

    Mumby, Peter J; Elliott, Ian A; Eakin, C Mark; Skirving, William; Paris, Claire B; Edwards, Helen J; Enríquez, Susana; Iglesias-Prieto, Roberto; Cherubin, Laurent M; Stevens, Jamie R

    2011-02-01

    Rising sea temperatures cause mass coral bleaching and threaten reefs worldwide. We show how maps of variations in thermal stress can be used to help manage reefs for climate change. We map proxies of chronic and acute thermal stress and develop evidence-based hypotheses for the future response of corals to each stress regime. We then incorporate spatially realistic predictions of larval connectivity among reefs of the Bahamas and apply novel reserve design algorithms to create reserve networks for a changing climate. We show that scales of larval dispersal are large enough to connect reefs from desirable thermal stress regimes into a reserve network. Critically, we find that reserve designs differ according to the anticipated scope for phenotypic and genetic adaptation in corals, which remains uncertain. Attempts to provide a complete reserve design that hedged against different evolutionary outcomes achieved limited success, which emphasises the importance of considering the scope for adaptation explicitly. Nonetheless, 15% of reserve locations were selected under all evolutionary scenarios, making them a high priority for early designation. Our approach allows new insights into coral holobiont adaptation to be integrated directly into an adaptive approach to management.

  1. Residual generation for fault detection and isolation in a class of uncertain nonlinear systems

    NASA Astrophysics Data System (ADS)

    Ma, Hong-Jun; Yang, Guang-Hong

    2013-02-01

    This article studies the problem of fault detection and isolation (FDI) for a class of uncertain nonlinear systems via a residual signal generated by a novel nonlinear adaptive observer. The considered faults are modelled by a set of time-varying vectors, in which a prescribed subset of faults are specially monitored and thus separable from the other faults. In the presence of Lipschitz-like nonlinearities and modelling uncertainties, the sensitivity of the residual signal to the monitored faults and its insensitivity to the other faults are rigorously analysed. Under a persistent excitation condition, the performances of the proposed fault diagnosis scheme, including the robustness to uncertainties, the quickness of estimation, the accuracy of estimation, the sensitivity to the monitored faults and the insensitivity to the complement faults, are quantified by a series of explicit design functions relevant to the observer parameters. It turns out that the number of faults which can be completely diagnosed is independent of the number of output sensors. A simulation example is given to illustrate the effectiveness of the proposed FDI method.

  2. High power density dc/dc converter: Selection of converter topology

    NASA Technical Reports Server (NTRS)

    Divan, Deepakraj M.

    1990-01-01

    The work involved in the identification and selection of a suitable converter topology is described. Three new dc/dc converter topologies are proposed: Phase-Shifted Single Active Bridge DC/DC Converter; Single Phase Dual Active Bridges DC/DC Converter; and Three Phase Dual Active Bridges DC/DC Converter (Topology C). The salient features of these topologies are: (1) All are minimal in structure, i.e., each consists of an input and output bridge, input and output filter and a transformer, all components essential for a high power dc/dc conversion process; (2) All devices of both the bridges can operate under near zero-voltage conditions, making possible a reduction of device switching losses and hence, an increase in switching frequency; (3) All circuits operate at a constant frequency, thus simplifying the task of the magnetic and filter elements; (4) Since, the leakage inductance of the transformer is used as the main current transfer element, problems associated with the diode reverse recovery are eliminated. Also, this mode of operation allows easy paralleling of multiple modules for extending the power capacity of the system; (5) All circuits are least sensitive to parasitic impedances, infact the parasitics are efficently utilized; and (6) The soft switching transitions, result in low electromagnetic interference. A detailed analysis of each topology was carried out. Based on the analysis, the various device and component ratings for each topology operating at an optimum point, and under the given specifications, are tabulated and discussed.

  3. Robust DC/DC converter control for polymer electrolyte membrane fuel cell application

    NASA Astrophysics Data System (ADS)

    Wang, Ya-Xiong; Yu, Duck-Hyun; Chen, Shi-An; Kim, Young-Bae

    2014-09-01

    This study investigates a robust controller in regulating the pulse width modulation (PWM) of a DC/DC converter for a polymer electrolyte membrane fuel cell (PEMFC) application. A significant variation in the output voltage of a PEMFC depends on the power requirement and prevents a PEMFC from directly connecting to a subsequent power bus. DC/DC converters are utilized to step-up or step-down voltage to match the subsequent power bus voltage. In this study, a full dynamic model, which includes a PEMFC and boost and buck DC/DC converters, is developed under MATLAB/Simulink environment for control. A robust PWM duty ratio control for the converters is designed using time delay control (TDC). This control enables state variables to accurately follow the dynamics of a reference model using time-delayed information of plant input and output information within a few sampling periods. To prove the superiority of the TDC performance, traditional proportional-integral control (PIC) and model predictive control (MPC) are designed and implemented, and the simulation results are compared. The efficacies of TDC for the PEMFC-fed PWM DC/DC converters are validated through experimental test results using a 100 W PEMFC as well as boost and buck DC/DC converters.

  4. Novel bidirectional DC-DC converters based on the three-state switching cell

    NASA Astrophysics Data System (ADS)

    da Silva Júnior, José Carlos; Robles Balestero, Juan Paulo; Lessa Tofoli, Fernando

    2016-05-01

    It is well known that there is an increasing demand for bidirectional DC-DC converters for applications that range from renewable energy sources to electric vehicles. Within this context, this work proposes novel DC-DC converter topologies that use the three-state switching cell (3SSC), whose well-known advantages over conventional existing structures are ability to operate at high current levels, while current sharing is maintained by a high frequency transformer; reduction of cost and dimensions of magnetics; improved distribution of losses, with consequent increase of global efficiency and reduction of cost associated to the need of semiconductors with lower current ratings. Three distinct topologies can be derived from the 3SSC: one DC-DC converter with reversible current characteristic able to operate in the first and second quadrants; one DC-DC converter with reversible voltage characteristic able to operate in the first and third quadrants and one DC-DC converter with reversible current and voltage characteristics able to operate in four quadrants. Only the topology with bidirectional current characteristic is analysed in detail in terms of the operating stages in both nonoverlapping and overlapping modes, while the design procedure of the power stage elements is obtained. In order to validate the theoretical assumptions, an experimental prototype is also implemented, so that relevant issues can be properly discussed.

  5. DC isolation and protection system and circuit

    NASA Technical Reports Server (NTRS)

    Wagner, Charles A. (Inventor); Kellogg, Gary V. (Inventor)

    1991-01-01

    A precision analog electronic circuit that is capable of sending accurate signals to an external device that has hostile electric characteristics, including the presence of very large common mode voltages. The circuit is also capable of surviving applications of normal mode overvoltages of up to 120 VAC/VDC for unlimited periods of time without damage or degradation. First, the circuit isolates the DC signal output from the computer. Means are then provided for amplifying the isolated DC signal. Further means are provided for stabilizing and protecting the isolating and amplifying means, and the isolated and amplified DC signal which is output to the external device, against overvoltages and overcurrents.

  6. Advanced DC/DC Converters Towards Higher Volumetric Efficiencies For Space Applications

    NASA Technical Reports Server (NTRS)

    Shaw, Harry; Shue, Jack; Liu, David; Wang, Bright; Plante, Jeanette

    2005-01-01

    A new emphasis on planetary exploration by NASA drives the need for small, high power DC/DC converters which are functionally modular. NASA GSFC and other government space organizations are supporting technology development in the DC/DC converter area to both meet new needs and to promote more sources of supply. New technologies which enable miniaturization such as embedded passive technologies and thermal management using high thermal conductivity materials are features of the new designs. Construction of some simple DC/DC converter core circuits using embedded components was found to be successful for increasing volumetric efficiency to 37 W/inch. The embedded passives were also able to perform satisfactorily in this application in cryogenic temperatures.

  7. Application handbook for a Standardized Control Module (SCM) for DC-DC converters, volume 1

    NASA Technical Reports Server (NTRS)

    Lee, F. C.; Mahmoud, M. F.; Yu, Y.

    1980-01-01

    The standardized control module (SCM) was developed for application in the buck, boost and buck/boost DC-DC converters. The SCM used multiple feedback loops to provide improved input line and output load regulation, stable feedback control system, good dynamic transient response and adaptive compensation of the control loop for changes in open loop gain and output filter time constraints. The necessary modeling and analysis tools to aid the design engineer in the application of the SCM to DC-DC Converters were developed. The SCM functional block diagram and the different analysis techniques were examined. The average time domain analysis technique was chosen as the basic analytical tool. The power stage transfer functions were developed for the buck, boost and buck/boost converters. The analog signal and digital signal processor transfer functions were developed for the three DC-DC Converter types using the constant on time, constant off time and constant frequency control laws.

  8. Nonlinear Phenomena and Resonant Parametric Perturbation Control in QR-ZCS Buck DC-DC Converters

    NASA Astrophysics Data System (ADS)

    Hsieh, Fei-Hu; Liu, Feng-Shao; Hsieh, Hui-Chang

    The purpose of this study is to investigate the chaotic phenomena and to control in current-mode controlled quasi-resonant zero-current-switching (QR-ZCS) DC-DC buck converters, and to present control of chaos by resonant parametric perturbation control methods. First of all, MATLAB/SIMULINK is used to derive a mathematical model for QR-ZCS DC-DC buck converters, and to simulate the converters to observe the waveform of output voltages, inductance currents and phase-plane portraits from the period-doubling bifurcation to chaos by changing the load resistances. Secondly, using resonant parametric perturbation control in QR-ZCS buck DC-DC converters, the simulation results of the chaotic converter form chaos state turn into stable state period 1, and improve ripple amplitudes of converters under the chaos, to verify the validity of the proposes method.

  9. DC-DC converters with reduced mass for trackers at the HL-LHC

    NASA Astrophysics Data System (ADS)

    Affolder, A.; Allongue, B.; Blanchot, G.; Faccio, F.; Fuentes, C.; Greenall, A.; Michelis, S.

    2011-11-01

    The development at CERN of low noise DC-DC converters for the powering of front-end systems enables the implementation of efficient powering schemes for the physics experiments at the HL-LHC. Recent tests made on the ATLAS short strip tracker modules confirm the full electromagnetic compatibility of the DC-DC converter prototypes with front-end detectors. The integration of the converters in the trackers front-ends needs to address also the material budget constraints. The impact of the DC-DC converters onto the material budget of the ATLAS tracker modules is discussed and mass reduction techniques are explored, leading to a compromise between electromagnetic compatibility and mass. Low mass shield implementations and Aluminum core inductors are proposed. Also, the impact on emitted noise due to a size reduction of critical components is discussed. Finally, material reduction techniques are discussed at the board layout and manufacturing levels.

  10. Test Results of Selected Commercial DC/DC Converters under Cryogenic Temperatures - A Digest

    NASA Technical Reports Server (NTRS)

    Patterson, Richard; Hammoud, Ahmad

    2010-01-01

    DC/DC converters are widely used in space power systems in the areas of power management and distribution, signal conditioning, and motor control. Design of DC/DC converters to survive cryogenic temperatures will improve the power system performance, simplify design, and reduce development and launch costs. In this work, the performance of nine COTS modular, low-tomedium power DC/DC converters was investigated under cryogenic temperatures. The converters were evaluated in terms of their output regulation, efficiency, and input and output currents. At a given temperature, these properties were obtained at various input voltages and at different load levels. A summary on the performance of the tested converters was given. More comprehensive testing and in-depth analysis of performance under long-term exposure to extreme temperatures are deemed necessary to establish the suitability of these and other devices for use in the harsh environment of space exploration missions.

  11. Power Strategy in DC/DC Converters to Increase Efficiency of Electrical Stimulators

    PubMed Central

    Aqueveque, Pablo; Acuña, Vicente; Saavedra, Francisco; Debelle, Adrien; Lonys, Laurent; Julémont, Nicolas; Huberland, François; Godfraind, Carmen; Nonclercq, Antoine

    2016-01-01

    Power efficiency is critical for electrical stimulators. Battery life of wearable stimulators and wireless power transmission in implanted systems are common limiting factors. Boost DC/DC converters are typically needed to increase the supply voltage of the output stage. Traditionally, boost DC/DC converters are used with fast control to regulate the supply voltage of the output. However, since stimulators are acting as current sources, such voltage regulation is not needed. Banking on this, this paper presents a DC/DC conversion strategy aiming to increase power efficiency. It compares, in terms of efficiency, the traditional use of boost converters to two alternatives that could be implemented in future hardware designs. PMID:27990232

  12. A SQUID series array dc current sensor

    NASA Astrophysics Data System (ADS)

    Beyer, J.; Drung, D.

    2008-09-01

    Superconducting quantum interference device (SQUID) sensors are used to sense changes in various physical quantities, which can be transformed into changes in the magnetic flux threading the SQUID loop. We have developed a novel SQUID array dc current sensor. The device is based on a series array of identical dc SQUIDs. An input signal current to be measured is coupled tightly but non-uniformly to the SQUID array elements. The input signal coupling to the individual array elements is chosen such that a single-valued, non-periodic overall voltage response is obtained. Flux offsets in the individual SQUIDs which would compromise the sensor voltage response are avoided or can be compensated. We present simulations and experimental results on the SQUID Array for Dc (SQUAD) current sensor current sensor performance. A dc current resolution of <1 nA in a measurement bandwidth of 0-25 Hz is achieved for an input inductance of LIn<3 nH.

  13. Tester periodically registers dc amplifier characteristics

    NASA Technical Reports Server (NTRS)

    Cree, D.; Wenzel, G. E.

    1966-01-01

    Motor-driven switcher-recorder periodically registers the zero drift and gain drift signals of a dc amplifier subjected to changes in environment. A time coding method is used since several measurements are shared on a single recorder trace.

  14. DC-8 Takeoff in Kiruna, Sweden

    NASA Video Gallery

    NASA is using a DC-8 aircraft as a flying science laboratory. The platform aircraft, based at NASA's Dryden Flight Research Center, Edwards, Calif., collects data for many experiments in support of...

  15. Uncertain nest fates in songbird studies and variation in Mayfield estimation

    USGS Publications Warehouse

    Manolis, J.C.; Andersen, D.E.; Cuthbert, F.J.

    2000-01-01

    Determining whether nesting attempts are successful can be difficult. Yet, current protocols for estimating nesting success do not address how uncertain nest fates should be handled. We examined the problem of nest-fate uncertainty as it relates to Mayfield estimation of nesting success and in analyses of factors that influence success. We used data from Minnesota to illustrate the potential effect of uncertain fate; 40% of Ovenbird (Seiurus aurocapillus; n = 127) nests and 30% of Least Flycatcher (Empidonax minimus; n = 144) nests had uncertain fates. How this uncertainty is incorporated into Mayfield estimates of success varied widely among researchers. In a survey of researchers who use the Mayfield method, 9 of 22 respondents (of 40 contacted) excluded nests with uncertain fate. Excluding uncertain fates is counter to how Mayfield first described his estimator and can result in severe downward bias. The remaining respondents (59%) included nests with uncertain fate but varied in how they terminated the exposure period. We developed a simulation model that calculated Mayfield estimates using different approaches and compared them with a known rate of nesting success. Magnitude of bias in Mayfield estimates varied considerably in our simulations. The approach with the least bias terminated exposure with the last observed active date for nests with uncertain fate, and with the midpoint between last observed active and first observed inactive dates for nests with known fate. In addition, information necessary to interpret and compare Mayfield estimates often is not reported. These values, including variance estimates and the period lengths used to estimate survival rates, should be reported with Mayfield estimates. Finally, nest fate is commonly used as a categorical variable in studies of factors affecting nesting success. In this approach, however, nests with uncertain fate must be excluded. An alternative approach is Cox regression, which incorporates nests with

  16. dc illusion and its experimental verification

    NASA Astrophysics Data System (ADS)

    Liu, Min; Lei Mei, Zhong; Ma, Xiang; Cui, Tie Jun

    2012-07-01

    Based on the transformation optics method, we propose a dc illusion device, which can transform a metallic object into a magnified dielectric object using anisotropic conducting materials. Utilizing the analogy between electric conductivities and resistor networks, we design and fabricate the device using metal film resistors. The practical measurement data agree very well with simulation results. The proposed dc illusion device is easy to process and measure, and thus has potential applications in various sectors.

  17. DC-8 MTP calibration for SOLVE-2

    NASA Technical Reports Server (NTRS)

    Mahoney, M. J.

    2003-01-01

    The Jet Propulsion Laboratory (JPL) Microwave Temperature Profiler (MTP) was the only instrument making temperature measurements at and below flight level on the DC-8 during the SOLVE-2 campaign. Many years of careful comparison of MTP measurements with radiosondes near the DC-8 flight track have shown that the flight level temperature can be determined to an accuracy of 0.2K relative to radiosondes.

  18. Brushless DC Motors, Velocity and Position Control of the Brushless DC Motor.

    DTIC Science & Technology

    1986-06-01

    DC motor was designed using the Hall effect sensors. In addition, the position control of the brushless DC motor was developed using an optical encoder to sense angular position changes and a microprocessor to provide the desired position control. A Pittman 5111 wdg 1 brushless DC motor was used for this study. The design of the digital tachometer and pulse width modulator for velocity control and the design of the Z-80 based microprocessor controller and software design are described in

  19. Robust finite-time stabilization of unified chaotic complex systems with certain and uncertain parameters

    NASA Astrophysics Data System (ADS)

    Liu, Ping

    2013-07-01

    This paper deals with the finite-time stabilization of unified chaotic complex systems with known and unknown parameters. Based on the finite-time stability theory, nonlinear control laws are presented to achieve finite-time chaos control of the determined and uncertain unified chaotic complex systems, respectively. The two controllers are simple, and one of the uncertain unified chaotic complex systems is robust. For the design of a finite-time controller on uncertain unified chaotic complex systems, only some of the unknown parameters need to be bounded. Simulation results for the chaotic complex Lorenz, Lü and Chen systems are presented to validate the design and analysis.

  20. A new synchronization tracking technique for uncertain discrete network with spatiotemporal chaos behaviors

    NASA Astrophysics Data System (ADS)

    Lü, Ling; Chen, Liansong; Bai, Suyuan; Li, Gang

    2016-10-01

    We propose a novel scheme to achieve synchronization tracking of uncertain discrete network with spatiotemporal chaos behaviors. In this work, the traditional method of sliding mode control is firstly modified for researching conveniently the synchronization tracking of uncertain discrete network. Further, the network sliding mode surface and control input are designed, and their effectiveness are analyzed. At the same time, we also design the adaptive law to identify availably the uncertain configuration coefficient of the network sliding mode surface. Finally, an example about the small-world network is considered to illustrate the application and effectiveness of the proposed scheme.

  1. Generalized Synchronization with Uncertain Parameters of Nonlinear Dynamic System via Adaptive Control

    PubMed Central

    Yang, Cheng-Hsiung; Wu, Cheng-Lin

    2014-01-01

    An adaptive control scheme is developed to study the generalized adaptive chaos synchronization with uncertain chaotic parameters behavior between two identical chaotic dynamic systems. This generalized adaptive chaos synchronization controller is designed based on Lyapunov stability theory and an analytic expression of the adaptive controller with its update laws of uncertain chaotic parameters is shown. The generalized adaptive synchronization with uncertain parameters between two identical new Lorenz-Stenflo systems is taken as three examples to show the effectiveness of the proposed method. The numerical simulations are shown to verify the results. PMID:25295292

  2. Probabilistic Seismic Hazard Assessment from Incomplete and Uncertain Data

    NASA Astrophysics Data System (ADS)

    Smit, Ansie; Kijko, Andrzej

    2016-04-01

    A question that frequently arises with seismic hazard assessment is why are our assessments so poor? Often the answer is that in many cases the standard applied methodologies do not take into account the nature of seismic event catalogs. In reality these catalogues are incomplete with uncertain magnitude estimates and a significant discrepancy between the empirical data and applied occurrence model. Most probabilistic seismic hazard analysis procedures require knowledge of at least three seismic source parameters: the mean seismic activity rate λ, the Gutenberg-Richter b-value, and the area-characteristic (seismogenic source) maximum possible earthquake magnitude Mmax. In almost all currently used seismic hazard assessment procedures utilizing these three parameters, it's explicitly assumed that all three remain constant over a specified time and space. However, closer examination of most earthquake catalogues indicates that there are significant spatial and temporal variations in the seismic activity rate λ as well as the Gutenberg-Richter b-value. In the proposed methodology the maximum likelihood estimation of these earthquake hazard parameters takes into account the incompleteness of catalogues, uncertainty in the earthquake magnitude determination as well as the uncertainty associated with the applied earthquake occurrence models. The uncertainty in the earthquake occurrence models are introduced by assuming that both, the mean, seismic activity rate λ and the b-value of Gutenberg-Richter are random variables, each described by the Gamma distribution. The approach results in the extension of the classic frequency-magnitude Gutenberg-Richter relation and the Poisson distribution of number of earthquakes, with their compounded counterparts. The proposed procedure is applied in the estimation of the seismic parameters for the area of Ceres-Tulbagh, South Africa, which experienced the strongest earthquake in the country's recorded history. In this example it is

  3. Human perception of electric fields and ion currents associated with high-voltage DC transmission lines.

    PubMed

    Blondin, J P; Nguyen, D H; Sbeghen, J; Goulet, D; Cardinal, C; Maruvada, P S; Plante, M; Bailey, W H

    1996-01-01

    The objective of this study was to assess the ability of humans to detect the presence of DC electric field and ion currents. An exposure chamber simulating conditions present in the vicinity of high-voltage DC (HVDC) lines was designed and built for this purpose. In these experiments, the facility was used to expose observers to DC electric fields up to 50 kV/m and ion current densities up to 120 nA/m2. Forty-eight volunteers (25 women and 23 men) between the ages of 18 and 57 years served as observers. Perception of DC fields was examined by using two psychophysical methods: an adaptive staircase procedure and a rating method derived from signal-detection theory. Subjects completed three different series of observations by using each of these methods; one was conducted without ion currents, and the other two involved various combinations of electric fields and ion currents. Overall, subjects were significantly more likely to detect DC fields as the intensity increased. Observers were able to detect the presence of DC fields alone, but only at high intensities; the average threshold was 45 kV/m. Except in the most sensitive individuals, ion current densities up to 60 nA/m2 did not significantly facilitate the detection of DC fields. However, higher ion current densities were associated with a substantial lowering of sensory thresholds in a large majority of observers. Data analysis also revealed large variations in perceptual thresholds among observers. Normative data indicating DC field and ion current intensities that can be detected by 50% of all observers are provided. In addition, for the most sensitive observers, several other detection proportions were derived from the distribution of individual detection capabilities. These data can form the basis for environmental guidelines relating to the design of HVDC lines.

  4. Identification of trans-acting factors regulating SamDC expression in Oryza sativa

    SciTech Connect

    Basu, Supratim; Roychoudhury, Aryadeep; Sengupta, Dibyendu N.

    2014-03-07

    Highlights: • Identification of cis elements responsible for SamDC expression by in silico analysis. • qPCR analysis of SamDC expression to abiotic and biotic stress treatments. • Detection of SamDC regulators using identified cis-elements as probe by EMSA. • Southwestern Blot analysis to predict the size of the trans-acting factors. - Abstract: Abiotic stress affects the growth and productivity of crop plants; to cope with the adverse environmental conditions, plants have developed efficient defense machinery comprising of antioxidants like phenolics and flavonoids, and osmolytes like polyamines. SamDC is a key enzyme in the polyamine biosynthesis pathway in plants. In our present communication we have done in silico analysis of the promoter region of SamDC to look for the presence of different cis-regulatory elements contributing to its expression. Based on the presence of different cis-regulatory elements we completed comparative analysis of SamDC gene expression in rice lamina of IR-29 and Nonabokra by qPCR in response to the abiotic stress treatments of salinity, drought, cold and the biotic stress treatments of ABA and light. Additionally, to explore the role of the cis-regulatory elements in regulating the expression of SamDC gene in plants we comparatively analyzed the binding of rice nuclear proteins prepared from IR-29 and Nonabokra undergoing various stress treatments. The intensity of the complex formed was low and inducible in IR-29 in contrast to Nonabokra. Southwestern blot analysis helped in predicting the size of the trans-acting factors binding to these cis-elements. To our knowledge this is the first report on the comprehensive analysis of SamDC gene expression in rice and identification of the trans-acting factors regulating its expression.

  5. Differential outcome of TRIF-mediated signaling in TLR4 and TLR3 induced DC maturation.

    PubMed

    Hu, Wei; Jain, Aakanksha; Gao, Yajing; Dozmorov, Igor M; Mandraju, Rajakumar; Wakeland, Edward K; Pasare, Chandrashekhar

    2015-11-10

    Recognition of pathogen-associated molecular patterns by Toll-like receptors (TLRs) on dendritic cells (DCs) leads to DC maturation, a process involving up-regulation of MHC and costimulatory molecules and secretion of proinflammatory cytokines. All TLRs except TLR3 achieve these outcomes by using the signaling adaptor myeloid differentiation factor 88. TLR4 and TLR3 can both use the Toll-IL-1 receptor domain-containing adaptor inducing IFN-β (TRIF)-dependent signaling pathway leading to IFN regulatory factor 3 (IRF3) activation and induction of IFN-β and -α4. The TRIF signaling pathway, downstream of both of these TLRs, also leads to DC maturation, and it has been proposed that the type I IFNs act in cis to induce DC maturation and subsequent effects on adaptive immunity. The present study was designed to understand the molecular mechanisms of TRIF-mediated DC maturation. We have discovered that TLR4-TRIF-induced DC maturation was independent of both IRF3 and type I IFNs. In contrast, TLR3-mediated DC maturation was completely dependent on type I IFN feedback. We found that differential activation of mitogen-activated protein kinases by the TLR4- and TLR3-TRIF axes determined the type I IFN dependency for DC maturation. In addition, we found that the adjuvanticity of LPS to induce T-cell activation is completely independent of type I IFNs. The important distinction between the TRIF-mediated signaling pathways of TLR4 and TLR3 discovered here could have a major impact in the design of future adjuvants that target this pathway.

  6. Analysis of high voltage step-up nonisolated DC-DC boost converters

    NASA Astrophysics Data System (ADS)

    Alisson Alencar Freitas, Antônio; Lessa Tofoli, Fernando; Junior, Edilson Mineiro Sá; Daher, Sergio; Antunes, Fernando Luiz Marcelo

    2016-05-01

    A high voltage step-up nonisolated DC-DC converter based on coupled inductors suitable to photovoltaic (PV) systems applications is proposed in this paper. Considering that numerous approaches exist to extend the voltage conversion ratio of DC-DC converters that do not use transformers, a detailed comparison is also presented among the proposed converter and other popular topologies such as the conventional boost converter and the quadratic boost converter. The qualitative analysis of the coupled-inductor-based topology is developed so that a design procedure can be obtained, from which an experimental prototype is implemented to validate the theoretical assumptions.

  7. High power density dc/dc converter: Component selection and design

    NASA Technical Reports Server (NTRS)

    Divan, Deepakraj M.

    1989-01-01

    Further work pertaining to design considerations for the new high power, high frequency dc/dc converters is discussed. The goal of the project is the development of high power, high power density dc/dc converters at power levels in the multi-kilowatt to megawatt range for aerospace applications. The prototype converter is rated for 50 kW at a switching frequency of 50 kHz, with an input voltage of 200 Vdc and an output of 2000 Vdc. The overall power density must be in the vicinity of 0.2 to 0.3 kg/kW.

  8. Egr2 induced during DC development acts as an intrinsic negative regulator of DC immunogenicity.

    PubMed

    Miah, Mohammad Alam; Byeon, Se Eun; Ahmed, Md Selim; Yoon, Cheol-Hee; Ha, Sang-Jun; Bae, Yong-Soo

    2013-09-01

    Early growth response gene 2 (Egr2), which encodes a zinc finger transcription factor, is rapidly and transiently induced in various cell types independently of de novo protein synthesis. Although a role for Egr2 is well established in T-cell development, Egr2 expression and its biological function in dendritic cells (DCs) have not yet been described. Here, we demonstrate Egr2 expression during DC development, and its role in DC-mediated immune responses. Egr2 is expressed in the later stage of DC development from BM precursor cells. Even at steady state, Egr2 is highly expressed in mouse splenic DCs. Egr2-knockdown (Egr2-KD) DCs showed increased levels of major histocompatability complex (MHC) class I and II and co-stimulatory molecules, and enhanced antigen uptake and migratory capacities. Furthermore, Egr2-KD abolished SOCS1 expression and signal transducer and activator of transcription 5 (STAT5) activation during DC development, probably resulting in the enhancement of IL-12 expression and Th1 immunogenicity of a DC vaccine. DC-mediated cytotoxic T lymphocyte (CTL) activation and antitumor immunity were significantly enhanced by Egr2-KD, and impaired by Egr2 overexpression in antigen-pulsed DC vaccines. These data suggest that Egr2 acts as an intrinsic negative regulator of DC immunogenicity and can be an attractive molecular target for DC vaccine development.

  9. Efficiency and Regulation of Commercial Low Power DC/DC Converter Modules at Low Temperatures

    NASA Technical Reports Server (NTRS)

    Elbuluk, Malik E.; Gerber, Scott; Hammoud, Ahmad; Patterson, Richard L.

    2000-01-01

    DC/DC converters that are capable of operating at cryogenic temperatures are anticipated to play an important role in the power systems of future NASA deep space missions. Design of these converters to survive cryogenic temperatures will improve the power system performance, and reduce development and launch costs. At the NASA Glenn Research Center Low Temperature Electronics Laboratory, several commercial off-the-shelf dc/dc converter modules were evaluated for their low temperature performance. Various parameters were investigated as a function of temperature, in the range of 20 C to -190 C. Data pertaining to the efficiency and voltage regulation of the tested converters is presented and discussed.

  10. Interleaved DC-DC Converter with Discrete Duty Cycle and Open Loop Control

    NASA Astrophysics Data System (ADS)

    Kroics, K.; Sokolovs, A.

    2016-08-01

    The authors present the control principle of the multiphase interleaved DC-DC converter that can be used to vastly reduce output current ripple of the converter. The control algorithm can be easily implemented by using microcontroller without current loop in each phase. The converter works in discontinuous conduction mode (DCM) but close to boundary conduction mode (BCM). The DC-DC converter with such a control algorithm is useful in applications that do not require precise current adjustment. The prototype of the converter has been built. The experimental results of the current ripple are presented in the paper.

  11. The application of standardized control and interface circuits to three dc to dc power converters.

    NASA Technical Reports Server (NTRS)

    Yu, Y.; Biess, J. J.; Schoenfeld, A. D.; Lalli, V. R.

    1973-01-01

    Standardized control and interface circuits were applied to the three most commonly used dc to dc converters: the buck-boost converter, the series-switching buck regulator, and the pulse-modulated parallel inverter. The two-loop ASDTIC regulation control concept was implemented by using a common analog control signal processor and a novel digital control signal processor. This resulted in control circuit standardization and superior static and dynamic performance of the three dc-to-dc converters. Power components stress control, through active peak current limiting and recovery of switching losses, was applied to enhance reliability and converter efficiency.

  12. Uncertainity analysis of selected sources of errors in bioelectromagnetic investigations.

    PubMed

    Dlugosz, Tomasz

    2014-01-01

    The aim of this paper is to focus attention of experimenters on several sources of error that are not taken into account in the majority of bioelectromagnetics experiments, and which may lead to complete falsification of the results of the experiments.

  13. ASTER Washington, D.C.

    NASA Technical Reports Server (NTRS)

    2000-01-01

    The White House, the Jefferson Memorial, and the Washington Monument with its shadow are all visible in this image of Washington, D.C. With its 15-meter spatial resolution, ASTER can see individual buildings. Taken on June 1, 2000, this image covers an area 14 kilometers (8.5 miles) wide and 13.7 kilometers (8.2 miles) long in three bands of the reflected visible and infrared wavelength region. The combination of visible and near infrared bands displays vegetation in red and water in dark grays. The Potomac River flows from the middle left to the bottom center. The large red area west of the river is Arlington National Cemetery.

    Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of International Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products. Dr. Anne Kahle at NASA's Jet Propulsion Laboratory, Pasadena, California, is the U.S. science team leader; Moshe Pniel of JPL is the project manager. ASTER is the only high-resolution imaging sensor on Terra. The primary goal of the ASTER mission is to obtain high-resolution image data in 14 channels over the entire land surface, as well as black and white stereo images. With revisit time of between 4 and 16 days, ASTER will provide the capability for repeat coverage of changing areas on Earth's surface.

    The broad spectral coverage and high spectral resolution of ASTER will provide scientists in numerous disciplines with critical information for surface mapping and monitoring dynamic conditions and temporal change. Examples of applications include monitoring glacial advances and retreats, potentially active volcanoes, thermal pollution, and coral reef degradation; identifying crop stress; determining cloud morphology and physical properties; evaluating wetlands

  14. Robust stabilization, robust performance, and disturbance attenuation for uncertain linear systems

    NASA Technical Reports Server (NTRS)

    Wang, Yeih J.; Shieh, Leang S.; Sunkel, John W.

    1992-01-01

    This paper presents a linear quadratic regulator approach to the robust stabilization, robust performance, and disturbance attenuation of uncertain linear systems. The state-feedback designed systems provide both the robust stability with optimal performance and the disturbance attenuation with H-infinity-norm bounds. The proposed approach can be applied to matched and/or mismatched uncertain linear systems. For a matched uncertain linear system, it is shown that the disturbance attenuation robust-stabilizing controllers with or without optimal performance always exist and can be easily determined without searching; whereas, for a mismatched uncertain linear system, the introduced tuning parameters greatly enhance the flexibility of finding the disturbance-attenuation robust-stabilizing controllers.

  15. Positive affect increases secondary control among causally uncertain individuals.

    PubMed

    Tobin, Stephanie J; George, Melanie P

    2015-01-01

    Secondary control (acceptance of and adjustment to negative events) is thought to promote positive affect. We examined the opposite path: could positive affect increase secondary control, particularly among individuals high in causal uncertainty, who stand to benefit from it the most? In two studies, participants completed a causal uncertainty scale, thought about a problem while listening to affect-inducing music or no music, and then completed items that assessed secondary control. In Study 1, the music induced positive or negative affect. In Study 2, the music induced affect that was high or low in activation and positive or negative in valence. In both studies, we found that positive affect-inducing music increased secondary control among high causal uncertainty participants. Furthermore, trait affect did not account for the effects of causal uncertainty, and music did not influence primary control. These findings show that secondary control can fluctuate as a function of state affect.

  16. The Experience of Strategic Thinking in a Volatile, Complex, Uncertain & Ambiguous (VUCA) Environment

    DTIC Science & Technology

    2014-08-01

    Dale L. Moore, Aug., 2014 The Experience of Strategic Thinking in a Volatile, Complex, Uncertain & Ambiguous (VUCA) Environment Dr. Dale L...TITLE AND SUBTITLE The Experience of Strategic Thinking in a Volatile, Complex, Uncertain & Ambiguous (VUCA) Environment 5a. CONTRACT NUMBER 5b...Title: The Experience of Strategic Thinking in VUCA Environments Purpose of the Study: To understand the experience of leaders when they think

  17. An Uncertain Deterrence: Bernard Brodie, Indian Nuclear Strategy, and the Problems of Stability

    DTIC Science & Technology

    1997-01-01

    NATIONAL DEFENSE UNNERSm NATIONAL WAR COLLEGE An Uncertain Deterrence : Bernard Brodie, Indian Nuclear Strategy, and the Problem of Stability...COVERED 00-00-1997 to 00-00-1997 4. TITLE AND SUBTITLE An Uncertain Deterrence: Bernard Brodie, Indian Nuclear Strategy, and the Problems of...themselves anconsciously reject tie concept of deterrence based on retalirrtron’. The above statement was excerpted from Bernard Brodie’s 1959 sruc?y

  18. Homogeneous piecewise polynomial Lyapunov function for robust stability of uncertain piecewise linear system

    SciTech Connect

    BenAbdallah, Abdallah; Hammami, Mohamed Ali; Kallel, Jalel

    2009-03-05

    In this paper we present some sufficient conditions for the robust stability and stabilization of time invariant uncertain piecewise linear system using homogenous piecewise polynomial Lyapunov function. The proposed conditions are given in terms of linear matrix inequalities which can be numerically solved. An application of the obtained result is given. It consists in resolving the stabilization of piecewise uncertain linear control systems by using a state piecewise linear feedback.

  19. Buckling of structures with uncertain imperfections - Personal perspective

    NASA Technical Reports Server (NTRS)

    Elishakoff, Isaac

    1998-01-01

    The previous review on stochastic buckling of structures was written by Amazigo in 1976. This review summarizes some of the developments which took place in recent two decades. A brief overview is given of the effect on uncertainty in the initial geometric imperfections, elastic moduli, applied forces, and thickness variation. For the benefit of the thinking reader, the review has a critical nature. It should be noted that this manuscript has yet to be completed.

  20. Internet Management: Limited Progress on Privatization Project Makes Outcome Uncertain

    DTIC Science & Technology

    2007-11-02

    and Numbers ( ICANN ), a not-for-profit corporation, to carry out the transition. In November 1998, the Department entered into an agreement with ICANN ...these assurances, the Department and ICANN agreed in the MOU to complete a set of transition tasks. The Department’s tasks mainly relate to providing...advice, coordination with foreign governments, and general oversight of the transition. ICANN agreed to undertake tasks that call for it to design

  1. Robust nonlinear generalised predictive control for a class of uncertain nonlinear systems via an integral sliding mode approach

    NASA Astrophysics Data System (ADS)

    Errouissi, Rachid; Yang, Jun; Chen, Wen-Hua; Al-Durra, Ahmed

    2016-08-01

    In this paper, a robust nonlinear generalised predictive control (GPC) method is proposed by combining an integral sliding mode approach. The composite controller can guarantee zero steady-state error for a class of uncertain nonlinear systems in the presence of both matched and unmatched disturbances. Indeed, it is well known that the traditional GPC based on Taylor series expansion cannot completely reject unknown disturbance and achieve offset-free tracking performance. To deal with this problem, the existing approaches are enhanced by avoiding the use of the disturbance observer and modifying the gain function of the nonlinear integral sliding surface. This modified strategy appears to be more capable of achieving both the disturbance rejection and the nominal prescribed specifications for matched disturbance. Simulation results demonstrate the effectiveness of the proposed approach.

  2. 75 FR 65651 - In the Matter of Certain DC-DC Controllers and Products Containing Same; Notice of Commission...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-26

    ... COMMISSION In the Matter of Certain DC-DC Controllers and Products Containing Same; Notice of Commission..., DC 20436, telephone (202) 708-2532. Copies of non- confidential documents filed in connection with...., Washington, DC 20436, telephone (202) 205-2000. General information concerning the Commission may also...

  3. 75 FR 17433 - In the Matter of Certain DC-DC Controllers and Products Containing Same; Notice of Commission...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-06

    ... COMMISSION In the Matter of Certain DC-DC Controllers and Products Containing Same; Notice of Commission... Street, SW., Washington, DC 20436, telephone (202) 708-2532. Copies of non- confidential documents filed..., 500 E Street, SW., Washington, DC 20436, telephone (202) 205-2000. General information concerning...

  4. 76 FR 55109 - In the Matter of Certain DC-DC Controllers and Products Containing Same; Notice of Institution of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-06

    ... COMMISSION In the Matter of Certain DC-DC Controllers and Products Containing Same; Notice of Institution of... Trade Commission, 500 E Street, SW., Washington, DC 20436, telephone (202) 205-3061. Copies of all.... International Trade Commission, 500 E Street, SW., Washington, DC 20436, telephone 202-205-2000....

  5. 75 FR 28283 - In the Matter of: Certain DC-DC Controllers and Products Containing Same; Notice of Commission...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-20

    ... COMMISSION In the Matter of: Certain DC-DC Controllers and Products Containing Same; Notice of Commission..., 500 E Street, SW., Washington, DC 20436, telephone (202) 708-2532. Copies of non- confidential... Commission, 500 E Street, SW., Washington, DC 20436, telephone (202) 205-2000. General information...

  6. 75 FR 65655 - In the Matter of Certain DC-DC Controllers and Products Containing Same; Notice of Commission...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-26

    ... COMMISSION In the Matter of Certain DC-DC Controllers and Products Containing Same; Notice of Commission..., DC 20436, telephone (202) 708-2532. Copies of non- confidential documents filed in connection with...., Washington, DC 20436, telephone (202) 205-2000. General information concerning the Commission may also...

  7. Single Event Burnout in DC-DC Converters for the LHC Experiments

    SciTech Connect

    Claudio H. Rivetta et al.

    2001-09-24

    High voltage transistors in DC-DC converters are prone to catastrophic Single Event Burnout in the LHC radiation environment. This paper presents a systematic methodology to analyze single event effects sensitivity in converters and proposes solutions based on de-rating input voltage and output current or voltage.

  8. Regulation of a lightweight high efficiency capacitator diode voltage multiplier dc-dc converter

    NASA Technical Reports Server (NTRS)

    Harrigill, W. T., Jr.; Myers, I. T.

    1976-01-01

    A method for the regulation of a capacitor diode voltage multiplier dc-dc converter has been developed which has only minor penalties in weight and efficiency. An auxiliary inductor is used, which only handles a fraction of the total power, to control the output voltage through a pulse width modulation method in a buck boost circuit.

  9. Regulation of a lightweight high efficiency capacitor diode voltage multiplier dc-dc converter

    NASA Technical Reports Server (NTRS)

    Harrigill, W. T., Jr.; Myers, I. T.

    1976-01-01

    A method for the regulation of a capacitor diode voltage multiplier dc-dc converter has been developed which has only minor penalties in weight and efficiency. An auxiliary inductor is used, which only handles a fraction of the total power, to control the output voltage through a pulse width modulation method in a buck boost circuit.

  10. Low noise DC to DC converters for the sLHC experiments

    NASA Astrophysics Data System (ADS)

    Allongue, B.; Blanchot, G.; Faccio, F.; Fuentes, C.; Michelis, S.; Orlandi, S.

    2010-11-01

    The development of front-end systems for the ATLAS tracker at the sLHC is now in progress and the availability of radiation tolerant buck converter ASICs enables the implementation of DC to DC converter based powering schemes. The front-end systems powered in this manner will be exposed to the radiated and conducted noise emitted by the converters. The electromagnetic compatibility between DC to DC converters and ATLAS short strip tracker hybrid prototypes has been studied with specific susceptibility tests. Different DC to DC converter prototypes have been designed following a noise optimization methodology to match the noise requirements of these front-end systems. The DC to DC converter developed in this manner presents a negligible emission of noise that was confirmed by system tests on an ATLAS tracker front-end module prototype. As a result of this, power converters can now be integrated in close vicinity of front-end chips without compromising their overall noise performance.

  11. Modelling, Simulation and Construction of a DC/DC Boost Power Converter: A School Experimental System

    ERIC Educational Resources Information Center

    Silva-Ortigoza, R.; Silva-Ortigoza, G.; Hernandez-Guzman, V. M.; Saldana-Gonzalez, G.; Marcelino-Aranda, M.; Marciano-Melchor, M.

    2012-01-01

    We introduce a dc/dc boost power converter as a didactic prototype intended to support courses on electric circuit analysis experimentally. The corresponding mathematical model is obtained, the converter is designed and an experimental setup is described, constructed and tested. Simplicity of construction as well as low cost of components renders…

  12. Beyond FASFA Completion

    ERIC Educational Resources Information Center

    Castleman, Ben; Page, Lindsay

    2015-01-01

    The Free Application for Federal Student Aid (FAFSA)--which students must complete to qualify for most federal, state, and institutional financial aid--is a gateway to college through which many students must pass, particularly those from low- to moderate-income households (King, 2004; Kofoed, 2013). Yet given the complexity of the…

  13. Making College Completion Personal

    ERIC Educational Resources Information Center

    Thomas, Heather

    2011-01-01

    There are countless justifications for why young adults, faced with so many distractions, do not complete their educations. Many students fail to finish college because of a lack of information and understanding about healthy relationships and sex education. The author's own struggles and eventual successes as a student and mother compelled her to…

  14. College Completion Tool Kit

    ERIC Educational Resources Information Center

    US Department of Education, 2011

    2011-01-01

    In March, 2009, President Obama proposed the American Graduation Initiative, which established the goal that by 2020 the United States will regain its position as the nation with the highest percentage of its population holding post-secondary degrees and credentials. The College Completion Toolkit provides information that governors and other…

  15. Completing a Simple Circuit.

    ERIC Educational Resources Information Center

    Slater, Timothy F.; Adams, Jeffrey P.; Brown, Thomas R.

    2000-01-01

    Students have problems successfully arranging an electric circuit to make the bulb produce light. Investigates the percentage of students able to complete a circuit with a given apparatus, and the effects of prior experience on student success. Recommends hands-on activities at the elementary and secondary school levels. (Contains 14 references.)…

  16. Improved DC Gun Insulator Assembly

    SciTech Connect

    Sah, R.; Dudas, A.; Neubauer, M. L.; Poelker, M.; Surles-Law, K. E.L.

    2010-05-23

    Many user fa­cil­i­ties such as syn­chrotron ra­di­a­tion light sources and free elec­tron lasers re­quire ac­cel­er­at­ing struc­tures that sup­port elec­tric fields of 10-100 MV/m, es­pe­cial­ly at the start of the ac­cel­er­a­tor chain where ce­ram­ic in­su­la­tors are used for very high gra­di­ent DC guns. These in­su­la­tors are dif­fi­cult to man­u­fac­ture, re­quire long com­mis­sion­ing times, and often ex­hib­it poor re­li­a­bil­i­ty. Two tech­ni­cal ap­proach­es to solv­ing this prob­lem will be in­ves­ti­gat­ed. First­ly, in­vert­ed ce­ram­ics offer so­lu­tions for re­duced gra­di­ents be­tween the elec­trodes and ground. An in­vert­ed de­sign will be pre­sent­ed for 350 kV, with max­i­mum gra­di­ents in the range of 5-10 MV/m. Sec­ond­ly, novel ce­ram­ic man­u­fac­tur­ing pro­cess­es will be stud­ied, in order to pro­tect triple junc­tion lo­ca­tions from emis­sion, by ap­ply­ing a coat­ing with a bulk re­sis­tiv­i­ty. The pro­cess­es for cre­at­ing this coat­ing will be op­ti­mized to pro­vide pro­tec­tion as well as be used to coat a ce­ram­ic with an ap­pro­pri­ate gra­di­ent in bulk re­sis­tiv­i­ty from the vac­u­um side to the air side of an HV stand­off ce­ram­ic cylin­der. Ex­am­ple in­su­la­tor de­signs are being com­put­er mod­elled, and in­su­la­tor sam­ples are being man­u­fac­tured and test­ed

  17. Pulsed dc self-sustained magnetron sputtering

    SciTech Connect

    Wiatrowski, A.; Posadowski, W. M.; Radzimski, Z. J.

    2008-09-15

    The magnetron sputtering has become one of the commonly used techniques for industrial deposition of thin films and coatings due to its simplicity and reliability. At standard magnetron sputtering conditions (argon pressure of {approx}0.5 Pa) inert gas particles (necessary to sustain discharge) are often entrapped in the deposited films. Inert gas contamination can be eliminated during the self-sustained magnetron sputtering (SSS) process, where the presence of the inert gas is not a necessary requirement. Moreover the SSS process that is possible due to the high degree of ionization of the sputtered material also gives a unique condition during the transport of sputtered particles to the substrate. So far it has been shown that the self-sustained mode of magnetron operation can be obtained using dc powering (dc-SSS) only. The main disadvantage of the dc-SSS process is its instability related to random arc formation. In such case the discharge has to be temporarily extinguished to prevent damaging both the magnetron source and power supply. The authors postulate that pulsed powering could protect the SSS process against arcs, similarly to reactive pulsed magnetron deposition processes of insulating thin films. To put this concept into practice, (i) the high enough plasma density has to be achieved and (ii) the type of pulsed powering has to be chosen taking plasma dynamics into account. In this article results of pulsed dc self-sustained magnetron sputtering (pulsed dc-SSS) are presented. The planar magnetron equipped with a 50 mm diameter and 6 mm thick copper target was used during the experiments. The maximum target power was about 11 kW, which corresponded to the target power density of {approx}560 W/cm{sup 2}. The magnetron operation was investigated as a function of pulse frequency (20-100 kHz) and pulse duty factor (50%-90%). The discharge (argon) extinction pressure level was determined for these conditions. The plasma emission spectra (400-410 nm range

  18. Homopolar dc motor and trapped flux brushless dc motor using high temperature superconductor materials

    SciTech Connect

    Crapo, A.D.; Lloyd, J.D. )

    1991-03-01

    This paper reports on two motors designed and built for use with high temperature superconductor (HTSC) materials. They are a homopolar DC motor that will use HTSC field windings and a brushless DC motor that will use bulk HTSC material to trap flux in steel rotor poles. The HTSC field windings of the homopolar DC motor are designed to operate at 1000 Amperes/cm{sup 2} in a 0.010 Tesla (100 Gauss) field. In order to maximize torque in the homopolar DC motor, an iron magnetic circuit with small air gaps gives maximum flux for minimum Ampere turns in the field. A copper field winding version of the homopolar DC motor has been tested while the authors wait for 575 Ampere turn HTSC coils.

  19. Complete Genome of Stachybotrys chartarum strain 51-11

    EPA Pesticide Factsheets

    Complete genome sequence of the fungus Stachybotrys chartarum. Sequences can be used to identify genes, genetic pathways, gene clusters, genetic organization, etc. utilizing appropriate bioinformatics software.This dataset is associated with the following publication:Betancourt , D., T. Dean , J. Kim, and J. Levy. Genome sequence of Stachybotrys chartarum Strain 51-11. Genome Announcements. American Society for Microbiology, Washington, DC, USA, 3(6): 1114-1115, (2015).

  20. Nuclear Forensics Analysis with Missing and Uncertain Data

    SciTech Connect

    Langan, Roisin T.; Archibald, Richard K.; Lamberti, Vincent

    2015-10-05

    We have applied a new imputation-based method for analyzing incomplete data, called Monte Carlo Bayesian Database Generation (MCBDG), to the Spent Fuel Isotopic Composition (SFCOMPO) database. About 60% of the entries are absent for SFCOMPO. The method estimates missing values of a property from a probability distribution created from the existing data for the property, and then generates multiple instances of the completed database for training a machine learning algorithm. Uncertainty in the data is represented by an empirical or an assumed error distribution. The method makes few assumptions about the underlying data, and compares favorably against results obtained by replacing missing information with constant values.

  1. Scheduling in the Face of Uncertain Resource Consumption and Utility

    NASA Technical Reports Server (NTRS)

    Koga, Dennis (Technical Monitor); Frank, Jeremy; Dearden, Richard

    2003-01-01

    We discuss the problem of scheduling tasks that consume a resource with known capacity and where the tasks have varying utility. We consider problems in which the resource consumption and utility of each activity is described by probability distributions. In these circumstances, we would like to find schedules that exceed a lower bound on the expected utility when executed. We first show that while some of these problems are NP-complete, others are only NP-Hard. We then describe various heuristic search algorithms to solve these problems and their drawbacks. Finally, we present empirical results that characterize the behavior of these heuristics over a variety of problem classes.

  2. Ramp technique for dc partial discharge testing

    NASA Astrophysics Data System (ADS)

    Bever, R. S.

    1985-02-01

    The partial discharge (PD) data presently obtained by means of a stepwise ramp technique, for the cases of high voltage (HV) components and such resin-packaged HV devices as the Space Telescope's Faint Object Camera, is acquired separately on part-way ramps to rated voltage and on the intermediate voltage plateaus. For test specimens intended for dc service, this ramp method yields more data on insulation integrity than quiescent dc measurements, especially in the case of specimens of high resistivity which causes the discharge frequency to be deceptively low at constant dc voltage. During upward ramping the voltage distribution is capacitive, and the PD behavior resembles that of an ac test. Many more pulses are obtained in the voids without the heat otherwise generated by the application of 60-Hz ac. PD histograms are presented for various materials, with and without intentional defects.

  3. New Experimental Data in DC745U

    SciTech Connect

    Ortiz-Acosta, Denisse; Cady, Carl; Densmore, Crystal

    2012-06-18

    The objectives of this project are: (1) study the molecular and mechanical properties of DC745U - (a) DC745U is a silicone elastomer used in several weapons systems, (b) depending on their chemistry and formulation, polymers can be susceptible to damage and failures due to weak chemical linkages and physical interactions, (c) inefficient production processes can generate heterogeneities throughout the material that can contribute negatively to the overall performance and lifetime of the polyer, (d) aging, long-term thermal and radioactive conditions, and mechanical strains can affect the materials network structure and contribute to the degradation of the production; (2) characterization of DC745U materials cured under different conditions to determine possible differences to the polymer structure; and (3) this work is relevant to mission-critical programs and for supporting programmatic work for weapon research.

  4. Image Zoom Completion.

    PubMed

    Hidane, Moncef; El Gheche, Mireille; Aujol, Jean-Francois; Berthoumieu, Yannick; Deledalle, Charles-Alban

    2016-08-01

    We consider the problem of recovering a high-resolution image from a pair consisting of a complete low-resolution image and a high-resolution but incomplete one. We refer to this task as the image zoom completion problem. After discussing possible contexts in which this setting may arise, we introduce a nonlocal regularization strategy, giving full details concerning the numerical optimization of the corresponding energy and discussing its benefits and shortcomings. We also derive two total variation-based algorithms and evaluate the performance of the proposed methods on a set of natural and textured images. We compare the results and get with those obtained with two recent state-of-the-art single-image super-resolution algorithms.

  5. SRS SWPF Construction Completion

    SciTech Connect

    Craig, Jack; Sheppard, Frank; Marks, Pam

    2016-08-04

    Now that construction is complete, DOE and construction contractor Parsons, are focusing on testing the Savannah River Site’s Salt Waste Processing Facility (SWPF) systems and training the workforce to operate the plant in preparation for the start of operations. Once in operation, the SWPF will significantly increase processing rates at SRS tank farms in an effort to empty the site’s high-level radioactive waste tanks.

  6. SRS SWPF Construction Completion

    ScienceCinema

    Craig, Jack; Sheppard, Frank; Marks, Pam

    2016-08-17

    Now that construction is complete, DOE and construction contractor Parsons, are focusing on testing the Savannah River Site’s Salt Waste Processing Facility (SWPF) systems and training the workforce to operate the plant in preparation for the start of operations. Once in operation, the SWPF will significantly increase processing rates at SRS tank farms in an effort to empty the site’s high-level radioactive waste tanks.

  7. Three phase full wave dc motor decoder

    NASA Technical Reports Server (NTRS)

    Studer, P. A. (Inventor)

    1977-01-01

    A three phase decoder for dc motors is disclosed which employs an extremely simple six transistor circuit to derive six properly phased output signals for fullwave operation of dc motors. Six decoding transistors are coupled at their base-emitter junctions across a resistor network arranged in a delta configuration. Each point of the delta configuration is coupled to one of three position sensors which sense the rotational position of the motor. A second embodiment of the invention is disclosed in which photo-optical isolators are used in place of the decoding transistors.

  8. DC Characterization of the Coaxial Superconducting Cable

    NASA Astrophysics Data System (ADS)

    Šouc, J.; Gömöry, F.; Vojenčiak, M.; Frolek, L.; Isfort, D.; Ehrenberg, J.; Bock, J.

    2008-01-01

    Coaxial cable model with superconducting core and superconducting shield conductor was constructed and tested in DC regime. While the core was already examined in our previous works, in this contribution the detailed study of the superconducting shield conductor in DC conditions is presented. It consists of 16 ReBCO coated tapes with critical current 35 A each connected in parallel. Using shunts with known values placed in series the currents in individual tapes were possible to measure. Distribution of the total cable current into the individual tapes was monitored and its influence on critical current of the cable is discussed.

  9. "DC:0-3" to "DC:0-3R" to "DC:0-5": A New Edition

    ERIC Educational Resources Information Center

    Zeanah, Charles H., Jr.; Carter, Alice; Cohen, Julie; Egger, Helen; Keren, Miri; Gleason, Mary Margaret; Lieberman, Alicia F.; Mulrooney, Kathleen; Oser, Cindy

    2015-01-01

    Originally published in 1994 by ZERO TO THREE as the "Diagnostic Classification of Mental Health and Developmental Disorders of Infancy and Early Childhood" ("DC:0-3") and revised in 2005 by ZERO TO THREE as the "Diagnostic Classification of Mental Health and Developmental Disorders of Infancy and Early Childhood, Revised…

  10. Homopolar dc motor and trapped flux brushless dc motor using high temperature superconductor materials

    NASA Astrophysics Data System (ADS)

    Crapo, Alan D.; Lloyd, Jerry D.

    1991-03-01

    Two motors have been designed and built for use with high-temperature superconductor (HTSC) materials. They are a homopolar dc motor that uses HTSC field windings and a brushless dc motor that uses bulk HTSC materials to trap flux in steel rotor poles. The HTSC field windings of the homopolar dc motor are designed to operate at 1000 A/sq cm in a 0.010-T field. In order to maximize torque in the homopolar dc motor, an iron magnetic circuit with small air gaps gives maximum flux for minimum Ampere turns in the field. A copper field winding version of the homopolar dc motor has been tested while waiting for 575 A turn HTSC coils. The trapped flux brushless dc motor has been built and is ready to test melt textured bulk HTSC rings that are currently being prepared. The stator of the trapped flux motor will impress a magnetic field in the steel rotor poles with warm HTSC bulk rings. The rings are then cooled to 77 K to trap the flux in the rotor. The motor can then operate as a brushless dc motor.

  11. Nuclear Forensics Analysis with Missing and Uncertain Data

    DOE PAGES

    Langan, Roisin T.; Archibald, Richard K.; Lamberti, Vincent

    2015-10-05

    We have applied a new imputation-based method for analyzing incomplete data, called Monte Carlo Bayesian Database Generation (MCBDG), to the Spent Fuel Isotopic Composition (SFCOMPO) database. About 60% of the entries are absent for SFCOMPO. The method estimates missing values of a property from a probability distribution created from the existing data for the property, and then generates multiple instances of the completed database for training a machine learning algorithm. Uncertainty in the data is represented by an empirical or an assumed error distribution. The method makes few assumptions about the underlying data, and compares favorably against results obtained bymore » replacing missing information with constant values.« less

  12. 75 FR 6162 - Airworthiness Directives; McDonnell Douglas Corporation Model DC-9-81 (MD-81), DC-9-82 (MD-82...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-08

    ... Corporation Model DC- 9-81 (MD-81), DC-9-82 (MD-82), DC-9-83 (MD-83), DC-9-87 (MD-87), and MD-88 Airplanes... Model DC-9-81 (MD-81), DC-9-82 (MD-82), DC-9-83 (MD-83), DC-9-87 (MD-87), and MD-88 airplanes. This... material fatigue from normal flap operating loads. We are proposing this AD to detect and correct...

  13. 75 FR 34661 - Airworthiness Directives; McDonnell Douglas Corporation Model DC-9-81 (MD-81), DC-9-82 (MD-82...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-18

    ... Corporation Model DC- 9-81 (MD-81), DC-9-82 (MD-82), DC-9-83 (MD-83), DC-9-87 (MD-87), and MD-88 Airplanes...: We propose to adopt a new airworthiness directive (AD) for certain Model DC-9-81 (MD-81), DC-9-82 (MD-82), DC-9-83 (MD-83), DC-9- 87 (MD-87), and MD-88 airplanes. This proposed AD would...

  14. 75 FR 47199 - Airworthiness Directives; McDonnell Douglas Corporation Model DC-9-10 Series Airplanes, DC-9-30...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-05

    ... Douglas Corporation Model DC- 9-10 Series Airplanes, DC-9-30 Series Airplanes, DC-9-81 (MD-81) Airplanes, DC-9-82 (MD-82) Airplanes, DC-9-83 (MD-83) Airplanes, DC-9- 87 (MD-87) Airplanes, MD-88 Airplanes... directive (AD), which applies to all McDonnell Douglas Model DC-9-10 series airplanes, DC-9-30...

  15. 75 FR 80744 - Airworthiness Directives; McDonnell Douglas Corporation Model DC-9-81 (MD-81), DC-9-82 (MD-82...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-23

    ... Corporation Model DC- 9-81 (MD-81), DC-9-82 (MD-82), DC-9-83 (MD-83), DC-9-87 (MD-87), and MD-88 Airplanes...: We propose to adopt a new airworthiness directive (AD) for all Model DC-9-81 (MD-81), DC-9-82 (MD-82), DC-9-83 (MD-83), DC-9-87 (MD- 87) and MD-88 airplanes. This proposed AD would require...

  16. New Approaches for DC Balanced SpaceWire

    NASA Technical Reports Server (NTRS)

    Kisin, Alex; Rakow, Glenn

    2016-01-01

    Direct Current (DC) line balanced SpaceWire is attractive for a number of reasons. Firstly, a DC line balanced interface provides the ability to isolate the physical layer with either a transformer or capacitor to achieve higher common mode voltage rejection and/or the complete galvanic isolation in the case of a transformer. Secondly, it provides the possibility to reduce the number of conductors and transceivers in the classical SpaceWire interface by half by eliminating the Strobe line. Depending on the modulator scheme - the clock data recovery frequency requirements may be only twice that of the transmit clock, or even match the transmit clock: depending on the Field Programmable Gate Array (FPGA) decoder design. In this paper, several different implementation scenarios will be discussed. Two of these scenarios are backward compatible with the existing SpaceWire hardware standards except for changes at the character level. Three other scenarios, while decreasing by half the standard SpaceWire hardware components, will require changes at both the character and signal levels and work with fixed rates. Other scenarios with variable data rates will require an additional SpaceWire interface handshake initialization sequence.

  17. New Approaches for Direct Current (DC) Balanced SpaceWire

    NASA Technical Reports Server (NTRS)

    Kisin, Alex; Rakow, Glenn

    2016-01-01

    Direct Current (DC) line balanced SpaceWire is attractive for a number of reasons. Firstly, a DC line balanced interface provides the ability to isolate the physical layer with either a transformer or capacitor to achieve higher common mode voltage rejection and or the complete galvanic isolation in the case of a transformer. And secondly, it provides the possibility to reduce the number of conductors and transceivers in the classical SpaceWire interface by half by eliminating the Strobe line. Depending on the modulator scheme the clock data recovery frequency requirements may be only twice that of the transmit clock, or even match the transmit clock: depending on the Field Programmable Gate Array (FPGA) decoder design. In this paper, several different implementation scenarios will be discussed. Two of these scenarios are backward compatible with the existing SpaceWire hardware standards except for changes at the character level. Three other scenarios, while decreasing by half the standard SpaceWire hardware components, will require changes at both the character and signal levels and work with fixed rates. Other scenarios with variable data rates will require an additional SpaceWire interface handshake initialization sequence.

  18. Comparison of solar panel cooling system by using dc brushless fan and dc water

    NASA Astrophysics Data System (ADS)

    Irwan, Y. M.; Leow, W. Z.; Irwanto, M.; M, Fareq; Hassan, S. I. S.; Safwati, I.; Amelia, A. R.

    2015-06-01

    The purpose of this article is to discuss comparison of solar panel cooling system by using DC brushless fan and DC water pump. Solar photovoltaic (PV) power generation is an interesting technique to reduce non-renewable energy consumption and as a renewable energy. The temperature of PV modules increases when it absorbs solar radiation, causing a decrease in efficiency. A solar cooling system is design, construct and experimentally researched within this work. To make an effort to cool the PV module, Direct Current (DC) brushless fan and DC water pump with inlet/outlet manifold are designed for constant air movement and water flow circulation at the back side and front side of PV module representatively. Temperature sensors were installed on the PV module to detect temperature of PV. PIC microcontroller was used to control the DC brushless fan and water pump for switch ON or OFF depend on the temperature of PV module automatically. The performance with and without cooling system are shown in this experiment. The PV module with DC water pump cooling system increase 3.52%, 36.27%, 38.98%in term of output voltage, output current, output power respectively. It decrease 6.36 °C compare than to PV module without DC water pump cooling system. While DC brushless fan cooling system increase 3.47%, 29.55%, 32.23%in term of output voltage, output current, and output power respectively. It decrease 6.1 °C compare than to PV module without DC brushless fan cooling system. The efficiency of PV module with cooling system was increasing compared to PV module without cooling system; this is because the ambient temperature dropped significantly. The higher efficiency of PV cell, the payback period of the system can be shorted and the lifespan of PV module can also be longer.

  19. Complete thoracic ectopia cordis.

    PubMed

    Alphonso, N; Venugopal, P S; Deshpande, R; Anderson, D

    2003-03-01

    Thoracic ectopia cordis is a rare congenital defect with very few reported survivors after surgical correction. We report a case of complete thoracic ectopia cordis with double outlet right ventricle. The diagnosis was established antenatally and a repair was undertaken soon after birth. The child remained stable and was extubated on the fifth post-operative day. Forty-eight hours later the child succumbed to an unexplained respiratory arrest. Also presented is a review of the different surgical strategies for this unusual condition.

  20. Complete Androgen Insensitivity Syndrome.

    PubMed

    Hashmi, Asra; Hanif, Farha; Hanif, Shumaila Muhammad; Abdullah, Farhan Essa; Shamim, Muhammad Shahid

    2008-07-01

    The incidence of Complete Androgen Insensitivity Syndrome (CAIS) is about 1 in 20,000. People with CAIS are normal appearing females, despite the presence of testes and a 46, XY chromosome constitution. We came across a case in which a 17 years old girl presented with the complaint of inguinal hernia and amenorrhea. Subsequent investigations were done revealing absence of female internal genitalia and the presence of abdominal mass, possibly testes. Syndrome has been linked to mutations in AR, the gene for the human Androgen Receptor, located at Xq11-12 leading to the insensitivity of the receptor to testosterone. Gonadectomy was performed and life long Hormone replacement therapy was advised.

  1. Comparative Study of DC and AC Microgrids in Commercial Buildings Across Different Climates and Operating Profiles: Preprint

    SciTech Connect

    Fregosi, D.; Ravula, S.; Brhlik, D.; Saussele, J.; Frank, S.; Bonnema, E.; Scheib, J.; Wilson, E.

    2015-04-22

    Bosch has developed and demonstrated a novel DC microgrid system designed to maximize utilization efficiency for locally generated photovoltaic energy while offering high reliability, safety, redundancy, and reduced cost compared to equivalent AC systems. Several demonstration projects validating the system feasibility and expected efficiency gains have been completed and additional ones are in progress. This work gives an overview of the Bosch DC microgrid system and presents key results from a large simulation study done to estimate the energy savings of the Bosch DC microgrid over conventional AC systems. The study examined the system performance in locations across the United States for several commercial building types and operating profiles and found that the Bosch DC microgrid uses generated PV energy 6%–8% more efficiently than traditional AC systems.

  2. Insert tree completion system

    SciTech Connect

    Brands, K.W.; Ball, I.G.; Cegielski, E.J.; Gresham, J.S.; Saunders, D.N.

    1982-09-01

    This paper outlines the overall project for development and installation of a low-profile, caisson-installed subsea Christmas tree. After various design studies and laboratory and field tests of key components, a system for installation inside a 30-in. conductor was ordered in July 1978 from Cameron Iron Works Inc. The system is designed to have all critical-pressure-containing components below the mudline and, with the reduced profile (height) above seabed, provides for improved safety of satellite underwater wells from damage by anchors, trawl boards, and even icebergs. In addition to the innovative nature of the tree design, the completion includes improved 3 1/2-in. through flowline (TFL) pumpdown completion equipment with deep set safety valves and a dual detachable packer head for simplified workover capability. The all-hydraulic control system incorporates a new design of sequencing valve for both Christmas tree control and remote flowline connection. A semisubmersible drilling rig was used to initiate the first end flowline connection at the wellhead for subsequent tie-in to the prelaid, surface-towed, all-welded subsea pipeline bundle.

  3. New Logic Circuit with DC Parametric Excitation

    NASA Astrophysics Data System (ADS)

    Sugahara, Masanori; Kaneda, Hisayoshi

    1982-12-01

    It is shown that dc parametric excitation is possible in a circuit named JUDO, which is composed of two resistively-connected Josephson junctions. Simulation study proves that the circuit has large gain and properties suitable for the construction of small, high-speed logic circuits.

  4. A passive DC current sensing methodology

    NASA Astrophysics Data System (ADS)

    Wang, Dong F.; Liu, Huan; Li, Xiaodong; Li, Yang; Xian, Weikang

    2016-10-01

    This paper proposes a method for passive sensing a two-wire DC current without using any cord separator. In this method, a piezoelectric thin-film cantilever with a micro-magnet on its end is positioned near a power cord. The DC current in the power cord induces a magnetic field, which generates a magnetic force acting on the micro-magnet. Consequently, the piezoelectric cantilever is bent and induces an output voltage that is sensitive to small variations of DC currents. A prototype device has been fabricated and experimentally studied. It was found that the initial peak amplitude of the piezoelectric output voltage increases linearly with the DC current value upon "ON-OFF" switching. Compared to the Hall-effect based sensing, this method has the advantages of no need of driving voltage or cord separators even for two-wire appliance cords. Apart from the conventional consumer electronics, this method may have a wide application foreground in the new emerging fields, such as energy vehicles, lithium ion battery, or smart power grid.

  5. Electrical Anomalies Observed During DC3

    NASA Technical Reports Server (NTRS)

    Lang, Timothy J.; Rutledge, Steven A.; Dolan, Brenda; Krehbiel, Paul; Rison, William; Lindsey, Daniel T.; Lyons, Walt

    2013-01-01

    The primary scientific goals of DC3 involved improving our understanding of the chemical impacts of thunderstorms and their anvils. However, the Colorado domain provided opportunities to study other interesting phenomena, including the potential impacts of smoke ingestion on convection and thunderstorms, electrification processes in smoke plumes and pyrocumulonimbus clouds, and the production of sprites by unconventional thunderstorm.

  6. Manufacturing development of DC-10 advanced rudder

    NASA Technical Reports Server (NTRS)

    Cominsky, A.

    1979-01-01

    The design, manufacture, and ground test activities during development of production methods for an advanced composite rudder for the DC-10 transport aircraft are described. The advanced composite aft rudder is satisfactory for airline service and a cost saving in a full production manufacturing mode is anticipated.

  7. Computerized Torque Control for Large dc Motors

    NASA Technical Reports Server (NTRS)

    Willett, Richard M.; Carroll, Michael J.; Geiger, Ronald V.

    1987-01-01

    Speed and torque ranges in generator mode extended. System of shunt resistors, electronic switches, and pulse-width modulation controls torque exerted by large, three-phase, electronically commutated dc motor. Particularly useful for motor operating in generator mode because it extends operating range to low torque and high speed.

  8. Gravity Compensation Technique Uses Small dc Motor

    NASA Technical Reports Server (NTRS)

    Hollow, Richard

    1988-01-01

    Small dc servomotor powered by simple constant-current source and with suitable gearing used to cancel effect of gravity upon load. Lead-screw positioning system has load counterbalanced by small supplementary motor powered by constant current source. Motor lighter and more compact alternative to counterbalance. Used in variety of mechanical systems where load positioned or accelerated in vertical plane.

  9. Halbach array DC motor/generator

    DOEpatents

    Merritt, B.T.; Dreifuerst, G.R.; Post, R.F.

    1998-01-06

    A new configuration of DC motor/generator is based on a Halbach array of permanent magnets. This motor does not use ferrous materials so that the only losses are winding losses and losses due to bearings and windage. An ``inside-out`` design is used as compared to a conventional motor/generator design. The rotating portion, i.e., the rotor, is on the outside of the machine. The stationary portion, i.e., the stator, is formed by the inside of the machine. The rotor contains an array of permanent magnets that provide a uniform field. The windings of the motor are placed in or on the stator. The stator windings are then ``switched`` or ``commutated`` to provide a DC motor/generator much the same as in a conventional DC motor. The commutation can be performed by mechanical means using brushes or by electronic means using switching circuits. The invention is useful in electric vehicles and adjustable speed DC drives. 17 figs.

  10. Halbach array DC motor/generator

    DOEpatents

    Merritt, Bernard T.; Dreifuerst, Gary R.; Post, Richard F.

    1998-01-01

    A new configuration of DC motor/generator is based on a Halbach array of permanent magnets. This motor does not use ferrous materials so that the only losses are winding losses and losses due to bearings and windage. An "inside-out" design is used as compared to a conventional motor/generator design. The rotating portion, i.e., the rotor, is on the outside of the machine. The stationary portion, i.e., the stator, is formed by the inside of the machine. The rotor contains an array of permanent magnets that provide a uniform field. The windings of the motor are placed in or on the stator. The stator windings are then "switched" or "commutated" to provide a DC motor/generator much the same as in a conventional DC motor. The commutation can be performed by mechanical means using brushes or by electronic means using switching circuits. The invention is useful in electric vehicles and adjustable speed DC drives.

  11. DC3 Data and Information Page

    Atmospheric Science Data Center

    2015-03-16

    ... species, and d) chemistry in the anvil. To quantify the changes in chemistry and composition after active convection, focusing on a) ... hours after convection and b) the seasonal transition of the chemical composition of the upper troposphere.   The DC3 aircraft ...

  12. Climate and fishing steer ecosystem regeneration to uncertain economic futures

    PubMed Central

    Blenckner, Thorsten; Llope, Marcos; Möllmann, Christian; Voss, Rudi; Quaas, Martin F.; Casini, Michele; Lindegren, Martin; Folke, Carl; Chr. Stenseth, Nils

    2015-01-01

    Overfishing of large predatory fish populations has resulted in lasting restructurings of entire marine food webs worldwide, with serious socio-economic consequences. Fortunately, some degraded ecosystems show signs of recovery. A key challenge for ecosystem management is to anticipate the degree to which recovery is possible. By applying a statistical food-web model, using the Baltic Sea as a case study, we show that under current temperature and salinity conditions, complete recovery of this heavily altered ecosystem will be impossible. Instead, the ecosystem regenerates towards a new ecological baseline. This new baseline is characterized by lower and more variable biomass of cod, the commercially most important fish stock in the Baltic Sea, even under very low exploitation pressure. Furthermore, a socio-economic assessment shows that this signal is amplified at the level of societal costs, owing to increased uncertainty in biomass and reduced consumer surplus. Specifically, the combined economic losses amount to approximately 120 million € per year, which equals half of today's maximum economic yield for the Baltic cod fishery. Our analyses suggest that shifts in ecological and economic baselines can lead to higher economic uncertainty and costs for exploited ecosystems, in particular, under climate change. PMID:25694626

  13. Predictive and Neural Predictive Control of Uncertain Systems

    NASA Technical Reports Server (NTRS)

    Kelkar, Atul G.

    2000-01-01

    Accomplishments and future work are:(1) Stability analysis: the work completed includes characterization of stability of receding horizon-based MPC in the setting of LQ paradigm. The current work-in-progress includes analyzing local as well as global stability of the closed-loop system under various nonlinearities; for example, actuator nonlinearities; sensor nonlinearities, and other plant nonlinearities. Actuator nonlinearities include three major types of nonlineaxities: saturation, dead-zone, and (0, 00) sector. (2) Robustness analysis: It is shown that receding horizon parameters such as input and output horizon lengths have direct effect on the robustness of the system. (3) Code development: A matlab code has been developed which can simulate various MPC formulations. The current effort is to generalize the code to include ability to handle all plant types and all MPC types. (4) Improved predictor: It is shown that MPC design using better predictors that can minimize prediction errors. It is shown analytically and numerically that Smith predictor can provide closed-loop stability under GPC operation for plants with dead times where standard optimal predictor fails. (5) Neural network predictors: When neural network is used as predictor it can be shown that neural network predicts the plant output within some finite error bound under certain conditions. Our preliminary study shows that with proper choice of update laws and network architectures such bound can be obtained. However, much work needs to be done to obtain a similar result in general case.

  14. Climate and fishing steer ecosystem regeneration to uncertain economic futures.

    PubMed

    Blenckner, Thorsten; Llope, Marcos; Möllmann, Christian; Voss, Rudi; Quaas, Martin F; Casini, Michele; Lindegren, Martin; Folke, Carl; Chr Stenseth, Nils

    2015-03-22

    Overfishing of large predatory fish populations has resulted in lasting restructurings of entire marine food webs worldwide, with serious socio-economic consequences. Fortunately, some degraded ecosystems show signs of recovery. A key challenge for ecosystem management is to anticipate the degree to which recovery is possible. By applying a statistical food-web model, using the Baltic Sea as a case study, we show that under current temperature and salinity conditions, complete recovery of this heavily altered ecosystem will be impossible. Instead, the ecosystem regenerates towards a new ecological baseline. This new baseline is characterized by lower and more variable biomass of cod, the commercially most important fish stock in the Baltic Sea, even under very low exploitation pressure. Furthermore, a socio-economic assessment shows that this signal is amplified at the level of societal costs, owing to increased uncertainty in biomass and reduced consumer surplus. Specifically, the combined economic losses amount to approximately 120 million € per year, which equals half of today's maximum economic yield for the Baltic cod fishery. Our analyses suggest that shifts in ecological and economic baselines can lead to higher economic uncertainty and costs for exploited ecosystems, in particular, under climate change.

  15. Evaluation of modern IGBT-modules for hard-switched AC/DC/AC converters

    SciTech Connect

    Blaabjerg, F.; Pedersen, J.K.; Jaeger, U.

    1995-12-31

    The development of IGBT devices is still producing faster devices with lower losses. The applications become more advanced like a complete hard-switched AC/DC/AC converter with almost clean input current and regenerating capabilities. This paper will first focus on a detailed characterization and comparison of eight different IGBT-modules representing state-of-the-art for both PT and NPT technologies. The voltage level of the devices is 1,200V and 1,600V/1,700V. The characterization is done on an advanced measurement system which is briefly described. The characterization is based on static and dynamic tests for both IGBT and the diodes in the IGBT-modules at a junction temperature at 125 C. The comparison is first done directly based on conduction losses and switching losses, and later the measurements are used in a loss model for a complete AC/DC/AC converter application. In the AC/DC/AC converter the power losses are modelled, and different operating conditions are compared like different voltage levels in the DC-link. It is concluded dependent on operation conditions different devices will be preferable, but the high voltage devices have the highest losses even at a high operating voltage.

  16. Multi-KW dc distribution system technology research study

    NASA Technical Reports Server (NTRS)

    Dawson, S. G.

    1978-01-01

    The Multi-KW DC Distribution System Technology Research Study is the third phase of the NASA/MSFC study program. The purpose of this contract was to complete the design of the integrated technology test facility, provide test planning, support test operations and evaluate test results. The subjet of this study is a continuation of this contract. The purpose of this continuation is to study and analyze high voltage system safety, to determine optimum voltage levels versus power, to identify power distribution system components which require development for higher voltage systems and finally to determine what modifications must be made to the Power Distribution System Simulator (PDSS) to demonstrate 300 Vdc distribution capability.

  17. Modeling of brushless dc generating systems using diakoptics

    NASA Astrophysics Data System (ADS)

    Vadher, Vinod; Gregory, Keith; Kettleborough, J. G.; Smith, Ivor R.

    1993-01-01

    The mathematical modeling of a brushless dc generator is described, as an illustration of the application of diakoptic techniques to the analysis of small-scale electrical power supply systems. Modeling of the generator and its output rectifier is accomplished using an established matrix technique that accounts for the continuously changing conduction pattern of the diode bridge network. The advantages of using diakoptics are introduced when consideration is given to the main generator linked to its exciter and to the automatic voltage regulator and permanent magnet generator which are often included in a complete unit. A solution algorithm is presented for this overall arrangement and a comparison is made between theoretical and practical results for a typical 3-stage 4000 rev/min 10.3 kW 28 V unit.

  18. DC multi-infeed study. Final report

    SciTech Connect

    Szechtman, M.; Pilotto, L.A.S.; Ping, W.W.; Salgado, E.; Dias de Carvalho, A.R.C.; Long, W.F.; Alvarado, F.L.; DeMarco, C.L.; Canizares, C.A.; Wey, A.

    1994-12-01

    An HVdc multiconverter configuration results when more than one converter station is located within the same electrical region. Such a situation will be a natural consequence of the growing use of the HVdc technology. Relevant questions relating to multiconverter configurations have been analyzed in the scope of this research project. In particular, special emphasis has been devoted to the HVdc inverter multiinfeed schemes, since such a situation will be more commonly found in future applications and usually results in the most severe ac/dc interactions. The main purpose of this project is to present a general insight into the potential problems resulting from multiinfeed HVdc operation, using networks based on realistic power system configurations. Power system studies have been performed using several digital (Load-Flow, Transient Stability, Eigenvalue and EMTP programs) and analog (DC Simulator) tools in a complementary basis to investigate both low and high frequency interaction phenomena. The project was conducted to evaluate the technical aspects of the various ac/dc and dc/dc interactions. It addressed small signal stability, an overview of the entire system transient and dynamic stability, some aspects of the ac voltage stability problem and HVdc control stability including the effects of the VDCOL units and possible occurrence of commutation failures at inverter stations after recovery from faults. This report identifies the potential problems resulting from multiinfeed situations and proposes practical solutions. It also presents a survey on how the various HVdc system controllers can be coordinated to provide the interconnected ac system with an improved dynamic performance, a high level of operational flexibility and the maximization of the overall system loadability.

  19. Cryogenic Evaluation of an Advanced DC/DC Converter Module for Deep Space Applications

    NASA Technical Reports Server (NTRS)

    Elbuluk, Malik E.; Hammoud, Ahmad; Gerber, Scott S.; Patterson, Richard

    2003-01-01

    DC/DC converters are widely used in power management, conditioning, and control of space power systems. Deep space applications require electronics that withstand cryogenic temperature and meet a stringent radiation tolerance. In this work, the performance of an advanced, radiation-hardened (rad-hard) commercial DC/DC converter module was investigated at cryogenic temperatures. The converter was investigated in terms of its steady state and dynamic operations. The output voltage regulation, efficiency, terminal current ripple characteristics, and output voltage response to load changes were determined in the temperature range of 20 to -140 C. These parameters were obtained at various load levels and at different input voltages. The experimental procedures along with the results obtained on the investigated converter are presented and discussed.

  20. DC-DC power converter research for Orbiter/Station power exchange

    NASA Technical Reports Server (NTRS)

    Ehsani, M.

    1993-01-01

    This project was to produce innovative DC-DC power converter concepts which are appropriate for the power exchange between the Orbiter and the Space Station Freedom (SSF). The new converters must interface three regulated power buses on SSF, which are at different voltages, with three fuel cell power buses on the Orbiter which can be at different voltages and should be tracked independently. Power exchange is to be bi-directional between the SSF and the Orbiter. The new converters must satisfy the above operational requirements with better weight, volume, efficiency, and reliability than is available from the present conventional technology. Two families of zero current DC-DC converters were developed and successfully adapted to this application. Most of the converters developed are new and are presented.

  1. Research of digital controlled DC/DC converter based on STC12C5410AD

    NASA Astrophysics Data System (ADS)

    Chen, Dan-Jiang; Jin, Xin; Xiao, Zhi-Hong

    2010-02-01

    In order to study application of digital control technology on DC/DC converter, principle of increment mode PID control algorithm was analyzed in the paper. Then, a SCM named STC12C5410AD was introduced with its internal resources and characteristics. The PID control algorithm can be implemented easily based on it. The output of PID control was used to change the value of a variable that is 255 times than duty cycle, and this reduced the error of calculation. The valid of the presented algorithm was verified by an experiment for a BUCK DC/DC converter. The experimental results indicated that output voltage of the BUCK converter is stable with low ripple.

  2. GaN HFET-Based DC/DC Converters for Low Power RF Satellite Equipment

    NASA Astrophysics Data System (ADS)

    Delamare, Guillaume; Maynadier, Paul; Schneider, Henri

    2014-08-01

    This paper presents the evaluation and prototyping of a low power, multiple outputs, isolated DC/DC converter for 100 V telecom satellite applications, using enhancement-mode GaN heterostructure field effect transistors (HFETs) to enable 1 MHz switching frequencies.Radiation-hardened power MOSFETs are currently the main drivers for both cost and size (because of their limited switching frequency) of existing DC/DC converters. Commercially available normally-off GaN HFETs are very promising replacements, thanks to their high switching speed and intrinsic radiation hardness.In this study different designs, built around various isolated topologies, were compared for a typical low power RF application (10W) with a switching frequency of 1 MHz. Calculations and simulations helped select the most adequate architecture in terms of size and efficiency. A prototype was then built and its performance measured. Electromagnetic compatibility was evaluated by mating the power supply to its RF equipment.

  3. SUBCONTRACT REPORT: DC-DC Converter for Fuel Cell and Hybrid Vehicles

    SciTech Connect

    Marlino, Laura D; Zhu, Lizhi

    2007-07-01

    The goal of this project is to develop and fabricate a 5kW dc-dc converter with a baseline 14V output capability for fuel cell and hybrid vehicles. The major objectives for this dc-dc converter technology are to meet: Higher efficiency (92%); High coolant temperature,e capability (105 C); High reliability (15 Years/150,000miles); Smaller volume (5L); Lower weight (6kg); and Lower cost ($75/kW). The key technical challenge for these converters is the 105 C coolant temperatures. The power switches and magnetics must be designed to sustain these operating temperatures reliably, without a large cost/mass/volume penalty.

  4. Switched capacitor DC-DC converter ASICs for the upgraded LHC trackers

    NASA Astrophysics Data System (ADS)

    Bochenek, M.; Dabrowski, W.; Faccio, F.; Michelis, S.

    2010-12-01

    The High Luminosity Upgrade of the ATLAS Inner Tracker puts demanding requirements on the powering system of the silicon strip detector modules due to 10-fold increase of the channel count compared to the existing SemiConductor Tracker. Therefore, new solutions for the powering scheme must be elaborated. Currently two possible approaches, the serial powering and the parallel powering scheme using the DC-DC conversion technique, are under development. This paper describes two switched capacitor DC-DC converters designed in a 130 nm technology. For the optimized step-down converter, foreseen for the parallel powering scheme, power efficiency of 97% has been achieved, while for the charge pump, designed for the serial powering scheme, power efficiency of 85% has been achieved.

  5. Beyond complete positivity

    NASA Astrophysics Data System (ADS)

    Dominy, Jason M.; Lidar, Daniel A.

    2016-04-01

    We provide a general and consistent formulation for linear subsystem quantum dynamical maps, developed from a minimal set of postulates, primary among which is a relaxation of the usual, restrictive assumption of uncorrelated initial system-bath states. We describe the space of possibilities admitted by this formulation, namely that, far from being limited to only completely positive (CP) maps, essentially any C-linear, Hermiticity-preserving, trace-preserving map can arise as a legitimate subsystem dynamical map from a joint unitary evolution of a system coupled to a bath. The price paid for this added generality is a trade-off between the set of admissible initial states and the allowed set of joint system-bath unitary evolutions. As an application, we present a simple example of a non-CP map constructed as a subsystem dynamical map that violates some fundamental inequalities in quantum information theory, such as the quantum data processing inequality.

  6. Completely bootstrapped tokamak

    SciTech Connect

    Weening, R.H. ); Boozer, A.H. )

    1992-01-01

    Numerical simulations of the evolution of large-scale magnetic fields have been developed using a mean-field Ohm's law. The Ohm's law is coupled to a {Delta}{prime} stabilty analysis and a magnetic island growth equation in order to simulate the behavior of tokamak plasmas that are subject to tearing modes. In one set of calculations, the magnetohydrodynamic (MHD)-stable regime of the tokamak is examined via the construction of an {ital l}{sub {ital i}} -{ital q}{sub {ital a}} diagram. The results confirm previous calculations that show that tearing modes introduce a stability boundary into the {ital l}{sub {ital i}} -{ital q}{sub {ital a}} space. In another series of simulations, the interaction between tearing modes and the bootstrap current is investigated. The results indicate that a completely bootstrapped tokamak may be possible, even in the absence of any externally applied loop voltage or current drive.

  7. Intelligent robust control for uncertain nonlinear time-varying systems and its application to robotic systems.

    PubMed

    Chang, Yeong-Chan

    2005-12-01

    This paper addresses the problem of designing adaptive fuzzy-based (or neural network-based) robust controls for a large class of uncertain nonlinear time-varying systems. This class of systems can be perturbed by plant uncertainties, unmodeled perturbations, and external disturbances. Nonlinear H(infinity) control technique incorporated with adaptive control technique and VSC technique is employed to construct the intelligent robust stabilization controller such that an H(infinity) control is achieved. The problem of the robust tracking control design for uncertain robotic systems is employed to demonstrate the effectiveness of the developed robust stabilization control scheme. Therefore, an intelligent robust tracking controller for uncertain robotic systems in the presence of high-degree uncertainties can easily be implemented. Its solution requires only to solve a linear algebraic matrix inequality and a satisfactorily transient and asymptotical tracking performance is guaranteed. A simulation example is made to confirm the performance of the developed control algorithms.

  8. Quasimodes instability analysis of uncertain asymmetric rotor system based on 3D solid element model

    NASA Astrophysics Data System (ADS)

    Zuo, Yanfei; Wang, Jianjun; Ma, Weimeng

    2017-03-01

    Uncertainties are considered in the equation of motion of an asymmetric rotor system. Based on Hill's determinant method, quasimodes stability analysis with uncertain parameters is used to get stochastic boundaries of unstable regions. Firstly, A 3D finite element rotor model was built in rotating frame with four parameterized coefficients, which is assumed as random parameters representing the uncertainties existing in the rotor system. Then the influences of uncertain coefficients on the distribution of the unstable region boundaries are analyzed. The results show that uncertain parameters have various influences on the size, boundary and number of unstable regions. At last, the statistic results of the minimum and maximum spin speeds of unstable regions were got by Monte Carlo simulation. The used method is suitable for real engineering rotor system, because arbitrary configuration of rotors can be modeled by 3D finite element.

  9. Subspace electrode selection methodology for EEG multiple source localization error reduction due to uncertain conductivity values.

    PubMed

    Crevecoeur, Guillaume; Yitembe, Bertrand; Dupre, Luc; Van Keer, Roger

    2013-01-01

    This paper proposes a modification of the subspace correlation cost function and the Recursively Applied and Projected Multiple Signal Classification (RAP-MUSIC) method for electroencephalography (EEG) source analysis in epilepsy. This enables to reconstruct neural source locations and orientations that are less degraded due to the uncertain knowledge of the head conductivity values. An extended linear forward model is used in the subspace correlation cost function that incorporates the sensitivity of the EEG potentials to the uncertain conductivity value parameter. More specifically, the principal vector of the subspace correlation function is used to provide relevant information for solving the EEG inverse problems. A simulation study is carried out on a simplified spherical head model with uncertain skull to soft tissue conductivity ratio. Results show an improvement in the reconstruction accuracy of source parameters compared to traditional methodology, when using conductivity ratio values that are different from the actual conductivity ratio.

  10. A linear quadratic regulator approach to the stabilization of uncertain linear systems

    NASA Technical Reports Server (NTRS)

    Shieh, L. S.; Sunkel, J. W.; Wang, Y. J.

    1990-01-01

    This paper presents a linear quadratic regulator approach to the stabilization of uncertain linear systems. The uncertain systems under consideration are described by state equations with the presence of time-varying unknown-but-bounded uncertainty matrices. The method is based on linear quadratic regulator (LQR) theory and Liapunov stability theory. The robust stabilizing control law for a given uncertain system can be easily constructed from the symmetric positive-definite solution of the associated augmented Riccati equation. The proposed approach can be applied to matched and/or mismatched systems with uncertainty matrices in which only their matrix norms are bounded by some prescribed values and/or their entries are bounded by some prescribed constraint sets. Several numerical examples are presented to illustrate the results.

  11. Performance analysis of active disturbance rejection tracking control for a class of uncertain LTI systems.

    PubMed

    Xue, Wenchao; Huang, Yi

    2015-09-01

    The paper considers the tracking problem for a class of uncertain linear time invariant (LTI) systems with both uncertain parameters and external disturbances. The active disturbance rejection tracking controller is designed and the resulting closed-loop system's characteristics are comprehensively studied. In the time-domain, it is proven that the output of closed-loop system can approach its ideal trajectory in the transient process against different kinds of uncertainties by tuning the bandwidth of extended state observer (ESO). In the frequency-domain, different kinds of parameters' influences on the phase margin and the crossover frequency of the resulting control system are illuminated. Finally, the effectiveness and robustness of the controller are verified through the actuator position control system with uncertain parameters and load disturbances in the simulations.

  12. Design of a Multiple-Input SC DC-DC Converter Realizing Long Battery Runtime

    NASA Astrophysics Data System (ADS)

    Eguchi, Kei; Pongswatd, Sawai; Julsereewong, Amphawan; Tirasesth, Kitti; Sasaki, Hirofumi; Inoue, Takahiro

    A multiple-input switched-capacitor DC-DC converter which can realize long battery runtime is proposed in this letter. Unlike conventional converters for a back-lighting application, the proposed converter drives some LEDs by converting energy from solar cells. Furthermore, the proposed converter can charge a lithium battery when an output load is light. The validity of circuit design is confirmed by theoretical analyses, simulations, and experiments.

  13. Efficiency and weight of voltage multiplier type ultra lightweight dc-dc converters

    NASA Technical Reports Server (NTRS)

    Harrigill, W. T., Jr.; Myers, I. T.

    1975-01-01

    An analytical and experimental study was made of a capacitor-diode voltage multiplier without a transformer which offers the possibility of high efficiency with light weight. The dc-dc conversion efficiencies of about 94 percent were achieved at output powers of 150 watts at 1000 volts using 8x multiplication. A detailed identification of losses was made, including forward drop losses in component, switching losses, reverse junction capacitance charging losses, and charging losses in the main ladder capacitors.

  14. Sliding-mode control of single input multiple output DC-DC converter

    NASA Astrophysics Data System (ADS)

    Zhang, Libo; Sun, Yihan; Luo, Tiejian; Wan, Qiyang

    2016-10-01

    Various voltage levels are required in the vehicle mounted power system. A conventional solution is to utilize an independent multiple output DC-DC converter whose cost is high and control scheme is complicated. In this paper, we design a novel SIMO DC-DC converter with sliding mode controller. The proposed converter can boost the voltage of a low-voltage input power source to a controllable high-voltage DC bus and middle-voltage output terminals, which endow the converter with characteristics of simple structure, low cost, and convenient control. In addition, the sliding mode control (SMC) technique applied in our converter can enhance the performances of a certain SIMO DC-DC converter topology. The high-voltage DC bus can be regarded as the main power source to the high-voltage facility of the vehicle mounted power system, and the middle-voltage output terminals can supply power to the low-voltage equipment on an automobile. In the respect of control algorithm, it is the first time to propose the SMC-PID (Proportion Integration Differentiation) control algorithm, in which the SMC algorithm is utilized and the PID control is attended to the conventional SMC algorithm. The PID control increases the dynamic ability of the SMC algorithm by establishing the corresponding SMC surface and introducing the attached integral of voltage error, which endow the sliding-control system with excellent dynamic performance. At last, we established the MATLAB/SIMULINK simulation model, tested performance of the system, and built the hardware prototype based on Digital Signal Processor (DSP). Results show that the sliding mode control is able to track a required trajectory, which has robustness against the uncertainties and disturbances.

  15. Sliding-mode control of single input multiple output DC-DC converter.

    PubMed

    Zhang, Libo; Sun, Yihan; Luo, Tiejian; Wan, Qiyang

    2016-10-01

    Various voltage levels are required in the vehicle mounted power system. A conventional solution is to utilize an independent multiple output DC-DC converter whose cost is high and control scheme is complicated. In this paper, we design a novel SIMO DC-DC converter with sliding mode controller. The proposed converter can boost the voltage of a low-voltage input power source to a controllable high-voltage DC bus and middle-voltage output terminals, which endow the converter with characteristics of simple structure, low cost, and convenient control. In addition, the sliding mode control (SMC) technique applied in our converter can enhance the performances of a certain SIMO DC-DC converter topology. The high-voltage DC bus can be regarded as the main power source to the high-voltage facility of the vehicle mounted power system, and the middle-voltage output terminals can supply power to the low-voltage equipment on an automobile. In the respect of control algorithm, it is the first time to propose the SMC-PID (Proportion Integration Differentiation) control algorithm, in which the SMC algorithm is utilized and the PID control is attended to the conventional SMC algorithm. The PID control increases the dynamic ability of the SMC algorithm by establishing the corresponding SMC surface and introducing the attached integral of voltage error, which endow the sliding-control system with excellent dynamic performance. At last, we established the MATLAB/SIMULINK simulation model, tested performance of the system, and built the hardware prototype based on Digital Signal Processor (DSP). Results show that the sliding mode control is able to track a required trajectory, which has robustness against the uncertainties and disturbances.

  16. Department of Defense Cost Analysis Symposium (26th) on Cost Analysis in an Uncertain Defense Environment Held in Washington, DC on 9-11 September 1992

    DTIC Science & Technology

    1992-09-09

    American Institute of Aeronautics and Astronautics; the Board of Directors of the Michigan Opera Theatre ; and the National Executive Board of the Boy Scouts...NSION PROGRA S ON FORSIGN MILITARY BALES A recurring question in fleet management is when to extend the service lives of aging trucks. This paper will...costs and performance over time. The " baroque arsenal" hypothesis predicts increasing marginal costs of performance over time, which a "rational

  17. Static DC to DC Power Conditioning-Active Ripple Filter, 1 MHZ DC to DC Conversion, and Nonlinear Analysis. Ph.D. Thesis; [voltage regulation and conversion circuitry for spacecraft power supplies

    NASA Technical Reports Server (NTRS)

    Sander, W. A., III

    1973-01-01

    Dc to dc static power conditioning systems on unmanned spacecraft have as their inputs highly fluctuating dc voltages which they condition to regulated dc voltages. These input voltages may be less than or greater than the desired regulated voltages. The design of two circuits which address specific problems in the design of these power conditioning systems and a nonlinear analysis of one of the circuits are discussed. The first circuit design is for a nondissipative active ripple filter which uses an operational amplifier to amplify and cancel the sensed ripple voltage. A dc to dc converter operating at a switching frequency of 1 MHz is the second circuit discussed. A nonlinear analysis of the type of dc to dc converter utilized in designing the 1 MHz converter is included.

  18. ITAR Free Commercial-of-the-Shelf DC/DC Converter

    NASA Astrophysics Data System (ADS)

    Denzinger, Wolfgang; Hintze, Thomas

    2014-08-01

    A commercial-of-the-shelf (COTS) DC/DC converter for digital space equipment has been developed by ASP under ESA contract with special emphasis on low cost, no use of ITAR listed EEE parts like Mosfets, minimum number of rad-hard digital IC's and a design tolerance against single event effects by appropriate filtering. However, the intention to qualify this discrete converter design for a low cost FM series production was difficult due to the high up-sceening cost of EEE-parts with one lot guarantee and minimum-by. To overcome this problem, in a next step a redesign of the DC/DC converter was performed with all semiconductors like bipolar transistors, rectifiers and zener diodes packaged into hybrids. With this approach it was possible to buy a high number of less expensive wafers or dies from one lot, to perform a lot acceptance test and to integrate the dies into hybrid packages with further up- screening for FM use. The semiconductors have been packaged into three signal hybrids with 44 pins and one power hybrid with 24 pins for the dissipating transistors and rectifiers. The design of the hybrids is such, that all integrated semiconductors can be tested individually. The qualification of four EQM DC/DC converters with different combinations of output voltages has been successfully performed and two FM's have been manufactured and tested.

  19. Materials Testing on the DC-X and DC-XA

    NASA Technical Reports Server (NTRS)

    Smith, Dane; Carroll, Carol; Marschall, Jochen; Pallix, Joan

    1997-01-01

    Flight testing of thermal protection materials has been carried out over a two year period on the base heat shield of the Delta Clipper (DC-X and DC-XA), as well on a body flap. The purpose was to use the vehicle as a test bed for materials and more efficient repair or maintenance processes which would be potentially useful for application on new entry vehicles (i.e., X-33, RLV, planetary probes), as well as on the existing space shuttle orbiters. Panels containing Thermal Protection Systems (TPS) and/or structural materials were constructed either at NASA Ames Research Center or at McDonnell Douglas Aerospace (MDA) and attached between two of the four thrusters in the base heat shield of the DC-X or DC-XA. Three different panels were flown on DC-X flights 6, 7, and 8. A total of 7 panels were flown on DC-XA flights 1, 2, and 3. The panels constructed at Ames contained a variety of ceramic TPS including flexible blankets, tiles with high emissivity coatings, lightweight ceramic ablators and other ceramic composites. The MDS test panels consisted primarily of a variety of metallic composites. This report focuses on the ceramic TPS test results.

  20. Design of synchronization technique for uncertain discrete network group with diverse structures

    NASA Astrophysics Data System (ADS)

    Lü, Ling; Li, Chengren; Li, Gang; Sun, Ao; Yan, Zhe; Rong, Tingting; Gao, Yan

    2017-01-01

    In this work, we design a novel synchronization technique to realize the synchronization of the network group which is constituted by some uncertain discrete networks with diverse structures. Based on Lyapunov theorem, the selection principle of the control inputs and identification law of uncertain parameters in networks are determined, and the synchronization conditions of network group are obtained. Finally, numerical simulations using one-dimensional convective equations with spatiotemporal chaos behaviors illustrate the performance of the synchronization scheme. The research results show that our synchronization technique can be suitable for the network connecting arbitrarily, and not only the network number but also node number in each network can also be chosen freely.

  1. Evaluation of Ares-I Control System Robustness to Uncertain Aerodynamics and Flex Dynamics

    NASA Technical Reports Server (NTRS)

    Jang, Jiann-Woei; VanTassel, Chris; Bedrossian, Nazareth; Hall, Charles; Spanos, Pol

    2008-01-01

    This paper discusses the application of robust control theory to evaluate robustness of the Ares-I control systems. Three techniques for estimating upper and lower bounds of uncertain parameters which yield stable closed-loop response are used here: (1) Monte Carlo analysis, (2) mu analysis, and (3) characteristic frequency response analysis. All three methods are used to evaluate stability envelopes of the Ares-I control systems with uncertain aerodynamics and flex dynamics. The results show that characteristic frequency response analysis is the most effective of these methods for assessing robustness.

  2. Dynamic neural network-based robust observers for uncertain nonlinear systems.

    PubMed

    Dinh, H T; Kamalapurkar, R; Bhasin, S; Dixon, W E

    2014-12-01

    A dynamic neural network (DNN) based robust observer for uncertain nonlinear systems is developed. The observer structure consists of a DNN to estimate the system dynamics on-line, a dynamic filter to estimate the unmeasurable state and a sliding mode feedback term to account for modeling errors and exogenous disturbances. The observed states are proven to asymptotically converge to the system states of high-order uncertain nonlinear systems through Lyapunov-based analysis. Simulations and experiments on a two-link robot manipulator are performed to show the effectiveness of the proposed method in comparison to several other state estimation methods.

  3. Macular pigmentation of uncertain aetiology revisited: two case reports and a proposed algorithm for clinical classification.

    PubMed

    Chandran, Veena; Kumarasinghe, Sujith Prasad

    2017-02-01

    Ashy dermatosis, erythema dyschromicum perstans, lichen planus pigmentosus and idiopathic eruptive macular pigmentation are various types of acquired macular hyperpigmentation disorders of the skin described in literature. However, a global consensus on the definitions of these entities is lacking. We report two cases of acquired macular (hyper)pigmentation of uncertain aetiology diagnosed as ashy dermatosis and attempt to clarify the various confusing nosologies based on existing literature. We infer that acquired small and large macular pigmentation of uncertain aetiology should be considered separate from that associated with lichen planus. We also propose a diagnostic algorithm for patients with acquired macular hyperpigmentation.

  4. Stability of uncertain impulsive complex-variable chaotic systems with time-varying delays.

    PubMed

    Zheng, Song

    2015-09-01

    In this paper, the robust exponential stabilization of uncertain impulsive complex-variable chaotic delayed systems is considered with parameters perturbation and delayed impulses. It is assumed that the considered complex-variable chaotic systems have bounded parametric uncertainties together with the state variables on the impulses related to the time-varying delays. Based on the theories of adaptive control and impulsive control, some less conservative and easily verified stability criteria are established for a class of complex-variable chaotic delayed systems with delayed impulses. Some numerical simulations are given to validate the effectiveness of the proposed criteria of impulsive stabilization for uncertain complex-variable chaotic delayed systems.

  5. Simulation and Performance of Brushless DC Motor Actuators.

    DTIC Science & Technology

    1985-12-01

    AD-RI63 725 SIMULATION AND PERFORMANCE OF IRUSHLESS DC MOTOR ACTUATORS(U) NAVAL POSTGRADUATE SCHOOL MONTEREY CA A GERDA DEC 85 NPS69-85-628 M...California Progress Report SIMULATION AND PERFORMANCE OF BRUSHLESS DC MOTOR ACTUATORS IN SUPPORT OF THE PROGRAM "ADVANCED MISSILE CONTROL DEVICES"I of...34.’ SIMULATION AND PERFORMANCE OF BRUSHLESS DC MOTOR ACTUATORS SUMMARY The simulation model for a Brushless D.C. Motor and the associated * commutation power

  6. 76 FR 52602 - Drawbridge Operation Regulation; Anacostia River, Washington, DC

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-23

    ..., Washington, DC AGENCY: Coast Guard, DHS. ACTION: Notice of proposed rulemaking. SUMMARY: The Coast Guard... the Anacostia River, mile 3.4 at Washington, DC. The proposed change will alter the eight hour advance..., SE., Washington, DC 20590-0001. (4) Hand delivery: Same as mail address above, between 9 a.m. and 5...

  7. 76 FR 52566 - Drawbridge Operation Regulations; Anacostia River, Washington, DC

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-23

    ... SECURITY Coast Guard 33 CFR Part 117 Drawbridge Operation Regulations; Anacostia River, Washington, DC... Washington, DC. This deviation will test a change to the drawbridge operation schedule to determine whether a..., SE., Washington, DC 20590-0001. (4) Hand delivery: Same as mail address above, between 9 a.m. and 5...

  8. 77 FR 25781 - Environmental Impact Statement; Washington, DC

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-01

    ... Federal Highway Administration Environmental Impact Statement; Washington, DC AGENCY: U.S. Federal Highway... Washington, DC is issuing this notice to advise agencies and the public that a Draft Environmental Impact... Avenue Tunnel in Washington, DC. The tunnel is owned and operated by CSX Transportation, Inc. (CSX),...

  9. 77 FR 14968 - Drawbridge Operation Regulation; Anacostia River, Washington, DC

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-14

    ..., Washington, DC AGENCY: Coast Guard, DHS. ACTION: Final rule. SUMMARY: The Coast Guard is changing the..., mile 3.4, at Washington, DC. The change will alter the eight hour advance notice requirement for a... Avenue SE., Washington, DC 20590, between 9 a.m. and 5 p.m., Monday through Friday, except...

  10. Complete Genome Sequence of the Largest Known Flavi-Like Virus, Diaphorina citri flavi-like virus, a Novel Virus of the Asian Citrus Psyllid, Diaphorina citri

    PubMed Central

    Matsumura, Emilyn E.; Nerva, Luca; Nigg, Jared C.; Falk, Bryce W.

    2016-01-01

    A novel flavi-like virus tentatively named Diaphorina citri flavi-like virus (DcFLV) was identified in field populations of Diaphorina citri through small RNA and transcriptome sequencing followed by reverse transcription (RT)-PCR. We report here the complete nucleotide sequence and genome organization of DcFLV, the largest flavi-like virus identified to date. PMID:27609921

  11. A feed-forward controlled AC-DC boost converter for biomedical implants.

    PubMed

    Jiang, Hao; Lan, Di; Lin, Dahsien; Zhang, Junmin; Liou, Shyshenq; Shahnasser, Hamid; Shen, Ming; Harrison, Michael; Roy, Shuvo

    2012-01-01

    Miniaturization is important to make implants clinic friendly. Wireless power transfer is an essential technology to miniaturize implants by reducing their battery size or completely eliminating their batteries. Traditionally, a pair of inductively-coupled coils operating at radio-frequency (RF) is employed to deliver electrical power wirelessly. In this approach, a rectifier is needed to convert the received RF power to a stable DC one. To achieve high efficiency, the induced voltage of the receiving coil must be much higher than the turn-on voltage of the rectifying diode (which could be an active circuit for low turn-on voltage) [1]. In order to have a high induced voltage, the size of the receiving coil often is significantly larger than rest of the implant. A rotating magnets based wireless power transfer has been demonstrated to deliver the same amount of power at much lower frequency (around 100 Hz) because of the superior magnetic strength produced by rare-earth magnets [2]. Taking the advantage of the low operating frequency, an innovative feed-forward controlled AC to DC boost converter has been demonstrated for the first time to accomplish the following two tasks simultaneously: (1) rectifying the AC power whose amplitude (500 mV) is less than the rectifier's turn-on voltage (1.44 V) and (2) boosting the DC output voltage to a much higher level (5 V). Within a range, the output DC voltage can be selected by the control circuit. The standard deviation of the output DC voltage is less than 2.1% of its mean. The measured load regulation is 0.4 V/kΩ. The estimated conversion efficiency excluding the power consumption of the control circuits reaches 75%. The converter in this paper has the potential to reduce the size of the receiving coil and yet achieve desirable DC output voltage for powering biomedical implants.

  12. Development of battery powered 100 kV dc power supply

    NASA Astrophysics Data System (ADS)

    Verma, Rishi; Shyam, A.; Nair, Lakshmi

    2006-10-01

    The increased interest in pulsed power field applications has generated the need for development of compact and remotely operated chargers driven by rechargeable batteries. With this objective, a compact and portable dc to dc Converter has been developed which has an output rating of 100kV, 0.4mA. The high voltage generation scheme uses a hybrid approach. The overall idea behind implementation of hybrid concept is to optimize voltage upliftment with suitable techniques for maximizing power delivered per unit volume. The proposed converter provides this feature and uses flyback converter in association with Cockcroft-Walton Multiplier [M. Jullian, Cockcroft-Walton Multiplier Optimum Design Guide V2.0, August 2005 (http//www.blazelabes.com)] for the generation of 100kV dc from 12V dc source, i.e., normal battery. In the first stage 12V dc is modulated/chopped into series of high frequency pulses by pulse width modulator and then increased in level up to 16kVpp by step up flyback transformer. Further by using n stage half wave series Cockcroft-Walton multiplier the voltage is stepped up to the level of 100kV. As switching device, state of the art metal-oxide-semiconductor field-effect transistor has been used. The obtained voltage multiplier cascade efficiency is 82.64%, whereas overall power conversion efficiency of the charging power supply is 85.47%. The control unit has been fiber optically isolated from high voltage unit due to safety consideration. The presented article explores complete design and development approach of compact and portable 100kV dc power supply which can be used for a variety of applications such as x-ray generation, ion implantation, charge particle acceleration, radio isotope production, etc.

  13. Keratinocyte galvanotaxis in combined DC and AC electric fields supports an electromechanical transduction sensing mechanism.

    PubMed

    Hart, Francis X; Laird, Mhairi; Riding, Aimie; Pullar, Christine E

    2013-02-01

    Sedentary keratinocytes at the edge of a skin wound migrate into the wound, guided by the generation of an endogenous electric field (EF) generated by the collapse of the transepithelial potential. The center of the wound quickly becomes more negative than the surrounding tissue and remains the cathode of the endogenous EF until the wound is completely re-epithelialized. This endogenous guidance cue can be studied in vitro. When placed in a direct current (DC) EF of physiological strength, 100 V/m, keratinocytes migrate directionally toward the cathode in a process known as galvanotaxis. Although a number of membrane-bound (e.g., epidermal growth factor receptor (EGFR), integrins) and cytosolic proteins (cAMP, ERK, PI3K) are known to play a role in the downstream signaling mechanisms underpinning galvanotaxis, the initial sensing mechanism for this response is not understood. To investigate the EF sensor, we studied the migration of keratinocytes in a DC EF of 100 V/m, alternating current (AC) EFs of 40 V/m at either 1.6 or 160 Hz, and combinations of DC and AC EFs. In the AC EFs alone, keratinocytes migrated randomly. The 1.6 Hz AC EF combined with the DC EF suppressed the direction of migration but had no effect on speed. In contrast, the 160 Hz AC EF combined with the DC EF did not affect the direction of migration but increased the migration speed compared to the DC EF alone. These results can be understood in terms of an electromechanical transduction model, but not an electrodiffusion/osmosis or a voltage-gated channel model.

  14. Unconventional dc Transport in Rashba Electron Gases.

    PubMed

    Brosco, Valentina; Benfatto, Lara; Cappelluti, Emmanuele; Grimaldi, Claudio

    2016-04-22

    We discuss the transport properties of a disordered two-dimensional electron gas with strong Rashba spin-orbit coupling. We show that in the high-density regime where the Fermi energy overcomes the energy associated with spin-orbit coupling, dc transport is accurately described by a standard Drude's law, due to a nontrivial compensation between the suppression of backscattering and the relativistic correction to the quasiparticle velocity. On the contrary, when the system enters the opposite dominant spin-orbit regime, Drude's paradigm breaks down and the dc conductivity becomes strongly sensitive to the spin-orbit coupling strength, providing a suitable tool to test the entanglement between spin and charge degrees of freedom in these systems.

  15. 75 FR 38017 - Airworthiness Directives; McDonnell Douglas Corporation Model DC-9-10 Series Airplanes, DC-9-30...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-01

    ... Corporation Model DC- 9-10 Series Airplanes, DC-9-30 Series Airplanes, DC-9-81 (MD-81) Airplanes, DC-9-82 (MD-82) Airplanes, DC-9-83 (MD-83) Airplanes, DC-9- 87 (MD-87) Airplanes, MD-88 Airplanes, and MD-90-30..., Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590. Hand Delivery: U.S. Department...

  16. Engine bleed air reduction in DC-10

    NASA Technical Reports Server (NTRS)

    Newman, W. H.; Viele, M. R.

    1980-01-01

    An 0.8 percent fuel savings was achieved by a reduction in engine bleed air through the use of cabin air recirculation. The recirculation system was evaluated in revenue service on a DC-10. The cabin remained comfortable with reductions in cabin fresh air (engine bleed air) as much as 50 percent. Flight test verified the predicted fuel saving of 0.8 percent.

  17. NASA's DC-8 With Rain Mapping Radar

    NASA Technical Reports Server (NTRS)

    1999-01-01

    In a joint venture between NASA and Japan's NASDA, scientists have been using satellites, airplanes, and boats to measure rain physics in and under thunderstorms over open water. This Quick Time movie shows NASA's DC-8 jet with the instruments like the airborne rain mapping radar, i.e., the Advanced Microwave Precipitation Radiometer (AMPR) and a lightening imaging sensor. Earth science and weather studies are an important ongoing function of NASA and its affiliates.

  18. Static dc voltage stabilizer-converter

    NASA Technical Reports Server (NTRS)

    Osadchiy, V. I.

    1974-01-01

    The advantages are outlined of a static dc voltage converter combining the functions of the feed voltage stabilizer simultaneously. A comparison is made between the circuits for the known static stabilizer converter and that developed by the author. A characteristic feature of the improved system is the increased stabilization coefficient, low output impedance and the possibility of smooth regulation of the output voltage. A practical diagram is presented for the improved high voltage stabilizer converter and its parameters.

  19. Stray current characteristics of DC transit systems

    SciTech Connect

    Moody, K.J. . Transportation Technologies Div.)

    1994-06-01

    The re-emergence and rapid growth of use of DC-powered transit systems around the world has led to the adaptation of three distinct operational modes: grounded, ungrounded, and diode grounded. Each of these modes causes widely varying amounts of stray current in systems using the running rails for negative return current. The advantages of each operational mode and the possible stray current effects on transit and adjacent utility structures are discussed.

  20. DC side filters for multiterminal HVDC systems

    SciTech Connect

    Shore, N.L.; Adamson, K.; Bard, P.

    1996-10-01

    Multiterminal HVDC systems present challenges in the specification and design of suitable dc side filtering. This document examines the existing experience and addresses the particular technical problems posed by multiterminal systems. The filtering requirements of small taps are discussed, as is the potential use of active filters. Aspects of calculation and design are considered and recommendations made to guide the planners and designers of future multiterminal schemes.

  1. DC CHARACTERIZATION OF HIGH GRADIENT MULTILAYER INSULATORS

    SciTech Connect

    Watson, J A; Caporaso, G J; Sampayan, S E; Sanders, D M; Krogh, M L

    2005-05-26

    We have developed a novel insulator concept that involves the use of alternating layers of conductors and insulators with periods less than 1 mm. We have demonstrated that these structures perform 2 to 5 times better than conventional insulators in long pulse, short pulse, and alternating polarity applications. We present new testing results showing exceptional behavior at DC, with gradients in excess of 110kV/cm in vacuum.

  2. Circuit Regulates Speed Of dc Motor

    NASA Technical Reports Server (NTRS)

    Weaver, Charles; Padden, Robin; Brown, Floyd A., Jr.

    1990-01-01

    Driving circuit regulates speed of small dc permanent-magnet motor in tape recorder. Two nested feedback loops maintain speed within 1 percent of constant value. Inner loop provides coarse regulation, while outer loop removes most of variation in speed that remains in the presence of regulation by the inner loop. Compares speed of motor with commanded speed and adjusts current supplied to motor accordingly.

  3. DC-8 Airborne Laboratory in flight

    NASA Technical Reports Server (NTRS)

    1998-01-01

    This 17-second clip shows air-to-air shots of the NASA DC-8 airborne laboratory as it passes over the NASA Dryden Flight Research Center at Edwards, California, and the foothills of the Sierra Nevada mountains. On December 29, 1997, NASA Dryden Flight Research Center, Edwards, California, received a DC-8 airborne laboratory from NASA Ames Research Center, Moffett Field, California, where it had flown missions related to airborne science and earth science for many years. This airplane has continued to be used from Dryden for basic research about the Earth's surface and atmosphere as well as sensor development and satellite sensor verification. In mid-February 1998, the DC-8 resumed flying its medium-altitude, science-gathering missions following maintenance and upgrades of its satellite communications system. It flew a variety of missions over widely scattered geographic regions during the rest of the calendar year and beyond to gather data about earth science, including weather and climate. Built by Douglas Aircraft Company, Long Beach, California, in 1966, the DC-8 flew for 20 years with two major airlines before being acquired by NASA and converted to its present role as an airborne laboratory. The four-engine former jetliner was capable of flying extended-duration missions as long as 12 hours over a range of 5,400 nautical miles at cruise altitudes up to 41,000 feet. It was also capable of carrying a payload of multiple experiments weighing up to 30,000 pounds. On some of its missions, up to 30 scientists have worked on as many as 14 different experiments.

  4. DC-8 airborne laboratory in flight

    NASA Technical Reports Server (NTRS)

    1998-01-01

    In this 26-second clip the NASA DC-8 airborne laboratory is shown making turns over the Sierra Nevada foothills, NASA Dryden Flight Research Center, and Rogers Dry Lakebed at Edwards Air Force Base, California. On December 29, 1997, NASA Dryden Flight Research Center, Edwards, California, received a DC-8 airborne laboratory from NASA Ames Research Center, Moffett Field, California, where it had flown missions related to airborne science and earth science for many years. This airplane has continued to be used from Dryden for basic research about the Earth's surface and atmosphere as well as sensor development and satellite sensor verification. In mid-February 1998, the DC-8 resumed flying its medium-altitude, science-gathering missions following maintenance and upgrades of its satellite communications system. It flew a variety of missions over widely scattered geographic regions during the rest of the calendar year and beyond to gather data about earth science, including weather and climate. Built by Douglas Aircraft Company, Long Beach, California, in 1966, the DC-8 flew for 20 years with two major Airlines before being acquired by NASA and converted to its present role as an airborne laboratory. The four-engine former jetliner was capable of flying extended-duration missions for as long as 12 hours over a range of 5,400 nautical miles at cruise altitudes of up to 41,000 feet. It was also capable of carrying a payload of multiple experiments weighing up to 30,000 pounds. On some of its missions, up to 30 scientists have worked on as many as 14 different experiments.

  5. Performance of 22.4-kW nonlaminated-frame dc series motor with chopper controller. [a dc to dc voltage converter

    NASA Technical Reports Server (NTRS)

    Schwab, J. R.

    1979-01-01

    Performance data obtained through experimental testing of a 22.4 kW traction motor using two types of excitation are presented. Ripple free dc from a motor-generator set for baseline data and pulse width modulated dc as supplied by a battery pack and chopper controller were used for excitation. For the same average values of input voltage and current, the motor power output was independent of the type of excitation. However, at the same speeds, the motor efficiency at low power output (corresponding to low duty cycle of the controller) was 5 to 10 percentage points lower on chopped dc than on ripple free dc. The chopped dc locked-rotor torque was approximately 1 to 3 percent greater than the ripple free dc torque for the same average current.

  6. Estimation of Bidirectional Buck/boost DC/DC Converters with Electric Double-Layer Capacitors for Energy Storage Systems

    NASA Astrophysics Data System (ADS)

    Funabiki, Shigeyuki; Yamamoto, Masayoshi

    Renewable energy such as wind force and solar light has collected the attention as alternative energy sources of fossil fuel. An energy storage system with an electric double-layer capacitor (EDLC), which balances the demand and supply power, is required in order to introduce the electric power generating system that utilizes renewable energy. Currently, the research and development of these energy storage systems are actively carried out. In the energy storage system with an EDLC, the DC/DC converter having the function of the bidirectional power flow and the buck/boost performance is essential as an interface and power control circuit. There are two types of the bidirectional buck/boost DC/DC converters. One type consists of two buck/boost DC/DC converters with one reactor. The other type consists of two sets of two-quadrant DC/DC converters with one reactor. This paper discusses the comparison of these types of DC/DC converters with bidirectional power flow and buck/boost performance. The two types of DC/DC converters are estimated for their application to the energy storage system with the EDLC. As the voltage endurance of the device is lower and the mean current is smaller in the latter type of converter despite of having twice the number of devices compared to the former, the latter type of converter has the advantage of a smaller reactor, i.e., core volume and loss, and lower loss in the converter.

  7. 78 FR 9044 - Adequacy Status of the Motor Vehicle Emission Budgets for Metropolitan Washington DC Area (DC-MD...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-07

    ... From the Federal Register Online via the Government Publishing Office ENVIRONMENTAL PROTECTION AGENCY Adequacy Status of the Motor Vehicle Emission Budgets for Metropolitan Washington DC Area (DC-MD... EPA's finding, the Washington DC-MD-VA Nonattainment Area for the 1997 8-Hour Ozone National...

  8. Development of a smart DC grid model

    NASA Astrophysics Data System (ADS)

    Dalimunthe, Amty Ma'rufah Ardhiyah; Mindara, Jajat Yuda; Panatarani, Camellia; Joni, I. Made

    2016-03-01

    Smart grid and distributed generation should be the solution of the global climate change and the crisis energy of the main source of electrical power generation which is fossil fuel. In order to meet the rising electrical power demand and increasing service quality demands, as well as reduce pollution, the existing power grid infrastructure should be developed into a smart grid and distributed power generation which provide a great opportunity to address issues related to energy efficiency, energy security, power quality and aging infrastructure systems. The conventional of the existing distributed generation system is an AC grid while for a renewable resources requires a DC grid system. This paper explores the model of smart DC grid by introducing a model of smart DC grid with the stable power generation give a minimal and compressed circuitry that can be implemented very cost-effectively with simple components. The PC based application software for controlling was developed to show the condition of the grid and to control the grid become `smart'. The model is then subjected to a severe system perturbation, such as incremental change in loads to test the performance of the system again stability. It is concluded that the system able to detect and controlled the voltage stability which indicating the ability of power system to maintain steady voltage within permissible rangers in normal condition.

  9. Constrained Mathematics for Calculating Logical Safety and Reliability Probabilities with Uncertain Inputs

    SciTech Connect

    Cooper, D.K.; Cooper, J.A.; Ferson, S.

    1999-01-21

    Calculating safety and reliability probabilities with functions of uncertain variables can yield incorrect or misleading results if some precautions are not taken. One important consideration is the application of constrained mathematics for calculating probabilities for functions that contain repeated variables. This paper includes a description of the problem and develops a methodology for obtaining an accurate solution.

  10. Holistic Integrated Design Education: Art Education in a Complex and Uncertain World

    ERIC Educational Resources Information Center

    Nokes, Christopher

    2005-01-01

    Learning, which is understood as a change in behavior, is a process of becoming. This monograph introduces the neologism egosystem as an amalgam of the individual, the self and its attendant ego, and socio-environmental schemata swirling around the individual. In an uncertain and probabilistic universe, the role of chaos theory in recognizing…

  11. Fuzzy Stochastic Petri Nets for Modeling Biological Systems with Uncertain Kinetic Parameters

    PubMed Central

    Liu, Fei; Heiner, Monika; Yang, Ming

    2016-01-01

    Stochastic Petri nets (SPNs) have been widely used to model randomness which is an inherent feature of biological systems. However, for many biological systems, some kinetic parameters may be uncertain due to incomplete, vague or missing kinetic data (often called fuzzy uncertainty), or naturally vary, e.g., between different individuals, experimental conditions, etc. (often called variability), which has prevented a wider application of SPNs that require accurate parameters. Considering the strength of fuzzy sets to deal with uncertain information, we apply a specific type of stochastic Petri nets, fuzzy stochastic Petri nets (FSPNs), to model and analyze biological systems with uncertain kinetic parameters. FSPNs combine SPNs and fuzzy sets, thereby taking into account both randomness and fuzziness of biological systems. For a biological system, SPNs model the randomness, while fuzzy sets model kinetic parameters with fuzzy uncertainty or variability by associating each parameter with a fuzzy number instead of a crisp real value. We introduce a simulation-based analysis method for FSPNs to explore the uncertainties of outputs resulting from the uncertainties associated with input parameters, which works equally well for bounded and unbounded models. We illustrate our approach using a yeast polarization model having an infinite state space, which shows the appropriateness of FSPNs in combination with simulation-based analysis for modeling and analyzing biological systems with uncertain information. PMID:26910830

  12. Feature-Based versus Category-Based Induction with Uncertain Categories

    ERIC Educational Resources Information Center

    Griffiths, Oren; Hayes, Brett K.; Newell, Ben R.

    2012-01-01

    Previous research has suggested that when feature inferences have to be made about an instance whose category membership is uncertain, feature-based inductive reasoning is used to the exclusion of category-based induction. These results contrast with the observation that people can and do use category-based induction when category membership is…

  13. Controllable uncertain opinion diffusion under confidence bound and unpredicted diffusion probability

    NASA Astrophysics Data System (ADS)

    Yan, Fuhan; Li, Zhaofeng; Jiang, Yichuan

    2016-05-01

    The issues of modeling and analyzing diffusion in social networks have been extensively studied in the last few decades. Recently, many studies focus on uncertain diffusion process. The uncertainty of diffusion process means that the diffusion probability is unpredicted because of some complex factors. For instance, the variety of individuals' opinions is an important factor that can cause uncertainty of diffusion probability. In detail, the difference between opinions can influence the diffusion probability, and then the evolution of opinions will cause the uncertainty of diffusion probability. It is known that controlling the diffusion process is important in the context of viral marketing and political propaganda. However, previous methods are hardly feasible to control the uncertain diffusion process of individual opinion. In this paper, we present suitable strategy to control this diffusion process based on the approximate estimation of the uncertain factors. We formulate a model in which the diffusion probability is influenced by the distance between opinions, and briefly discuss the properties of the diffusion model. Then, we present an optimization problem at the background of voting to show how to control this uncertain diffusion process. In detail, it is assumed that each individual can choose one of the two candidates or abstention based on his/her opinion. Then, we present strategy to set suitable initiators and their opinions so that the advantage of one candidate will be maximized at the end of diffusion. The results show that traditional influence maximization algorithms are not applicable to this problem, and our algorithm can achieve expected performance.

  14. Urban School Finance: Increased Standards and Accountability in Uncertain Economic Times.

    ERIC Educational Resources Information Center

    Rice, Jennifer King; Roellke, Christopher

    2003-01-01

    Discusses issues related to the funding of urban schools during uncertain economic periods. Includes the complexity of urban school reform, teacher supply and quality in urban schools, nontraditional support for urban schools, and markets and accountability in urban schools. (Contains 36 references.) (PKP)

  15. Hybrid state-space self-tuning control of uncertain linear systems

    NASA Technical Reports Server (NTRS)

    Shieh, L. S.; Wang, Y. J.; Sunkel, J. W.

    1993-01-01

    The paper presents a hybrid state-space self-tuner using a new dual-rate sampling scheme for digital adaptive control of continuous-time uncertain linear systems. A state-space-based recursive least-squares algorithm, together with a variable forgetting factor, is used for direct estimations of both the equivalent discrete-time uncertain linear system parameters and the associated discrete-time state of a continuous-time uncertain linear system from the sampled input and output data. An analogue optimal regional pole-placement design method is used for designing an optimal observer-based analogue controller. A suboptimal observer-based digital controller is then designed from the designed analogue controller using digital redesign technique. To enhance the robustness of parameter identification and state estimation algorithms, a dynamic bound for a class of uncertain bilinear parameters and a fast-rate digital controller are developed at each fast-sampling period. Also, to accommodate computation loads and computation delay for developing the advanced hybrid self-tuner, the designed analogue controller and observer gains are both updated at each slow-sampling period. This control technique has been successfully applied to benchmark control problems.

  16. Fuzzy Stochastic Petri Nets for Modeling Biological Systems with Uncertain Kinetic Parameters.

    PubMed

    Liu, Fei; Heiner, Monika; Yang, Ming

    2016-01-01

    Stochastic Petri nets (SPNs) have been widely used to model randomness which is an inherent feature of biological systems. However, for many biological systems, some kinetic parameters may be uncertain due to incomplete, vague or missing kinetic data (often called fuzzy uncertainty), or naturally vary, e.g., between different individuals, experimental conditions, etc. (often called variability), which has prevented a wider application of SPNs that require accurate parameters. Considering the strength of fuzzy sets to deal with uncertain information, we apply a specific type of stochastic Petri nets, fuzzy stochastic Petri nets (FSPNs), to model and analyze biological systems with uncertain kinetic parameters. FSPNs combine SPNs and fuzzy sets, thereby taking into account both randomness and fuzziness of biological systems. For a biological system, SPNs model the randomness, while fuzzy sets model kinetic parameters with fuzzy uncertainty or variability by associating each parameter with a fuzzy number instead of a crisp real value. We introduce a simulation-based analysis method for FSPNs to explore the uncertainties of outputs resulting from the uncertainties associated with input parameters, which works equally well for bounded and unbounded models. We illustrate our approach using a yeast polarization model having an infinite state space, which shows the appropriateness of FSPNs in combination with simulation-based analysis for modeling and analyzing biological systems with uncertain information.

  17. An Exemplar-Model Account of Feature Inference from Uncertain Categorizations

    ERIC Educational Resources Information Center

    Nosofsky, Robert M.

    2015-01-01

    In a highly systematic literature, researchers have investigated the manner in which people make feature inferences in paradigms involving uncertain categorizations (e.g., Griffiths, Hayes, & Newell, 2012; Murphy & Ross, 1994, 2007, 2010a). Although researchers have discussed the implications of the results for models of categorization and…

  18. Scenarios for the Future of Air Quality: Planning and Analysis in an Uncertain World

    EPA Science Inventory

    On November 15 and 16 of 2010, EPA hosted a workshop: The Future of Air Quality: Planning and Analysis in An Uncertain World in Chapel Hill, North Carolina. This workshop was an “outside-of-the-box” thinking exercise, where a small group of EPA staff and managers brainstormed o...

  19. Why Weepest Thou so Sore? When a Mother's Pathway Is Fragile and Uncertain

    ERIC Educational Resources Information Center

    Ostler, Teresa

    2012-01-01

    When a mother has a severe and chronic mental illness, her pathway ahead as a parent can be fragile and uncertain. This article describes a therapeutic support group for women with mental illness and reveals how individual women responded to a group that was created to support them in the parenting role. Periods of silence followed by palpable…

  20. Application of dynamic uncertain causality graph in spacecraft fault diagnosis: Multi-conditions

    NASA Astrophysics Data System (ADS)

    Yao, Quanying; Zhang, Qin; Liu, Peng; Yang, Ping; Wang, Xiaochen; Zhu, Ma

    2017-03-01

    Intelligent diagnosis system is applied to fault diagnosis in spacecraft. Dynamic Uncertain Causality Graph (DUCG) is a new probability graphic model with many advantages. In this paper, DUGG is applied to fault diagnosis in spacecraft: introducing conditional functional events into ordinary DUCG to deal with spacecraft multi-conditions. Now, DUCG has been tested in 16 typical faults with 100% diagnosis accuracy.

  1. Ga-67 positivity in sarcoidosis of the skin with coincident thyroid uptake of uncertain etiology

    SciTech Connect

    Moreno, A.J.; Brown, J.M.; Salinas, J.A.; Feaster, B.L.; Brown, T.J.

    1984-03-01

    Gallium-67 citrate scintigraphy of a 26-year-old woman with systemic sarcoidosis demonstrated abnormal radiotracer uptake within multiple biopsy-proven sarcoidal cutaneous lesions and within both lobes of the thyroid gland. The etiology of the thyroidal uptake of the Ga-67 was uncertain but it may represent sarcoidal involvement of the gland.

  2. Older Children's Misunderstanding of Uncertain Belief after Passing the False Belief Test

    ERIC Educational Resources Information Center

    Zhang, Ting; Zheng, Xueru; Zhang, Li; Sha, Wenju; Deak, Gedeon; Li, Hong

    2010-01-01

    A four-location belief task was designed to examine children's understanding of another's uncertain belief after passing a false belief (FB) task. In Experiment 1, after passing the FB task, participants were asked what a puppet would do after he failed to find his toy at the falsely believed location. Most 4-year-olds and half of 6-year-olds…

  3. The Bone in the Throat: Some Uncertain Thoughts on Baroque Method

    ERIC Educational Resources Information Center

    MacLure, Maggie

    2006-01-01

    The paper conjures some possibilities for a baroque method in qualitative educational research. It draws on work across a range of disciplines that has detected a recurrence of the baroque in the philosophical and literary texts of modernity. A baroque method would resist clarity, mastery and the single point of view, be radically uncertain about…

  4. Stress-Induced Accumulation of DcAOX1 and DcAOX2a Transcripts Coincides with Critical Time Point for Structural Biomass Prediction in Carrot Primary Cultures (Daucus carota L.)

    PubMed Central

    Campos, M. Doroteia; Nogales, Amaia; Cardoso, Hélia G.; Kumar, Sarma R.; Nobre, Tânia; Sathishkumar, Ramalingam; Arnholdt-Schmitt, Birgit

    2016-01-01

    Stress-adaptive cell plasticity in target tissues and cells for plant biomass growth is important for yield stability. In vitro systems with reproducible cell plasticity can help to identify relevant metabolic and molecular events during early cell reprogramming. In carrot, regulation of the central root meristem is a critical target for yield-determining secondary growth. Calorespirometry, a tool previously identified as promising for predictive growth phenotyping has been applied to measure the respiration rate in carrot meristem. In a carrot primary culture system (PCS), this tool allowed identifying an early peak related with structural biomass formation during lag phase of growth, around the 4th day of culture. In the present study, we report a dynamic and correlated expression of carrot AOX genes (DcAOX1 and DcAOX2a) during PCS lag phase and during exponential growth. Both genes showed an increase in transcript levels until 36 h after explant inoculation, and a subsequent down-regulation, before the initiation of exponential growth. In PCS growing at two different temperatures (21°C and 28°C), DcAOX1 was also found to be more expressed in the highest temperature. DcAOX genes’ were further explored in a plant pot experiment in response to chilling, which confirmed the early AOX transcript increase prior to the induction of a specific anti-freezing gene. Our findings point to DcAOX1 and DcAOX2a as being reasonable candidates for functional marker development related to early cell reprogramming. While the genomic sequence of DcAOX2a was previously described, we characterize here the complete genomic sequence of DcAOX1. PMID:26858746

  5. CD8α¯ DC is the major DC subset which mediates inhibition of allergic responses by Schistosoma infection.

    PubMed

    Liu, J-Y; Lu, P; Hu, L-Z; Shen, Y-J; Zhu, Y-J; Ren, J-L; Ji, W-H; Zhang, X-Z; Wu, Z-Q; Yang, X-Z; Yang, J; Li, L-Y; Yang, X; Liu, P-M

    2014-12-01

    Our and others' previous studies have shown that Schistosoma japonicum (SJ) infection can inhibit allergic reactions. We recently reported that DCs played an important role in SJ infection-mediated inhibition of allergy, which was associated with enhanced IL-10 and T regulatory cell responses. Here, we further compared the role of CD8α(+) DC and CD8α(-) DC subsets for the inhibitory effect. We sorted CD8α(+) DC (SJCD8α(+) DC) and CD8α(-) DC (SJCD8α(-) DC) from SJ-infected mice and tested their ability to modulate allergic responses in vivo. The data showed that the adoptive transfer of SJCD8α(-) DC was much more efficient than SJCD8α(+) DC for the suppression of allergic airway eosinophilia, mucus overproduction, antigen-specific IgE responses, and Th2 cytokines (IL-4 and IL-5). More importantly, we found that the transfer of SJCD8α(-) DC, but not SJCD8α(+) DC, significantly increased IL-10 and TGF-β production following OVA exposure. As control, the transfer of DC subsets from naïve mice had no significant effect on allergic inflammation. In addition, SJCD8α-DC expressed significantly higher IL-10 but lower IL-12, CD80 and CD86 than SJCD8α(+) DC, fitting a tolerogenic phenotype. The results suggest that CD8α(-) DC is the predominant DC subset which is involved in the parasitic infection-mediated inhibition of allergic inflammation and possibly through enhancing immunomodulatory cytokine (IL-10 and TGF-β) production.

  6. Exploring Alternative Conceptions from Newtonian Dynamics and Simple DC Circuits: Links between Item Difficulty and Item Confidence

    ERIC Educational Resources Information Center

    Planinic, Maja; Boone, William J.; Krsnik, Rudolf; Beilfuss, Meredith L.

    2006-01-01

    Croatian 1st-year and 3rd-year high-school students (N = 170) completed a conceptual physics test. Students were evaluated with regard to two physics topics: Newtonian dynamics and simple DC circuits. Students answered test items and also indicated their confidence in each answer. Rasch analysis facilitated the calculation of three linear…

  7. Different functions and associations of HLA-DR and HLA-DQ(DC) antigens shown by serological, cellular and DNA assays.

    PubMed

    Navarrete, C; Jaraquemada, D; Hui, K; Awad, J; Okoye, R; Festenstein, H

    1985-03-01

    Two consanguineous Caucasoid HTCs, DHI and FPA, were investigated, the latter having an unusual HLA-DR/DQ(DC) association. Both these HTCs typed clearly as HLA-DRw11. However, while DHI typed as DRw11/DQw3(DC4) as expected, FPA typed as DRw11/DQw1(DC1) instead. Although extremely rare in Caucasoids, DRw11/DQw1 is a common pattern of association in Nigerian Negroids. Southern blots of DNA extracted from EBV cell line derived from FPA, hybridized with HLA-DC alpha and HLA-DC beta probes, confirmed this unusual DRw11/DQw1(DC1) association. In addition the DC alpha probe showed a unique additional restriction fragment length polymorphism (8 kb) attributable to the DX gene in the FPA DNA. When DHI and FPA were used as stimulators in MLC, the patterns to typing responses obtained were not completely concordant although they overlap to some extent. For this reason FPA has been locally designated Dw'F5', distinct from Dw5. Furthermore, the HLA-DQ antigens of the responder cells were not necessarily the same as those of the HTCS to which they gave typing responses (FPA and DHI). Functional studies using these two HTCs showed that the DQ(DC) antigens probably have no direct lymphocyte activating properties but rather have a regulatory role in controlling responses to allodeterminants in MLC.

  8. New topology for DC/DC bidirectional converter for hybrid systems in renewable energy

    NASA Astrophysics Data System (ADS)

    Lopez, Juan Carlos; Ortega, Manuel; Jurado, Francisco

    2015-03-01

    This article presents a new isolated DC/DC bidirectional converter with soft switching, using a transformer with two voltage taps and two full bridges with insulated-gate bipolar transistors (IGBTs), one on each side of the transformer to be integrated in hybrid systems of renewable energy. A large voltage conversion ratio can be achieved using this converter, in buck and booster modes. Also medium and high DC power can be converted with a good efficiency. Analysis and switching techniques have been reported. To verify the principle of operation, a laboratory prototype of 10 kW has been performed. Experimental results are presented, operating in boost mode. The switching algorithm used has been modelled in MATLAB-Simulink to generate C code. This code has been implemented in a DSP F2812, which has been used to build the prototype.

  9. Some results regarding stability of photovoltaic maximum-power-point tracking dc-dc converters

    NASA Astrophysics Data System (ADS)

    Schaefer, John F.

    An analytical investigation of a class of photovoltaic (PV) maximum-power-point tracking dc-dc converters has yielded basic results relative to the stability of such devices. Necessary and sufficient conditions for stable operation are derived, and design tools are given. Specific results have been obtained for arbitrary PV arrays driving converters powering resistive loads and batteries. The analytical techniques are applicable to inverters, also. Portions of the theoretical results have been verified in operational devices: a 1500 watt unit has driven a 1-horsepower, 90-volt dc motor powering a water pump jack for over one year. Prior to modification shortly after initial installation, the unit exhibited instability at low levels of irradiance, as predicted by the theory. Two examples are provided.

  10. 75 FR 82333 - Airworthiness Directives; McDonnell Douglas Corporation Model DC-10-10, DC-10-10F, and MD-10-10F...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-30

    ... Corporation Model DC- 10-10, DC-10-10F, and MD-10-10F Airplanes AGENCY: Federal Aviation Administration (FAA... directive (AD) for certain Model DC-10-10, DC-10-10F, and MD-10-10F airplanes. This proposed AD would...., Washington, DC 20590. Hand Delivery: U.S. Department of Transportation, Docket Operations, M-30,...

  11. DC-to-dc converter power-train optimization for maximum efficiency

    NASA Astrophysics Data System (ADS)

    Wilson, T. G., Jr.; Whelan, E. W., Jr.; Rodriguez, R.; Dishman, J. M.

    This paper presents a new way of describing the independent and dependent design variables of the power train of a dc-to-dc converter in terms of a multi-dimensional design-parameter space. These concepts provide a framework for examining the problem of design optimization of the power train, with particular emphasis on the maximization of converter efficiency. Numerous examples of important parameter-space surfaces illustrate some of the major relationships between core volume, switching frequency and output power, and between efficiency, ripple, and temperature rise of the energy-storage reactor. Also, we explore the difference in performance between the continuous and discontinuous mmf modes of operation.

  12. Soft-start mechanism with coefficients Ki optimization for DC-DC power converters

    NASA Astrophysics Data System (ADS)

    Wang, Qian; Hu, Jiajun; Chen, Houpeng; Li, Xi; Fan, Xi; Miao, Jie; Song, Zhitang

    2016-10-01

    This paper presents a fully digital-control soft start mechanism with coefficients Ki optimization for DC-DC power converters. During the soft start phase, a ladder reference voltage steps up gradually to make inductor current ramp up smoothly and overshoot voltage is minimized with the proposed coefficients Ki distribution. Simulation results show that massive inductor current can be well avoided during the soft start process with the proposed soft start mechanism, which only occupies a chip area of 300um×120um.

  13. A High Power Density DC-DC Converter for Distributed PV Architectures

    SciTech Connect

    Agamy, Mohammed S; Chi, Song; Elasser, Ahmed; Harfman-Todorovic, Maja; Jiang, Yan; Mueller, Frank; Tao, Fengfeng

    2012-06-01

    In order to maximize solar energy harvesting capabilities, power converters have to be designed for high efficiency and good MPPT and voltage/current performance. When many converters are used in distributed systems, power density also becomes an important factor as it allows for simpler system integration. In this paper a high power density string dc-dc converter suitable for distributed medium to large scale PV installation is presented. A simple partial power processing topology, implemented with all silicon carbide devices provides high efficiency as well as high power density. A 3.5kW, 100kHz converter is designed and tested to verify the proposed methods.

  14. A New Approach for High Efficiency Buck-Boost DC/DC Converters Using Series Compensation

    NASA Astrophysics Data System (ADS)

    Itoh, Jun-Ichi; Fujii, Takashi

    This paper proposes a novel concept for non-isolated buck-boost DC/DC converter and control method. The proposed concept uses a series connection converter that only regulates the differential voltage between the input and output voltage. As a result, the power converter capacity is decreased. Moreover, the proposed circuit has advantages such as improved efficiency and losses reduction. The fundamental operation, control method, and design method of the proposed circuit are described in this paper. In addition, the validity of the proposed circuit is confirmed by carrying out simulations and experiments.

  15. Real-Time Implementation of a Fuzzy Logic Controller for DC-DC Switching Converters

    DTIC Science & Technology

    2007-11-02

    studies, it will be observed that, the proposed fuzzy controller maintains the output voltage at the desired 5V with slight overshoot during each...537-546, May 1997. [3] H. Sira -Ramirez, “Design of P-I controllers for DC-to-DC power supplies via extended linearization,” Int. J. Control, vol. 51...Technology, vol. 7, pp. 230-237, Mar. 1999. [5] G. Escobar, R. Ortega, H. Sira -Ramirez, J.P. Vilain and I. Zein, “An experimental comparison of several

  16. DC-DC Converter Topology Assessment for Large Scale Distributed Photovoltaic Plant Architectures

    SciTech Connect

    Agamy, Mohammed S; Harfman-Todorovic, Maja; Elasser, Ahmed; Sabate, Juan A; Steigerwald, Robert L; Jiang, Yan; Essakiappan, Somasundaram

    2011-07-01

    Distributed photovoltaic (PV) plant architectures are emerging as a replacement for the classical central inverter based systems. However, power converters of smaller ratings may have a negative impact on system efficiency, reliability and cost. Therefore, it is necessary to design converters with very high efficiency and simpler topologies in order not to offset the benefits gained by using distributed PV systems. In this paper an evaluation of the selection criteria for dc-dc converters for distributed PV systems is performed; this evaluation includes efficiency, simplicity of design, reliability and cost. Based on this evaluation, recommendations can be made as to which class of converters is best fit for this application.

  17. CMOS-Compatible SOI MESFETS for Radiation-Hardened DC-to-DC Converters

    NASA Technical Reports Server (NTRS)

    Thornton, Trevor; Lepkowski, William; Wilk, Seth

    2013-01-01

    A radiation-tolerant transistor switch has been developed that can operate between 196 and +150 C for DC-to-DC power conversion applications. A prototype buck regulator component was demonstrated to be performing well after a total ionizing dose of 300 krad(Si). The prototype buck converters showed good efficiencies at ultra-high switching speeds in the range of 1 to 10 MHz. Such high switching frequency will enable smaller, lighter buck converters to be developed as part of the next project. Switching regulators are widely used in commercial applications including portable consumer electronics.

  18. Research on transient hysteresis current control strategy of DC-DC converter

    NASA Astrophysics Data System (ADS)

    Zhang, Ting; Wang, Zu-liang; Zhao, Yu-kai

    2017-01-01

    In order to improve the dynamic performance of DC-DC converter, transient hysteresis current control strategy is proposed which is based on parallel computing and combinational logic. By making a comparison between the real-time inductor current and the threshold inductor current, the switch is controlled more accurately. Under the Matlab/Simulink environment, the process of the Buck-Boost converter was simulated. The simulation results show that the transient hysteresis current control strategy can effectively overcome the disadvantages when load changes or input voltage disturbance occurs, it posses high load regulation and short dynamic response time, and it verifies the feasibility of the proposed strategy.

  19. 77 FR 46118 - Notice of Inventory Completion: Department of the Interior, Bureau of Indian Affairs, Washington...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-02

    ..., Washington, DC, and Logan Museum of Anthropology, Beloit College, Beloit, WI AGENCY: National Park Service... Museum of Anthropology, Beloit College, have completed an inventory of human remains, in consultation... Museum of Anthropology, Beloit College, Beloit, WI. The human remains were removed from an...

  20. Improved DC Gun and Insulator Assembly

    SciTech Connect

    Neubauer, Michael

    2015-01-11

    Many user facilities such as synchrotron radiation light sources and free electron lasers rely on DC high voltage photoguns with internal field gradients as high as 10 to 15 MV/m. These high gradients often lead to field emission which poses serious problems for the photocathode used to generate the electron beam and the ceramic insulators used to bias the photocathode at high voltage. Ceramic insulators are difficult to manufacture, require long commissioning times, and have poor reliability, in part because energetic electrons bury themselves in the ceramic causing a buildup of charge and eventual puncture, and also because large diameter ceramics are difficult to braze reliably. The lifetimes of photo cathodes inside high current DC guns exhibiting field emission are limited to less than a hundred hours. Reducing the surface gradients on the metals reduces the field emission, which serves to maintain the required ultrahigh vacuum condition. A novel gun design with gradients around 5 MV/m and operating at 350 kV, a major improvement over existing designs, was proposed that allows for the in-situ replacement of photo cathodes in axially symmetric designs using inverted ceramics. In this project, the existing JLAB CEBAF asymmetric gun design with an inverted ceramic support was modeled and the beam dynamics characterized. An improved structure was designed that reduces the surface gradients and improves the beam optics. To minimize the surface gradients, a number of electrostatic gun designs were studied to determine the optimum configuration of the critical electrodes within the gun structure. Coating experiments were carried out to create a charge dissipative coating for cylindrical ceramics. The phase II proposal, which was not granted, included the design and fabrication of an axially symmetric DC Gun with an inverted ceramic that would operate with less than 5 MV/m at 350 kV and would be designed with an in-situ replaceable photo-cathode.

  1. Two-position dc pulse voltage stabilizer

    NASA Technical Reports Server (NTRS)

    Osadchiy, V. I.

    1974-01-01

    The advantages of the dc pulse voltage stabilizers over the continuous action stabilizers are described. These advantages include higher efficiency, low sensitivity to the ambient temperature and insignificant size and weight. A comparison is made between the schematics of the known two position pulse stabilizer with a Schmitt trigger and that developed by the author. A characteristic feature of the improved system is the increased stabilization coefficient and the possibility of smooth regulation of the output voltage. A practical schematic is presented for the improved two position pulse stabilizer along with its parameters.

  2. CVD diamond growth by dc plasma torch

    NASA Astrophysics Data System (ADS)

    Klocek, Paul; Hoggins, James T.; Taborek, Peter; McKenna, Tom A.

    1990-12-01

    A dc arc discharge plasma torch has been developed for chemical vapor deposition (CVD) diamond growth. The apparatus and process parameters are described. Free-standing polycrystalline diamond samples of 50 mm by 50 mm by a few mm have been grown at high rates. The Raman spectra of the samples show little nondiamond structure. Transmission electron microscopy indicates that the diamond is highly twinned and has a high defect concentration. The infrared spectra indicate the presence of hydrogen contamination in the diamond via absorption bands associated with carbon-hydrogen motion. 2.

  3. Fun D.C. Jobs for Physicists

    SciTech Connect

    Clark Cully

    2009-09-30

    Physicists make valuable contributions in a wide variety of careers, including those in Washington. Many national challenges, including energy, innovation, and security, create a demand for technically-competent individuals across government. Clark will discuss some of the many programs in D.C. designed to attract the best and brightest minds, from grad-students to professors, from short-term assignments to whole new careers. These are great opportunities to use your expertise and enrich your knowledge of the broader scientific enterprise, all while serving society.

  4. Modelling of dc characteristics for granular semiconductors

    NASA Astrophysics Data System (ADS)

    Varpula, Aapo; Sinkkonen, Juha; Novikov, Sergey

    2010-11-01

    The dc characteristics of granular n-type semiconductors are calculated analytically with the drift-diffusion theory. Electronic trapping at the grain boundaries (GBs) is taken into account. The use of quadratic and linear GB potential profiles in the calculation is compared. The analytical model is verified with numerical simulation performed by SILVACO ATLAS. The agreement between the analytical and numerical results is excellent in a large voltage range. The results show that electronic trapping at the GBs has a remarkable effect on the highly nonlinear I-V characteristics of the material.

  5. Preparing to pass the DC test.

    PubMed

    Rogers, A

    Andrew Rogers discusses the high anxiety levels and high failure rates among those sitting the DC test for entry into nurse education. He goes on to describe a preparatory course developed at one school of nursing which aims to provide an early opportunity for candidates to discuss issues relating to nurse training. A mock test allows individuals to receive guidance on their exam performance and to lessen the degree of anxiety which the test itself can generate. Success rates rose among those who followed the preparatory course.

  6. Tunable graphene dc superconducting quantum interference device.

    PubMed

    Girit, Caglar; Bouchiat, V; Naaman, O; Zhang, Y; Crommie, M F; Zettl, A; Siddiqi, I

    2009-01-01

    Graphene exhibits unique electrical properties on account of its reduced dimensionality and "relativistic" band structure. When contacted with two superconducting electrodes, graphene can support Cooper pair transport, resulting in the well-known Josephson effect. We report here the fabrication and operation of a two junction dc superconducting quantum interference device (SQUID) formed by a single graphene sheet contacted with aluminum/palladium electrodes in the geometry of a loop. The supercurrent in this device can be modulated not only via an electrostatic gate but also by an applied magnetic fielda potentially powerful probe of electronic transport in graphene and an ultrasensitive platform for nanomagnetometry.

  7. A dc Penning Surface-Plasma Source

    DTIC Science & Technology

    2007-11-02

    LA-UR-93-2990 Title: A dc Penning Surface-Plasma Source Author(s): Submitted to: H. Vernon Smith, Jr., Paul Allison, Carl Geisik, David R...Type: HC Number of Copies In Library: 000001 Record ID: 28620 A de Penning Surface-Plasma Source* H. Vernon Smith, Jr., Paul Allison, Carl Geisik...Schechter, J. H. Whealton, and J. J. Donaghy, ATP Conf. Proc. No. 158, 366 (1987). 8) H. V. Smith, Jr., N. M. Schnurr, D. H. Whitaker , and K. E. Kalash

  8. Classification of electrical discharges in DC Accelerators

    NASA Astrophysics Data System (ADS)

    Banerjee, Srutarshi; Deb, A. K.; Rajan, Rehim N.; Kishore, N. K.

    2016-08-01

    Controlled electrical discharge aids in conditioning of the system while uncontrolled discharges damage its electronic components. DC Accelerator being a high voltage system is no exception. It is useful to classify electrical discharges according to the severity. Experimental prototypes of the accelerator discharges are developed. Photomultiplier Tubes (PMTs) are used to detect the signals from these discharges. Time and Frequency domain characteristics of the detected discharges are used to extract features. Machine Learning approaches like Fuzzy Logic, Neural Network and Least Squares Support Vector Machine (LSSVM) are employed to classify the discharges. This aids in detecting the severity of the discharges.

  9. Development of a photo-voltaic pumping system using a brushless D.C. motor and helical rotor pump

    SciTech Connect

    Langridge, D.; Lawrance, W.; Wichert, B.

    1996-12-31

    A PV pumping system based on a brushless d.c. motor and helical rotor pump has been designed, simulated and a prototype constructed. The paper describes the operation of the system and the development of component models for the array, the brushless d.c. motor and helical rotor pump. Simulation results and subsequent test results for the complete system are included. Efficiencies of between 30 and 50% for the system (excluding the array) have been achieved over a range of loads and operating conditions for 4 x 1 and 4 x 2 array configurations. 9 refs., 10 figs., 2 tabs.

  10. Distinct usage of three C-type lectins by Japanese encephalitis virus: DC-SIGN, DC-SIGNR, and LSECtin.

    PubMed

    Shimojima, Masayuki; Takenouchi, Atsushi; Shimoda, Hiroshi; Kimura, Naho; Maeda, Ken

    2014-08-01

    Infection with West Nile virus and dengue virus, two mosquito-borne flaviviruses, is enhanced by two calcium-dependent lectins: dendritic cell-specific intercellular adhesion molecule-3-grabbing nonintegrin (DC-SIGN), and its related molecule (DC-SIGNR). The present study examined the relationship between Japanese encephalitis virus (JEV) infection and three lectins: DC-SIGN, DC-SIGNR, and liver sinusoidal endothelial cell lectin (LSECtin). Expression of DC-SIGNR resulted in robust JEV proliferation in a lymphoid cell line, Daudi cells, which was otherwise non-permissive to infection. DC-SIGN expression caused moderate JEV proliferation, with effects that varied according to the cells in which JEV was prepared. LSECtin expression had comparatively minor, but consistent, effects, in all cell types used in JEV preparation. While DC-SIGN/DC-SIGNR-mediated JEV infection was inhibited by yeast mannan, LSECtin-mediated infection was inhibited by N-acetylglucosamine β1-2 mannose. Although involvement of DC-SIGN/DC-SIGNR in infection seems to be a common characteristic, this is the first report on usage of LSECtin in mosquito-borne flavivirus infection.

  11. A robust model predictive control algorithm for uncertain nonlinear systems that guarantees resolvability

    NASA Technical Reports Server (NTRS)

    Acikmese, Ahmet Behcet; Carson, John M., III

    2006-01-01

    A robustly stabilizing MPC (model predictive control) algorithm for uncertain nonlinear systems is developed that guarantees resolvability. With resolvability, initial feasibility of the finite-horizon optimal control problem implies future feasibility in a receding-horizon framework. The control consists of two components; (i) feed-forward, and (ii) feedback part. Feed-forward control is obtained by online solution of a finite-horizon optimal control problem for the nominal system dynamics. The feedback control policy is designed off-line based on a bound on the uncertainty in the system model. The entire controller is shown to be robustly stabilizing with a region of attraction composed of initial states for which the finite-horizon optimal control problem is feasible. The controller design for this algorithm is demonstrated on a class of systems with uncertain nonlinear terms that have norm-bounded derivatives and derivatives in polytopes. An illustrative numerical example is also provided.

  12. Broadening the study of inductive reasoning: confirmation judgments with uncertain evidence.

    PubMed

    Mastropasqua, Tommaso; Crupi, Vincenzo; Tentori, Katya

    2010-10-01

    Although evidence in real life is often uncertain, the psychology of inductive reasoning has, so far, been confined to certain evidence. The present study extends previous research by investigating whether people properly estimate the impact of uncertain evidence on a given hypothesis. Two experiments are reported, in which the uncertainty of evidence is explicitly (by means of numerical values) versus implicitly (by means of ambiguous pictures) manipulated. The results show that people's judgments are highly correlated with those predicted by normatively sound Bayesian measures of impact. This sensitivity to the degree of evidential uncertainty supports the centrality of inductive reasoning in cognition and opens the path to the study of this issue in more naturalistic settings.

  13. Stabilization of a Quadrotor With Uncertain Suspended Load Using Sliding Mode Control

    SciTech Connect

    Zhou, Xu; Liu, Rui; Zhang, Jiucai; Zhang, Xiaoli

    2016-08-21

    The stability and trajectory control of a quadrotor carrying a suspended load with a fixed known mass has been extensively studied in recent years. However, the load mass is not always known beforehand in practical applications. This mass uncertainty brings uncertain disturbances to the quadrotor system, causing existing controllers to have a worse performance or to be collapsed. To improve the quadrotor's stability in this situation, we investigate the impacts of the uncertain load mass on the quadrotor. By comparing the simulation results of two controllers -- the proportional-derivative (PD) controller and the sliding mode controller (SMC) driven by a sliding mode disturbance of observer (SMDO), the quadrotor's performance is verified to be worse as the uncertainty increases. The simulation results also show a controller with stronger robustness against disturbances is better for practical applications.

  14. Secure estimation, control and optimization of uncertain cyber-physical systems with applications to power networks

    NASA Astrophysics Data System (ADS)

    Taha, Ahmad Fayez

    Transportation networks, wearable devices, energy systems, and the book you are reading now are all ubiquitous cyber-physical systems (CPS). These inherently uncertain systems combine physical phenomena with communication, data processing, control and optimization. Many CPSs are controlled and monitored by real-time control systems that use communication networks to transmit and receive data from systems modeled by physical processes. Existing studies have addressed a breadth of challenges related to the design of CPSs. However, there is a lack of studies on uncertain CPSs subject to dynamic unknown inputs and cyber-attacks---an artifact of the insertion of communication networks and the growing complexity of CPSs. The objective of this dissertation is to create secure, computational foundations for uncertain CPSs by establishing a framework to control, estimate and optimize the operation of these systems. With major emphasis on power networks, the dissertation deals with the design of secure computational methods for uncertain CPSs, focusing on three crucial issues---(1) cyber-security and risk-mitigation, (2) network-induced time-delays and perturbations and (3) the encompassed extreme time-scales. The dissertation consists of four parts. In the first part, we investigate dynamic state estimation (DSE) methods and rigorously examine the strengths and weaknesses of the proposed routines under dynamic attack-vectors and unknown inputs. In the second part, and utilizing high-frequency measurements in smart grids and the developed DSE methods in the first part, we present a risk mitigation strategy that minimizes the encountered threat levels, while ensuring the continual observability of the system through available, safe measurements. The developed methods in the first two parts rely on the assumption that the uncertain CPS is not experiencing time-delays, an assumption that might fail under certain conditions. To overcome this challenge, networked unknown input

  15. Multiobjective optimization in structural design with uncertain parameters and stochastic processes

    NASA Technical Reports Server (NTRS)

    Rao, S. S.

    1984-01-01

    The application of multiobjective optimization techniques to structural design problems involving uncertain parameters and random processes is studied. The design of a cantilever beam with a tip mass subjected to a stochastic base excitation is considered for illustration. Several of the problem parameters are assumed to be random variables and the structural mass, fatigue damage, and negative of natural frequency of vibration are considered for minimization. The solution of this three-criteria design problem is found by using global criterion, utility function, game theory, goal programming, goal attainment, bounded objective function, and lexicographic methods. It is observed that the game theory approach is superior in finding a better optimum solution, assuming the proper balance of the various objective functions. The procedures used in the present investigation are expected to be useful in the design of general dynamic systems involving uncertain parameters, stochastic process, and multiple objectives.

  16. A new smooth robust control design for uncertain nonlinear systems with non-vanishing disturbances

    NASA Astrophysics Data System (ADS)

    Xian, Bin; Zhang, Yao

    2016-06-01

    In this paper, we consider the control problem for a general class of nonlinear system subjected to uncertain dynamics and non-varnishing disturbances. A smooth nonlinear control algorithm is presented to tackle these uncertainties and disturbances. The proposed control design employs the integral of a nonlinear sigmoid function to compensate the uncertain dynamics, and achieve a uniformly semi-global practical asymptotic stable tracking control of the system outputs. A novel Lyapunov-based stability analysis is employed to prove the convergence of the tracking errors and the stability of the closed-loop system. Numerical simulation results on a two-link robot manipulator are presented to illustrate the performance of the proposed control algorithm comparing with the layer-boundary sliding mode controller and the robust of integration of sign of error control design. Furthermore, real-time experiment results for the attitude control of a quadrotor helicopter are also included to confirm the effectiveness of the proposed algorithm.

  17. Robust admissibility and admissibilisation of uncertain discrete singular time-delay systems

    NASA Astrophysics Data System (ADS)

    Cui, Yukang; Lam, James; Feng, Zhiguang; Shen, Jun

    2016-11-01

    This paper is concerned with the characterisation of robust admissibility and admissibilisation for uncertain discrete-time singular system with interval time-varying delay. Considering the norm-bounded uncertainty and the interval time-varying delay, a new comparison model is introduced to transform the original singular system into two connected subsystems. After this transformation, a singular system without uncertainty and delay can be handled by the Lyapunov-Krasovskii functional method. By virtue of the scaled small gain theorem, an admissibility condition of the original singular system is proposed in terms of linear matrix inequalities. Moreover, the problem of robust admissibilisation of uncertain discrete singular time-varying system is also studied by iterative linear matrix inequality algorithm with initial condition optimisation. Several numerical examples are used to illustrate that the results are less conservative than existing ones.

  18. Structure Identification of Uncertain Complex Networks Based on Anticipatory Projective Synchronization.

    PubMed

    Heng, Liu; Xingyuan, Wang; Guozhen, Tan

    2015-01-01

    This paper investigates a method to identify uncertain system parameters and unknown topological structure in general complex networks with or without time delay. A complex network, which has uncertain topology and unknown parameters, is designed as a drive network, and a known response complex network with an input controller is designed to identify the drive network. Under the proposed input controller, the drive network and the response network can achieve anticipatory projective synchronization when the system is steady. Lyapunov theorem and Barbǎlat's lemma guarantee the stability of synchronization manifold between two networks. When the synchronization is achieved, the system parameters and topology in response network can be changed to equal with the parameters and topology in drive network. A numerical example is given to show the effectiveness of the proposed method.

  19. Single-axis gyroscopic motion with uncertain angular velocity about spin axis

    NASA Technical Reports Server (NTRS)

    Singh, S. N.

    1977-01-01

    A differential game approach is presented for studying the response of a gyro by treating the controlled angular velocity about the input axis as the evader, and the bounded but uncertain angular velocity about the spin axis as the pursuer. When the uncertain angular velocity about the spin axis desires to force the gyro to saturation a differential game problem with two terminal surfaces results, whereas when the evader desires to attain the equilibrium state the usual game with single terminal manifold arises. A barrier, delineating the capture zone (CZ) in which the gyro can attain saturation and the escape zone (EZ) in which the evader avoids saturation is obtained. The CZ is further delineated into two subregions such that the states in each subregion can be forced on a definite target manifold. The application of the game theoretic approach to Control Moment Gyro is briefly discussed.

  20. An efficient sampling algorithm for uncertain abnormal data detection in biomedical image processing and disease prediction.

    PubMed

    Liu, Fei; Zhang, Xi; Jia, Yan

    2015-01-01

    In this paper, we propose a computer information processing algorithm that can be used for biomedical image processing and disease prediction. A biomedical image is considered a data object in a multi-dimensional space. Each dimension is a feature that can be used for disease diagnosis. We introduce a new concept of the top (k1,k2) outlier. It can be used to detect abnormal data objects in the multi-dimensional space. This technique focuses on uncertain space, where each data object has several possible instances with distinct probabilities. We design an efficient sampling algorithm for the top (k1,k2) outlier in uncertain space. Some improvement techniques are used for acceleration. Experiments show our methods' high accuracy and high efficiency.

  1. Model Based Optimization of Integrated Low Voltage DC-DC Converter for Energy Harvesting Applications

    NASA Astrophysics Data System (ADS)

    Jayaweera, H. M. P. C.; Muhtaroğlu, Ali

    2016-11-01

    A novel model based methodology is presented to determine optimal device parameters for the fully integrated ultra low voltage DC-DC converter for energy harvesting applications. The proposed model feasibly contributes to determine the maximum efficient number of charge pump stages to fulfill the voltage requirement of the energy harvester application. The proposed DC-DC converter based power consumption model enables the analytical derivation of the charge pump efficiency when utilized simultaneously with the known LC tank oscillator behavior under resonant conditions, and voltage step up characteristics of the cross-coupled charge pump topology. The verification of the model has been done using a circuit simulator. The optimized system through the established model achieves more than 40% maximum efficiency yielding 0.45 V output with single stage, 0.75 V output with two stages, and 0.9 V with three stages for 2.5 kΩ, 3.5 kΩ and 5 kΩ loads respectively using 0.2 V input.

  2. An Integrated Programmable Wide-range PLL for Switching Synchronization in Isolated DC-DC Converters

    NASA Astrophysics Data System (ADS)

    Fard, Miad

    In this thesis, two Phase-Locked-Loop (PLL) based synchronization schemes are introduced and applied to a bi-directional Dual-Active-Bridge (DAB) dc-dc converter with an input voltage up to 80 V switching in the range of 250 kHz to 1 MHz. The two schemes synchronize gating signals across an isolated boundary without the need for an isolator per transistor. The Power Transformer Sensing (PTS) method utilizes the DAB power transformer to indirectly sense switching on the secondary side of the boundary, while the Digital Isolator Sensing (DIS) method utilizes a miniature transformer for synchronization and communication at up to 100 MHz. The PLL is implemented on-chip, and is used to control an external DAB power-stage. This work will lead to lower cost, high-frequency isolated dc-dc converters needed for a wide variety of emerging low power applications where isolator cost is relatively high and there is a demand for the reduction of parts.

  3. Static and Dynamic Characteristics of DC-DC Converter Using a Digital Filter

    NASA Astrophysics Data System (ADS)

    Kurokawa, Fujio; Okamatsu, Masashi

    This paper presents the regulation and dynamic characteristics of the dc-dc converter with digital PID control, the minimum phase FIR filter or the IIR filter, and then the design criterion to improve the dynamic characteristics is discussed. As a result, it is clarified that the DC-DC converter using the IIR filter method has superior performance characteristics. The regulation range is within 1.3%, the undershoot against the step change of the load is less than 2% and the transient time is less than 0.4ms with the IIR filter method. In this case, the switching frequency is 100kHz and the step change of the load R is from 50 Ω to 10 Ω. Further, the superior characteristics are obtained when the first gain, the second gain and the second cut-off frequency are relatively large, and the first cut-off frequency and the passing frequency are relatively low. Moreover, it is important that the gain strongly decreases at the second cut-off frequency because the upper band pass frequency range must be always less than half of the sampling frequency based on the sampling theory.

  4. Bifurcation Analysis of a DC-DC Bidirectional Power Converter Operating with Constant Power Loads

    NASA Astrophysics Data System (ADS)

    Cristiano, Rony; Pagano, Daniel J.; Benadero, Luis; Ponce, Enrique

    Direct current (DC) microgrids (MGs) are an emergent option to satisfy new demands for power quality and integration of renewable resources in electrical distribution systems. This work addresses the large-signal stability analysis of a DC-DC bidirectional converter (DBC) connected to a storage device in an islanding MG. This converter is responsible for controlling the balance of power (load demand and generation) under constant power loads (CPLs). In order to control the DC bus voltage through a DBC, we propose a robust sliding mode control (SMC) based on a washout filter. Dynamical systems techniques are exploited to assess the quality of this switching control strategy. In this sense, a bifurcation analysis is performed to study the nonlinear stability of a reduced model of this system. The appearance of different bifurcations when load parameters and control gains are changed is studied in detail. In the specific case of Teixeira Singularity (TS) bifurcation, some experimental results are provided, confirming the mathematical predictions. Both a deeper insight in the dynamic behavior of the controlled system and valuable design criteria are obtained.

  5. Light weight, high power, high voltage dc/dc converter technologies

    NASA Technical Reports Server (NTRS)

    Kraus, Robert; Myers, Ira; Baumann, Eric

    1990-01-01

    Power-conditioning weight reductions by orders of magnitude will be required to enable the megawatt-power-level space systems envisioned by the Strategic Defense Initiative, the Air Force, and NASA. An interagency program has been initiated to develop an 0.1-kg/kW dc/dc converter technology base for these future space applications. Three contractors are in the first phase of a competitive program to develop a megawatt dc/dc converter. Researchers at NASA Lewis Research Center are investigating innovative converter topology control. Three different converter subsystems based on square wave, resonant, and super-resonant topologies are being designed. The components required for the converter designs cover a wide array of technologies. Two different switches, one semiconductor and the other gas, are under development. Issues related to thermal management and material reliability for inductors, transformers, and capacitors are being investigated in order to maximize power density. A brief description of each of the concepts proposed to meet the goals of this program is presented.

  6. Thermoelectric-Generator-Based DC-DC Conversion Networks for Automotive Applications

    NASA Astrophysics Data System (ADS)

    Li, Molan; Xu, Shaohui; Chen, Qiang; Zheng, Li-Rong

    2011-05-01

    Maximizing electrical energy generation through waste heat recovery is one of the modern research questions within automotive applications of thermoelectric (TE) technologies. This paper proposes a novel concept of distributed multisection multilevel DC-DC conversion networks based on thermoelectric generators (TEGs) for automotive applications. The concept incorporates a bottom-up design approach to collect, convert, and manage vehicle waste heat efficiently. Several state-of-the-art thermoelectric materials are analyzed for the purpose of power generation at each waste heat harvesting location on a vehicle. Optimal materials and TE couple configurations are suggested. Moreover, a comparison of prevailing DC-DC conversion techniques was made with respect to applications at each conversion level within the network. Furthermore, higher-level design considerations are discussed according to system specifications. Finally, a case study is performed to compare the performance of the proposed network and a traditional single-stage system. The results show that the proposed network enhances the system conversion efficiency by up to 400%.

  7. Hybrid DC/DC Converter for SAR Antenna Power Supply Unit

    NASA Astrophysics Data System (ADS)

    Calcatterra, Paolo; Galantini, Paolo; Scorzafava, Edmondo; Sagnelli, Salvatore; Benettin, Piero

    2014-08-01

    When distributed power supply is mandatory to provide full functional redundancy in a SAR application, a compact design to minimize size and weight became the main driver of the system.In this context a single hermetic DC/DC converter, including magnetic components, has been made in thick-film Hybrid technology.It is designed for state of the art electrical performance, minimum mass and size, maximum reliability for SAR application, where each transmitter / receiver module is powered by one dedicated DC/DC converterIt is characterised by a very simplified design approach to get high reliability and repeatability for large scale production.The Hybrid uses a standard thick film multilayer technology, currently in use for military and Space application.A few passive components are placed outside the Hybrid according to desired Conducted Emission / Susceptibility performance requirements (input and output filters).The Hybrid is manufactured with multilayer ceramic substrate with ad-hoc solution to manage thermal and cross talk signal issues.The trimming of the PSU is via laser active trimming performed during Hybrid manufacturing. No further trimming is needed.The process control is performed according to MIL PRF 38534.The Hybrid is manufactured according ECSS-Q-ST-60- 05C.

  8. Sliding mode control with self-tuning law for uncertain nonlinear systems.

    PubMed

    Kuo, Tzu-Chun; Huang, Ying-Jeh; Chang, Shin-Hung

    2008-04-01

    A robust sliding mode control that follows a self-tuning law for nonlinear systems possessing uncertain parameters is proposed. The adjustable control gain and a bipolar sigmoid function are on-line tuned to force the tracking error to approach zero. Control system stability is ensured using the Lyapunov method. Both simulation and experimental application of a planetary gear type inverted pendulum control system verify the effectiveness of the developed approach.

  9. Compete, coordinate, and cooperate: How to exploit uncertain environments with social interaction.

    PubMed

    Schulze, Christin; Newell, Ben R

    2015-10-01

    Countless decisions, from the trivial to the crucial, are made in complex social contexts while facing uncertain consequences. Yet a large portion of decision making research focuses on either the effects of social interaction or the effects of environmental uncertainty by examining strategic games against others or individual games against nature. Drawing a connection between these approaches, the authors extend a standard individual choice paradigm to include social interaction with 1 other person. In this paradigm, 2 competing decision makers repeatedly select among 2 options, each offering a particular probability of a fixed payoff. When both players choose the same, correct option, the payoff is evenly split; when they choose different options, the player choosing the correct option receives the full payoff. The addition of this social dimension gives players an opportunity to fully exploit an uncertain environment via cooperation: By consistently choosing opposite options, two players can exploit the uncertain environment more effectively than a single player could. We present 2 experiments that manipulate environmental (Experiment 1) and social (Experiment 2) aspects of the paradigm. In Experiment 1, the outcome probabilities were either known or unknown to participants; in Experiment 2, participants' attention was drawn to individual or group gains by introducing either within- or between-group competition. Efficient cooperation did not emerge spontaneously in Experiment 1. Instead, most people probability maximized, mirroring the behavior observed in individual choice. By contrast, between--group competition in Experiment 2 facilitated efficient-but not always equitable--exploitation of uncertain environments. This work links the concepts of individual risky choice and strategic decision making under both environmental and social uncertainty.

  10. The Uncertainty Threshold Principle: Some Fundamental Limitations of Optimal Decision Making Under Dynamic Uncertainity

    NASA Technical Reports Server (NTRS)

    Athans, M.; Ku, R.; Gershwin, S. B.

    1977-01-01

    This note shows that the optimal control of dynamic systems with uncertain parameters has certain limitations. In particular, by means of a simple scalar linear-quadratic optimal control example, it is shown that the infinite horizon solution does not exist if the parameter uncertainty exceeds a certain quantifiable threshold; we call this the uncertainty threshold principle. The philosophical and design implications of this result are discussed.

  11. Robust fuel- and time-optimal control of uncertain flexible space structures

    NASA Technical Reports Server (NTRS)

    Wie, Bong; Sinha, Ravi; Sunkel, John; Cox, Ken

    1993-01-01

    The problem of computing open-loop, fuel- and time-optimal control inputs for flexible space structures in the face of modeling uncertainty is investigated. Robustified, fuel- and time-optimal pulse sequences are obtained by solving a constrained optimization problem subject to robustness constraints. It is shown that 'bang-off-bang' pulse sequences with a finite number of switchings provide a practical tradeoff among the maneuvering time, fuel consumption, and performance robustness of uncertain flexible space structures.

  12. Adaptive Control for Uncertain Nonlinear Multi-Input Multi-Output Systems

    NASA Technical Reports Server (NTRS)

    Cao, Chengyu (Inventor); Hovakimyan, Naira (Inventor); Xargay, Enric (Inventor)

    2014-01-01

    Systems and methods of adaptive control for uncertain nonlinear multi-input multi-output systems in the presence of significant unmatched uncertainty with assured performance are provided. The need for gain-scheduling is eliminated through the use of bandwidth-limited (low-pass) filtering in the control channel, which appropriately attenuates the high frequencies typically appearing in fast adaptation situations and preserves the robustness margins in the presence of fast adaptation.

  13. Stability Analysis of Uncertain Switched Delay Systems: A Time-Varying Lyapunov Function Approach

    NASA Astrophysics Data System (ADS)

    Huang, Ganji; Luo, Shixian; Chen, Wu-Hua

    Exponential stability for switched systems with uncertain parameters and time-varying delay is considered in this paper. The parametric uncertainties are assumed to be time-varying and norm-bounded. By introducing a novel piecewise time-varying Lyapunov function and using Razumikhin techniques, some linear matrix inequalities (LMIs) stability criteria are derived to guarantee the exponential stability of the switched delay systems. A numerical example is presented to demonstrate the effectiveness of the proposed method.

  14. Prediction of radiated emissions from DC motors

    NASA Astrophysics Data System (ADS)

    Suriano, Candace Rogers

    DC motors are known sources of radio frequency electromagnetic noise produced by arcing at the motor brushes. A simplified model of electromagnetic radiation from a DC motor and associated wiring harness is desired to guide engineers in the design process. Of particular interest is their behavior at low frequencies in a reverberation chamber. Different methods are used to devise a voltage transfer function between a device under test (DUT) and a monopole antenna for near field low frequency testing in a reverberation chamber. A simple scaling factor is used to transform low frequency monopole antenna data between different reverberation chamber configurations. Further refinement in the modeling is based on common mode current. Test data indicated that a simple equivalent RLC circuit could represent the common mode current. The validity of the approach is shown using the Electric Field Integral Equation. Various quasi-static and static models were used to compute the circuit parameters. Furthermore, a second circuit was shown to relate the common mode current to the receiving antenna voltage. Moment method models and test data demonstrate this relationship.

  15. The Complete Chloroplast Genome Sequences of Six Rehmannia Species

    PubMed Central

    Zeng, Shuyun; Zhou, Tao; Han, Kai; Yang, Yanci; Zhao, Jianhua; Liu, Zhan-Lin

    2017-01-01

    Rehmannia is a non-parasitic genus in Orobanchaceae including six species mainly distributed in central and north China. Its phylogenetic position and infrageneric relationships remain uncertain due to potential hybridization and polyploidization. In this study, we sequenced and compared the complete chloroplast genomes of six Rehmannia species using Illumina sequencing technology to elucidate the interspecific variations. Rehmannia plastomes exhibited typical quadripartite and circular structures with good synteny of gene order. The complete genomes ranged from 153,622 bp to 154,055 bp in length, including 133 genes encoding 88 proteins, 37 tRNAs, and 8 rRNAs. Three genes (rpoA, rpoC2, accD) have potentially experienced positive selection. Plastome size variation of Rehmannia was mainly ascribed to the expansion and contraction of the border regions between the inverted repeat (IR) region and the single-copy (SC) regions. Despite of the conserved structure in Rehmannia plastomes, sequence variations provide useful phylogenetic information. Phylogenetic trees of 23 Lamiales species reconstructed with the complete plastomes suggested that Rehmannia was monophyletic and sister to the clade of Lindenbergia and the parasitic taxa in Orobanchaceae. The interspecific relationships within Rehmannia were completely different with the previous studies. In future, population phylogenomic works based on plastomes are urgently needed to clarify the evolutionary history of Rehmannia. PMID:28294981

  16. Fusion protein of mutant B7-DC and Fc enhances the antitumor immune effect of GM-CSF-secreting whole-cell vaccine.

    PubMed

    Kojima, Masatsugu; Murata, Satoshi; Mekata, Eiji; Takebayashi, Katsushi; Jaffee, Elizabeth M; Tani, Tohru

    2014-04-01

    B7-DC [also known as programmed death ligand 2 (PD-L2)] is a costimulatory molecule expressed predominantly on dendritic cells (DCs) and macrophages. In addition to its coinhibitory receptor, programmed death receptor 1 (PD-1), evidence suggests that B7-DC interacts with an unidentified costimulatory receptor on T cells. B7-DC mutants with selective binding capacity for the costimulatory receptor may be effective in stimulating antitumor immune responses, while avoiding the inhibitory effects of PD-1. In this study, we concomitantly administered a GM-CSF-secreting whole-cell vaccine together with a fusion protein of mutant B7-DC and Fc portion (mB7-DC-Fc), which binds selectively to the costimulatory receptor. This lead to an increased number of tumor antigen-specific cytotoxic T lymphocytes both in the spleen and at the tumor site and complete elimination of established tumors in vivo. In addition, mB7-DC-Fc increased IFN-γ and IL-2 production and decreased IL-4 and IL-10 production in vitro, indicating that mB7-DC-Fc tips the Th1/Th2 balance toward Th1 dominance, which is more favorable for antitumor immunity. Furthermore, mB7-DC-Fc decreased the PD-1(+) proportion of CD8(+) T cells in vitro and tumor-infiltrating CD8(+) T cells in vivo, suggesting that mB7-DC-Fc may maintain tumor-infiltrating CD8(+) T cells in a nonexhausted state. In conclusion, mB7-DC-Fc administration during the T-cell priming phase enhances antitumor effects of vaccine by generating more tumor antigen-specific cytotoxic T lymphocytes and leading to their accumulation at the tumor site. We suggest that this combination approach may be a promising strategy for antitumor immunotherapy.

  17. Simulation of the dc Plasma in Carbon Nanotube Growth

    NASA Technical Reports Server (NTRS)

    Hash, David; Bose, Deepak; Govindan, T. R.; Meyyappan, M.; Biegel, Bryan (Technical Monitor)

    2003-01-01

    A model for the dc plasma used in carbon nanotube growth is presented, and one-dimensional simulations of an acetylene/ammonia/argon system are performed. The effect of dc bias is illustrated by examining electron temperature, electron and ion densities, and neutral densities. Introducing a tungsten filament in the dc plasma, as in hot filament chemical vapor deposition with plasma assistance, shows negligible influence on the system characteristics.

  18. Variable Rail Voltage Control of a Brushless DC (BLDC) Motor

    DTIC Science & Technology

    2013-01-01

    Variable Rail Voltage Control of a Brushless DC ( BLDC ) Motor by Yuan Chen, Joseph Conroy, and William Nothwang ARL-TR-6308 January 2013...TR-6308 January 2013 Variable Rail Voltage Control of a Brushless DC ( BLDC ) Motor Yuan Chen, Joseph Conroy, and William Nothwang Sensors...DATES COVERED (From - To) 4. TITLE AND SUBTITLE Variable Rail Voltage Control of a Brushless DC ( BLDC ) Motor 5a. CONTRACT NUMBER 5b. GRANT

  19. Discretisation and control of polytopic systems with uncertain sampling rates and network-induced delays

    NASA Astrophysics Data System (ADS)

    Braga, Márcio F.; Morais, Cecília F.; Tognetti, Eduardo S.; Oliveira, Ricardo C. L. F.; Peres, Pedro L. D.

    2014-11-01

    This paper investigates the problems of uncertain sampling rate discretisation and the networked control of uncertain time-invariant continuous-time linear systems in polytopic domains. The sampling period is assumed to be unknown but belonging to a given interval. To avoid the difficulty of dealing with the exponential of uncertain matrices, a discrete-time model is obtained by applying a Taylor series expansion of degree ℓ to the original system. The resulting discrete-time model is composed of homogeneous polynomial matrices with parameters lying in the Cartesian product of simplexes, called a multi-simplex, plus an additive norm-bounded term representing the discretisation residual error. The original continuous-time system is controlled through a communication network that introduces a time delay in the process. Linear matrix inequality relaxations that include a scalar parameter search are proposed for the design of a digital robust state feedback controller that guarantees the closed-loop stability of the networked control system. Numerical experiments are presented to illustrate the versatility of the proposed method, which can be applied to a more general class of networked control problems than the existing approaches in the literature.

  20. Brake squeal reduction of vehicle disc brake system with interval parameters by uncertain optimization

    NASA Astrophysics Data System (ADS)

    Lü, Hui; Yu, Dejie

    2014-12-01

    An uncertain optimization method for brake squeal reduction of vehicle disc brake system with interval parameters is presented in this paper. In the proposed method, the parameters of frictional coefficient, material properties and the thicknesses of wearing components are treated as uncertain parameters, which are described as interval variables. Attention is focused on the stability analysis of a brake system in squeal, and the stability of brake system is investigated via the complex eigenvalue analysis (CEA) method. The dominant unstable mode is extracted by performing CEA based on a linear finite element (FE) model, and the negative damping ratio corresponding to the dominant unstable mode is selected as the indicator of instability. The response surface method (RSM) is applied to approximate the implicit relationship between the unstable mode and the system parameters. A reliability-based optimization model for improving the stability of the vehicle disc brake system with interval parameters is constructed based on RSM, interval analysis and reliability analysis. The Genetic Algorithm is used to get the optimal values of design parameters from the optimization model. The stability analysis and optimization of a disc brake system are carried out, and the results show that brake squeal propensity can be reduced by using stiffer back plates. The proposed approach can be used to improve the stability of the vehicle disc brake system with uncertain parameters effectively.