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Sample records for neutral network based

  1. Neural network based neutral particles reconstruction with the E687 hadron calorimeter

    NASA Astrophysics Data System (ADS)

    Arena, V.; Boca, G.; Bonomi, G.; Gérard, G.; Gianini, G.; Marchesotti, M.; Merlo, M.; Ratti, S. P.; Riccardi, C.; Viola, L.; Vitulo, P.; Buchholz, D.; Claes, D.; O'Reilly, B.

    1996-02-01

    We present a neutral particle reconstruction algorithm based on a neural network approach applied to the E687 hadron calorimeter. A measurement of the invariant mass of the Σ± → nπ± is presented to verify the reliability of the reconstruction. The reconstructed invariant mass of the charmed meson D + → K L0π+π+π- is also presented to show the possible application of this technique to charmed particles decaying into a neutral hadron. An example of this would be Λc+ → nK -π+π+.

  2. Camera characterization using back-propagation artificial neutral network based on Munsell system

    NASA Astrophysics Data System (ADS)

    Liu, Ye; Yu, Hongfei; Shi, Junsheng

    2008-02-01

    The camera output RGB signals do not directly corresponded to the tristimulus values based on the CIE standard colorimetric observer, i.e., it is a device-independent color space. For achieving accurate color information, we need to do color characterization, which can be used to derive a transformation between camera RGB values and CIE XYZ values. In this paper we set up a Back-Propagation (BP) artificial neutral network to realize the mapping from camera RGB to CIE XYZ. We used the Munsell Book of Color with total number 1267 as color samples. Each patch of the Munsell Book of Color was recorded by camera, and the RGB values could be obtained. The Munsell Book of Color were taken in a light booth and the surround was kept dark. The viewing/illuminating geometry was 0/45 using D 65 illuminate. The lighting illuminating the reference target needs to be as uniform as possible. The BP network was a 5-layer one and (3-10-10-10-3), which was selected through our experiments. 1000 training samples were selected randomly from the 1267 samples, and the rest 267 samples were as the testing samples. Experimental results show that the mean color difference between the reproduced colors and target colors is 0.5 CIELAB color-difference unit, which was smaller than the biggest acceptable color difference 2 CIELAB color-difference unit. The results satisfy some applications for the more accurate color measurements, such as medical diagnostics, cosmetics production, the color reappearance of different media, etc.

  3. Empirical evaluation of neutral interactions in host-parasite networks.

    PubMed

    Canard, E F; Mouquet, N; Mouillot, D; Stanko, M; Miklisova, D; Gravel, D

    2014-04-01

    While niche-based processes have been invoked extensively to explain the structure of interaction networks, recent studies propose that neutrality could also be of great importance. Under the neutral hypothesis, network structure would simply emerge from random encounters between individuals and thus would be directly linked to species abundance. We investigated the impact of species abundance distributions on qualitative and quantitative metrics of 113 host-parasite networks. We analyzed the concordance between neutral expectations and empirical observations at interaction, species, and network levels. We found that species abundance accurately predicts network metrics at all levels. Despite host-parasite systems being constrained by physiology and immunology, our results suggest that neutrality could also explain, at least partially, their structure. We hypothesize that trait matching would determine potential interactions between species, while abundance would determine their realization. PMID:24642492

  4. Stability of Stochastic Neutral Cellular Neural Networks

    NASA Astrophysics Data System (ADS)

    Chen, Ling; Zhao, Hongyong

    In this paper, we study a class of stochastic neutral cellular neural networks. By constructing a suitable Lyapunov functional and employing the nonnegative semi-martingale convergence theorem we give some sufficient conditions ensuring the almost sure exponential stability of the networks. The results obtained are helpful to design stability of networks when stochastic noise is taken into consideration. Finally, two examples are provided to show the correctness of our analysis.

  5. Synchronization of Neural Networks of Neutral Type with Stochastic Perturbation

    NASA Astrophysics Data System (ADS)

    Park, Ju H.; Kwon, O. M.

    In this letter, the problem of feedback controller design to achieve synchronization for neural network of neutral type with stochastic perturbation is considered. Based on Lyapunov method and LMI (linear matrix inequality) framework, the goal of this letter is to derive an existence criterion of the controller for the synchronization between master and response networks.

  6. New LMI-Based Passivity Criteria for Neutral-Type BAM Neural Networks with Randomly Occurring Uncertainties

    NASA Astrophysics Data System (ADS)

    Sakthivel, R.; Anbuvithya, R.; Mathiyalagan, K.; Arunkumar, A.; Prakash, P.

    2013-12-01

    In this paper, we study the passivity analysis for a class of neutral-type BAM neural networks with time-varying delays and randomly occurring uncertainties as well as generalized activation functions. Linear matrix inequality (LMI) approach together with the construction of proper Lyapunov-Krasovskii functional involving triple integrals and augmented type constraint is implemented to derive a new set of sufficient conditions for obtaining the required result. More precisely, first we derive the passivity condition for BAM neural networks without uncertainties and then the result is extended to the case with randomly occurring uncertainties. In particular, the presented results depend not only upon discrete delay but also distributed time varying delay. The obtained passivity conditions are formulated in terms of linear matrix inequalities that can be easily solved by using the MATLAB-LMI toolbox. Finally, the effectiveness of the proposed passivity criterion is demonstrated through numerical example.

  7. Monochromaticity in neutral evolutionary network models.

    PubMed

    Halu, Arda; Bianconi, Ginestra

    2012-12-01

    Recent studies on epistatic networks of model organisms have unveiled a certain type of modular property called monochromaticity in which the networks are clustered into functional modules that interact with each other through the same type of epistasis. Here, we propose and study three epistatic network models that are inspired by the duplication-divergence mechanism to gain insight into the evolutionary basis of monochromaticity and to test if it can be explained as the outcome of a neutral evolutionary hypothesis. We show that the epistatic networks formed by these stochastic evolutionary models have monochromaticity conflict distributions that are centered close to zero and are statistically significantly different from their randomized counterparts. In particular, the last model we propose yields a strictly monochromatic solution. Our results agree with the monochromaticity findings in real organisms and point toward the possible role of a neutral mechanism in the evolution of this phenomenon. PMID:23367998

  8. Monochromaticity in neutral evolutionary network models

    NASA Astrophysics Data System (ADS)

    Halu, Arda; Bianconi, Ginestra

    2012-12-01

    Recent studies on epistatic networks of model organisms have unveiled a certain type of modular property called monochromaticity in which the networks are clustered into functional modules that interact with each other through the same type of epistasis. Here, we propose and study three epistatic network models that are inspired by the duplication-divergence mechanism to gain insight into the evolutionary basis of monochromaticity and to test if it can be explained as the outcome of a neutral evolutionary hypothesis. We show that the epistatic networks formed by these stochastic evolutionary models have monochromaticity conflict distributions that are centered close to zero and are statistically significantly different from their randomized counterparts. In particular, the last model we propose yields a strictly monochromatic solution. Our results agree with the monochromaticity findings in real organisms and point toward the possible role of a neutral mechanism in the evolution of this phenomenon.

  9. Role of neutral wind in the performance of artificial neural-network based TEC models at diverse longitudes in the low latitudes

    NASA Astrophysics Data System (ADS)

    Sur, D.; Ray, S.; Paul, A.

    2015-03-01

    The equatorial ionosphere is characterized by (i) large values of total electron content (TEC) and sharp latitudinal gradients of TEC, (ii) steep temporal variation of TEC, (iii) large diurnal variation of TEC, and (iv) postsunset secondary enhancement of TEC. These features cause major limitations in the accuracy of standard ionospheric TEC models in this region. Three artificial neural-network (ANN) based models have been developed based on real-time low-latitude TEC data along 77°E, 88°E, and 121°E longitudes in the region between the magnetic equator and locations beyond the northern crest of equatorial ionization anomaly to predict the vertical TEC values. ANN models have shown more accurate predictions than other standard ionospheric TEC models like International Reference Ionosphere, Parameterized Ionospheric Model, and NeQuick. The effects of the neutral wind in the variation of TEC are significant and have been incorporated as inputs to these ANN models. The outputs with neutral wind incorporated shows better correspondence with measured TEC than the models without neutral wind inputs. The longitudinally separated models have been used to find any longitudinal differences in TEC along equatorial regions. The causes behind the longitudinal differences in TEC and its diurnal variations in these regions have been explained in terms of the geomagnetic declination and inclination angles along with the role of zonal wind.

  10. Electronic hardware implementations of neutral networks

    NASA Technical Reports Server (NTRS)

    Thakoor, A. P.; Moopenn, A.; Lambe, John; Khanna, S. K.

    1987-01-01

    This paper examines some of the present work on the development of electronic neural network hardware. In particular, the investigations currently under way at JPL on neural network hardware implementations based on custom VLSI technology, novel thin film materials, and an analog-digital hybrid architecture are reviewed. The availability of such hardware will greatly benefit and enhance the present intense research effort on the potential computational capabilities of highly parallel systems based on neural network models.

  11. Emergence of structural patterns in neutral trophic networks.

    PubMed

    Canard, Elsa; Mouquet, Nicolas; Marescot, Lucile; Gaston, Kevin J; Gravel, Dominique; Mouillot, David

    2012-01-01

    Interaction networks are central elements of ecological systems and have very complex structures. Historically, much effort has focused on niche-mediated processes to explain these structures, while an emerging consensus posits that both niche and neutral mechanisms simultaneously shape many features of ecological communities. However, the study of interaction networks still lacks a comprehensive neutral theory. Here we present a neutral model of predator-prey interactions and analyze the structural characteristics of the simulated networks. We find that connectance values (complexity) and complexity-diversity relationships of neutral networks are close to those observed in empirical bipartite networks. High nestedness and low modularity values observed in neutral networks fall in the range of those from empirical antagonist bipartite networks. Our results suggest that, as an alternative to niche-mediated processes that induce incompatibility between species ("niche forbidden links"), neutral processes create "neutral forbidden links" due to uneven species abundance distributions and the low probability of interaction between rare species. Neutral trophic networks must be seen as the missing endpoint of a continuum from niche to purely stochastic approaches of community organization. PMID:22899987

  12. Periodic oscillation for a Hopfield neural networks with neutral delays

    NASA Astrophysics Data System (ADS)

    Gui, Zhanji; Ge, Weigao; Yang, Xiao-Song

    2007-04-01

    In this Letter, a Hopfield neural networks model with neutral delay are investigated by means of an abstract continuous theorem of k-set contractive operator and some analysis technique. Sufficient conditions are obtained for the existence of periodic solutions.

  13. Analysis on Global Stability of Stochastic Neural Networks of Neutral Type

    NASA Astrophysics Data System (ADS)

    Park, Ju H.; Kwon, O. M.

    In this paper, the problem of global asymptotic stability of stochastic neural networks of neutral type is considered. Based on the Lyapunov stability theory, a new delay-dependent stability criterion for the network is derived in terms of LMI (linear matrix inequality). A numerical example is given to show the effectiveness of the proposed method.

  14. A Multi-Hop Energy Neutral Clustering Algorithm for Maximizing Network Information Gathering in Energy Harvesting Wireless Sensor Networks.

    PubMed

    Yang, Liu; Lu, Yinzhi; Zhong, Yuanchang; Wu, Xuegang; Yang, Simon X

    2015-01-01

    Energy resource limitation is a severe problem in traditional wireless sensor networks (WSNs) because it restricts the lifetime of network. Recently, the emergence of energy harvesting techniques has brought with them the expectation to overcome this problem. In particular, it is possible for a sensor node with energy harvesting abilities to work perpetually in an Energy Neutral state. In this paper, a Multi-hop Energy Neutral Clustering (MENC) algorithm is proposed to construct the optimal multi-hop clustering architecture in energy harvesting WSNs, with the goal of achieving perpetual network operation. All cluster heads (CHs) in the network act as routers to transmit data to base station (BS) cooperatively by a multi-hop communication method. In addition, by analyzing the energy consumption of intra- and inter-cluster data transmission, we give the energy neutrality constraints. Under these constraints, every sensor node can work in an energy neutral state, which in turn provides perpetual network operation. Furthermore, the minimum network data transmission cycle is mathematically derived using convex optimization techniques while the network information gathering is maximal. Simulation results show that our protocol can achieve perpetual network operation, so that the consistent data delivery is guaranteed. In addition, substantial improvements on the performance of network throughput are also achieved as compared to the famous traditional clustering protocol LEACH and recent energy harvesting aware clustering protocols. PMID:26712764

  15. A Multi-Hop Energy Neutral Clustering Algorithm for Maximizing Network Information Gathering in Energy Harvesting Wireless Sensor Networks

    PubMed Central

    Yang, Liu; Lu, Yinzhi; Zhong, Yuanchang; Wu, Xuegang; Yang, Simon X.

    2015-01-01

    Energy resource limitation is a severe problem in traditional wireless sensor networks (WSNs) because it restricts the lifetime of network. Recently, the emergence of energy harvesting techniques has brought with them the expectation to overcome this problem. In particular, it is possible for a sensor node with energy harvesting abilities to work perpetually in an Energy Neutral state. In this paper, a Multi-hop Energy Neutral Clustering (MENC) algorithm is proposed to construct the optimal multi-hop clustering architecture in energy harvesting WSNs, with the goal of achieving perpetual network operation. All cluster heads (CHs) in the network act as routers to transmit data to base station (BS) cooperatively by a multi-hop communication method. In addition, by analyzing the energy consumption of intra- and inter-cluster data transmission, we give the energy neutrality constraints. Under these constraints, every sensor node can work in an energy neutral state, which in turn provides perpetual network operation. Furthermore, the minimum network data transmission cycle is mathematically derived using convex optimization techniques while the network information gathering is maximal. Simulation results show that our protocol can achieve perpetual network operation, so that the consistent data delivery is guaranteed. In addition, substantial improvements on the performance of network throughput are also achieved as compared to the famous traditional clustering protocol LEACH and recent energy harvesting aware clustering protocols. PMID:26712764

  16. Seismic active control by neutral networks

    SciTech Connect

    Tang, Yu

    1995-12-31

    A study on the application of artificial neural networks (ANNs) to active structural control under seismic loads is carried out. The structure considered is a single-degree-of-freedom (SDF) system with an active bracing device. The control force is computed by a trained neural network. The feedforward neural network architecture and an adaptive backpropagation training algorithm is used in the study. The neural net is trained to reproduce the function that represents the response-excitation relationship of the SDF system under seismic loads. The input-output training patterns are generated randomly. In the backpropagation training algorithm, the learning rate is determined by ensuring the decrease of the error function at each epoch. The computer program implemented is validated by solving the classification of the XOR problem. Then, the trained ANN is used to compute the control force according to the control strategy. If the control force exceeds the actuator`s capacity limit, it is set equal to that limit. The concept of the control strategy employed herein is to apply the control force at every time step to cancel the system velocity induced at the preceding time step so that the gradual rhythmic buildup of the response is destroyed. The ground motions considered in the numerical example are the 1940 El Centro earthquake and the 1979 Imperial Valley earthquake in California. The system responses with and without the control are calculated and compared. The feasibility and potential of applying ANNs to seismic active control is asserted by the promising results obtained from the numerical examples studied.

  17. Quantum Network of Atom Clocks: A Possible Implementation with Neutral Atoms.

    PubMed

    Kómár, P; Topcu, T; Kessler, E M; Derevianko, A; Vuletić, V; Ye, J; Lukin, M D

    2016-08-01

    We propose a protocol for creating a fully entangled Greenberger-Horne-Zeilinger-type state of neutral atoms in spatially separated optical atomic clocks. In our scheme, local operations make use of the strong dipole-dipole interaction between Rydberg excitations, which give rise to fast and reliable quantum operations involving all atoms in the ensemble. The necessary entanglement between distant ensembles is mediated by single-photon quantum channels and collectively enhanced light-matter couplings. These techniques can be used to create the recently proposed quantum clock network based on neutral atom optical clocks. We specifically analyze a possible realization of this scheme using neutral Yb ensembles. PMID:27541452

  18. Quantum Network of Atom Clocks: A Possible Implementation with Neutral Atoms

    NASA Astrophysics Data System (ADS)

    Kómár, P.; Topcu, T.; Kessler, E. M.; Derevianko, A.; Vuletić, V.; Ye, J.; Lukin, M. D.

    2016-08-01

    We propose a protocol for creating a fully entangled Greenberger-Horne-Zeilinger-type state of neutral atoms in spatially separated optical atomic clocks. In our scheme, local operations make use of the strong dipole-dipole interaction between Rydberg excitations, which give rise to fast and reliable quantum operations involving all atoms in the ensemble. The necessary entanglement between distant ensembles is mediated by single-photon quantum channels and collectively enhanced light-matter couplings. These techniques can be used to create the recently proposed quantum clock network based on neutral atom optical clocks. We specifically analyze a possible realization of this scheme using neutral Yb ensembles.

  19. A neutral model as a null hypothesis test for river network sinuosity

    NASA Astrophysics Data System (ADS)

    Gaucherel, C.; Salomon, L.

    2014-06-01

    Neutral models (NMs) are built to test null hypotheses and to detect properties at work in an object or a system. While several studies in geomorphology have used NMs without explicitly mentioning them or describing how they were built, it must be recognized that neutral models more often concerned theoretical explorations that drove such use. In this paper, we propose a panel of NMs of river (channel) networks based on a well-established relationship between observed and simulated sinuosity properties. We first simulated new instances of river networks with a (one-parameter) neutral model based on optimal channel networks (OCN) and leading to homogeneous sinuosity watersheds. We then proposed a "less neutral" model able to generate a variety of river networks accounting for the spatial heterogeneity of observed properties such as elevation. These models, providing confidence levels, allowed us to certify that some properties played a role in the generation of the observed network. Finally, we demonstrated and illustrated both models on the Bidasoa watershed (Spain-France frontier), with a new dedicated software (called SSM). NMs in geomorphology ensure to progressively help to identify the process operating in an observed object, and to ultimately improve our understanding of it (i.e. intrinsic need). But they also provide simulated samples statistically "similar" to an observed one, thus offering new alternatives to every process carried by the observed object (i.e. extrinsic need). Artificial river networks studied here would be of great value to environmental sciences studying geomorphology and freshwater-related processes.

  20. EDITORIAL: Negative ion based neutral beam injection

    NASA Astrophysics Data System (ADS)

    Hemsworth, R. S.

    2006-06-01

    It is widely recognized that neutral beam injection (NBI), i.e. the injection of high energy, high power, beams of H or D atoms, is a flexible and reliable system that has been the main heating system on a large variety of fusion devices, and NBI has been chosen as one of the three heating schemes of the International Tokomak Reactor (ITER). To date, all the NBI systems but two have been based on the neutralization (in a simple gas target) of positive hydrogen or deuterium ions accelerated to <100 keV/nucleon. Above that energy the neutralization of positive ions falls to unacceptably low values, and higher energy neutral beams have to be created by the neutralization of accelerated negative ions (in a simple gas target), as this remains high (approx60%) up to >1 MeV/nucleon. Unfortunately H- and D- are difficult to create, and the very characteristic that makes them attractive, the ease with which the electron is detached from the ion, means that it is difficult to create high concentrations or fluxes of them, and it is difficult to avoid substantial, collisional, losses in the extraction and acceleration processes. However, there has been impressive progress in negative ion sources and accelerators over the past decade, as demonstrated by the two pioneering, operational, multi-megawatt, negative ion based, NBI systems at LHD (180 keV, H0) and JT-60U (500 keV, D0), both in Japan. Nevertheless, the system proposed for ITER represents a substantial technological challenge as an increase is required in beam energy, to 1 MeV, D0, accelerated ion (D-) current, to 40 A, accelerated current density, 200 A m-2 of D-, and pulse length, to 1 h. At the Fourth IAEA Technical Meeting on Negative Ion Based Neutral Beam Injectors, hosted by the Consorzio RFX, Padova, Italy, 9-11 May 2005, the status of the R&D aimed at the realization of the injectors for ITER was presented. Because of the importance of this development to the success of the ITER project, participants at that

  1. Neutralization efficiency estimation in a neutral beam source based on inductively coupled plasma

    NASA Astrophysics Data System (ADS)

    Vozniy, O. V.; Yeom, G. Y.

    2009-01-01

    This study examined the optimal conditions of neutral beam generation to maintain a high degree of neutralization and focusing during beam energy variation for a neutral beam source based on inductively coupled plasma with a three-grid ion beam acceleration system. The neutral beam energy distribution was estimated by measuring the energy profiles of ions that "survived" the neutralization after reflection. The energy measurements of the primary and reflected ions showed narrow distribution functions, each with only one peak. At higher beam energies, both the ratio of the ion energy loss to the primary energy and the degree of energy divergence decreased, confirming the precise alignment of the neutral beam. The neutralization efficiency of the neutral beam source with a three-grid acceleration system was found to be affected mainly by the beam angle divergence rather than by the particle translation energy.

  2. Neutralization efficiency estimation in a neutral beam source based on inductively coupled plasma

    SciTech Connect

    Vozniy, O. V.; Yeom, G. Y.

    2009-01-01

    This study examined the optimal conditions of neutral beam generation to maintain a high degree of neutralization and focusing during beam energy variation for a neutral beam source based on inductively coupled plasma with a three-grid ion beam acceleration system. The neutral beam energy distribution was estimated by measuring the energy profiles of ions that 'survived' the neutralization after reflection. The energy measurements of the primary and reflected ions showed narrow distribution functions, each with only one peak. At higher beam energies, both the ratio of the ion energy loss to the primary energy and the degree of energy divergence decreased, confirming the precise alignment of the neutral beam. The neutralization efficiency of the neutral beam source with a three-grid acceleration system was found to be affected mainly by the beam angle divergence rather than by the particle translation energy.

  3. Bifurcation Analysis for Neural Networks in Neutral Form

    NASA Astrophysics Data System (ADS)

    Chen, Hong-Bing; Sun, Xiao-Ke

    2016-06-01

    In this paper, a system of neural networks in neutral form with time delay is investigated. Further, by introducing delay τ as a bifurcation parameter, it is found that Hopf bifurcation occurs when τ is across some critical values. The direction of the Hopf bifurcations and the stability are determined by using normal form method and center manifold theory. Next, the global existence of periodic solution is established by using a global Hopf bifurcation result. Finally, an example is given to support the theoretical predictions.

  4. Improved delay-dependent stability criteria for neutral Hopfield neural networks

    NASA Astrophysics Data System (ADS)

    Zang, Minglei; Wu, Linyao; She, Qiuye; Chu, Zhongyi

    2008-10-01

    The neutral Hopfield neural network (NHNN) model is considered in this paper, which can be regarded as an extension of the classical Hopfield neural network (HNN). By introducing the neutral term into the classical HNN model, the inspiration and associate memory phenomenon can be well described and explained. Based on LMI techniques, the delay-dependent stability criteria of NHNN are obtained using the free-weighting matrices method, where the free weighting matrices are applied to express the relationships between the terms in the Leibniz-Newton formula. The optimization on the free weighting matrices by means of solving linear matrix inequalities (LMIs) can be employed such that the less conservative results can be obtained than that in Zhang, et al 2005. The numerical examples demonstrate that the proposed stability criterion is less conservative than the previous works.

  5. In-silico studies of neutral drift for functional protein interaction networks

    NASA Astrophysics Data System (ADS)

    Ali, Md Zulfikar; Wingreen, Ned S.; Mukhopadhyay, Ranjan

    We have developed a minimal physically-motivated model of protein-protein interaction networks. Our system consists of two classes of enzymes, activators (e.g. kinases) and deactivators (e.g. phosphatases), and the enzyme-mediated activation/deactivation rates are determined by sequence-dependent binding strengths between enzymes and their targets. The network is evolved by introducing random point mutations in the binding sequences where we assume that each new mutation is either fixed or entirely lost. We apply this model to studies of neutral drift in networks that yield oscillatory dynamics, where we start, for example, with a relatively simple network and allow it to evolve by adding nodes and connections while requiring that dynamics be conserved. Our studies demonstrate both the importance of employing a sequence-based evolutionary scheme and the relative rapidity (in evolutionary time) for the redistribution of function over new nodes via neutral drift. Surprisingly, in addition to this redistribution time we discovered another much slower timescale for network evolution, reflecting hidden order in sequence space that we interpret in terms of sparsely connected domains.

  6. Why common carrier and network neutrality principles apply to the Nationwide Health Information Network (NWHIN)

    PubMed Central

    Gaynor, Mark; Lenert, Leslie; Wilson, Kristin D; Bradner, Scott

    2014-01-01

    The Office of the National Coordinator will be defining the architecture of the Nationwide Health Information Network (NWHIN) together with the proposed HealtheWay public/private partnership as a development and funding strategy. There are a number of open questions—for example, what is the best way to realize the benefits of health information exchange? How valuable are regional health information organizations in comparison with a more direct approach? What is the role of the carriers in delivering this service? The NWHIN is to exist for the public good, and thus shares many traits of the common law notion of ‘common carriage’ or ‘public calling,’ the modern term for which is network neutrality. Recent policy debates in Congress and resulting potential regulation have implications for key stakeholders within healthcare that use or provide services, and for those who exchange information. To date, there has been little policy debate or discussion about the implications of a neutral NWHIN. This paper frames the discussion for future policy debate in healthcare by providing a brief education and summary of the modern version of common carriage, of the key stakeholder positions in healthcare, and of the potential implications of the network neutrality debate within healthcare. PMID:23837992

  7. Global asymptotic stability analysis for neutral stochastic neural networks with time-varying delays

    NASA Astrophysics Data System (ADS)

    Su, Weiwei; Chen, Yiming

    2009-04-01

    In this paper, the global asymptotic stability is investigated for a class of neutral stochastic neural networks with time-varying delays and norm-bounded uncertainties. Based on Lyapunov stability theory and stochastic analysis approaches, delay-dependent criteria are derived to ensure the global, robust, asymptotic stability of the addressed system in the mean square for all admissible parameter uncertainties. The criteria can be checked easily by the LMI Control Toolbox in Matlab. A numerical example is given to illustrate the feasibility and effectiveness of the results.

  8. Generic properties of combinatory maps: Neutral networks of RNA secondary structures

    SciTech Connect

    Reidys, C. |; Stadler, P.F. |; Schuster, P. ||

    1997-03-01

    Random graph theory is used to model and analyze the relationships between sequences and secondary structures of RNA molecules, which are understood as mappings from sequence space into shape space. These maps are non-invertible since there are always many orders of magnitude more sequences than structures. Sequences folding into identical structures form neutral networks. A neutral network is embedded in the set of sequences that are compatible with the given structure. Networks are modeled as graphs and constructed by random choice of vertices from the space of compatible sequences. The theory characterizes neutral networks by the mean fraction of neutral neighbors ({lambda}). The networks are connected and percolate sequence space if the fraction of neutral nearest neighbors exceeds a threshold value ({lambda} > {lambda}*). Below threshold ({lambda} < {lambda}*), the networks are partitioned into a largest giant component and several smaller components. Structures are classified as common or rare according to the sizes of their pre-images, i.e. according to the fractions of sequences folding into them. The neutral networks of any pair of two different common structures almost touch each other, and, as expressed by the conjecture of shape space covering sequences folding into almost all common structures, can be found in a small ball of an arbitrary location in sequence space. The results from random graph theory are compared to data obtained by folding large samples of RNA sequences. Differences are explained in terms of specific features of RNA molecular structures.

  9. Identification of neutral biochemical network models from time series data

    PubMed Central

    Vilela, Marco; Vinga, Susana; Maia, Marco A Grivet Mattoso; Voit, Eberhard O; Almeida, Jonas S

    2009-01-01

    Background The major difficulty in modeling biological systems from multivariate time series is the identification of parameter sets that endow a model with dynamical behaviors sufficiently similar to the experimental data. Directly related to this parameter estimation issue is the task of identifying the structure and regulation of ill-characterized systems. Both tasks are simplified if the mathematical model is canonical, i.e., if it is constructed according to strict guidelines. Results In this report, we propose a method for the identification of admissible parameter sets of canonical S-systems from biological time series. The method is based on a Monte Carlo process that is combined with an improved version of our previous parameter optimization algorithm. The method maps the parameter space into the network space, which characterizes the connectivity among components, by creating an ensemble of decoupled S-system models that imitate the dynamical behavior of the time series with sufficient accuracy. The concept of sloppiness is revisited in the context of these S-system models with an exploration not only of different parameter sets that produce similar dynamical behaviors but also different network topologies that yield dynamical similarity. Conclusion The proposed parameter estimation methodology was applied to actual time series data from the glycolytic pathway of the bacterium Lactococcus lactis and led to ensembles of models with different network topologies. In parallel, the parameter optimization algorithm was applied to the same dynamical data upon imposing a pre-specified network topology derived from prior biological knowledge, and the results from both strategies were compared. The results suggest that the proposed method may serve as a powerful exploration tool for testing hypotheses and the design of new experiments. PMID:19416537

  10. The Neutral in A Communication Network Under Conditions of Conflict. A Technical Report.

    ERIC Educational Resources Information Center

    Ziller, Robert C.; And Others

    Two laboratory experiments are reported which describe the effects of the presence of a neutral in a communication network during the resolution of differences of opinion between two persons. The presence of a neutral was found to be associated with increased resistance to persuasion, increased number of messages between parties, and increased…

  11. Risk-neutral density extraction from option prices: improved pricing with mixture density networks.

    PubMed

    Schittenkopf, C; Dorffner, G

    2001-01-01

    One of the central goals in finance is to find better models for pricing and hedging financial derivatives such as call and put options. We present a new semi-nonparametric approach to risk-neutral density extraction from option prices, which is based on an extension of the concept of mixture density networks. The central idea is to model the shape of the risk-neutral density in a flexible, nonlinear way as a function of the time horizon. Thereby, stylized facts such as negative skewness and excess kurtosis are captured. The approach is applied to a very large set of intraday options data on the FTSE 100 recorded at LIFFE. It is shown to yield significantly better results in terms of out-of-sample pricing accuracy in comparison to the basic and an extended Black-Scholes model. It is also significantly better than a more elaborate GARCH option pricing model which includes a time-dependent volatility process. From the perspective of risk management, the extracted risk-neutral densities provide valuable information for value-at-risk estimations. PMID:18249907

  12. Exponential Stability for Stochastic Neural Networks of Neutral Type with Impulsive Effects

    NASA Astrophysics Data System (ADS)

    Sakthivel, Rathinasamy; Samidurai, R.; Anthoni, S. Marshal

    This paper is concerned with the exponential stability of stochastic neural networks of neutral type with impulsive effects. By employing the Lyapunov functional and stochastic analysis, a new stability criterion for the stochastic neural network is derived in terms of linear matrix inequality. A numerical example is provided to show the effectiveness and applicability of the obtained result.

  13. Local Neutral Networks Help Maintain Inaccurately Replicating Ribozymes

    PubMed Central

    Szilágyi, András; Kun, Ádám; Szathmáry, Eörs

    2014-01-01

    The error threshold of replication limits the selectively maintainable genome size against recurrent deleterious mutations for most fitness landscapes. In the context of RNA replication a distinction between the genotypic and the phenotypic error threshold has been made; where the latter concerns the maintenance of secondary structure rather than sequence. RNA secondary structure is treated as a proxy for function. The phenotypic error threshold allows higher per digit mutation rates than its genotypic counterpart, and is known to increase with the frequency of neutral mutations in sequence space. Here we show that the degree of neutrality, i.e. the frequency of nearest-neighbour (one-step) neutral mutants is a remarkably accurate proxy for the overall frequency of such mutants in an experimentally verifiable formula for the phenotypic error threshold; this we achieve by the full numerical solution for the concentration of all sequences in mutation-selection balance up to length 16. We reinforce our previous result that currently known ribozymes could be selectively maintained by the accuracy known from the best available polymerase ribozymes. Furthermore, we show that in silico stabilizing selection can increase the mutational robustness of ribozymes due to the fact that they were produced by artificial directional selection in the first place. Our finding offers a better understanding of the error threshold and provides further insight into the plausibility of an ancient RNA world. PMID:25299454

  14. A semi-free weighting matrices approach for neutral-type delayed neural networks

    NASA Astrophysics Data System (ADS)

    Mai, Huanhuan; Liao, Xiaofeng; Li, Chuandong

    2009-03-01

    In this paper, a new approach is proposed for stability issues of neutral-type neural networks (DNNs) with constant delay. First, the semi-free weighting matrices are proposed and used instead of the known free weighting matrices to express the relationship between the terms in the Leibniz-Newton formula to simplify the system synthesis and to obtain less computation demand. Second, global exponential stability conditions which are less conservative and restrictive than the known results are derived. At the same time, based on the above approach, fewer variable matrices are introduced in the construction of the Lyapunov functional and augmented Lyapunov functional. Two examples are given to show their effectiveness and advantages over others.

  15. Stochastic global exponential stability for neutral-type impulsive neural networks with mixed time-delays and Markovian jumping parameters

    NASA Astrophysics Data System (ADS)

    Bao, Haibo; Cao, Jinde

    2011-09-01

    This paper investigates the problem of the global exponential stability for neutral-type impulsive neural networks with mixed delays and Markovian jumping parameters. The mixed delays include discrete and distributed time-delays and the jumping parameters are generated from a continuous time discrete state homogenous Markov process. Based on the Lyapunov functional, a sufficient criterion is derived in terms of linear matrix equality (LMI).

  16. National negative-ion-based neutral-beam development plan

    SciTech Connect

    Cooper, W.S.; Pyle, R.V.

    1983-08-01

    The plan covers facilities required, program milestones, and decision points. It includes identification of applications, experiments, theoretical research areas, development of specific technologies and reactor development and demonstration facilities required to bring about the successful application of negative-ion-based neutral beams. Particular emphasis is placed on those activities leading to use on existing plasma confinement experiments or their upgrades.

  17. Wastewater neutralization control based in fuzzy logic: Simulation results

    SciTech Connect

    Garrido, R.; Adroer, M.; Poch, M.

    1997-05-01

    Neutralization is a technique widely used as a part of wastewater treatment processes. Due to the importance of this technique, extensive study has been devoted to its control. However, industrial wastewater neutralization control is a procedure with a lot of problems--nonlinearity of the titration curve, variable buffering, changes in loading--and despite the efforts devoted to this subject, the problem has not been totally solved. in this paper, the authors present the development of a controller based in fuzzy logic (FLC). In order to study its effectiveness, it has been compared, by simulation, with other advanced controllers (using identification techniques and adaptive control algorithms using reference models) when faced with various types of wastewater with different buffer capacity or when changes in the concentration of the acid present in the wastewater take place. Results obtained show that FLC could be considered as a powerful alternative for wastewater neutralization processes.

  18. A novel delay-dependent criterion for delayed neural networks of neutral type

    NASA Astrophysics Data System (ADS)

    Lee, S. M.; Kwon, O. M.; Park, Ju H.

    2010-04-01

    This Letter considers a robust stability analysis method for delayed neural networks of neutral type. By constructing a new Lyapunov functional, a novel delay-dependent criterion for the stability is derived in terms of LMIs (linear matrix inequalities). A less conservative stability criterion is derived by using nonlinear properties of the activation function of the neural networks. Two numerical examples are illustrated to show the effectiveness of the proposed method.

  19. Development of a Coxsackievirus A16 neutralization assay based on pseudoviruses for measurement of neutralizing antibody titer in human serum.

    PubMed

    Jin, Jun; Ma, Hongxia; Xu, Lin; An, Dong; Sun, Shiyang; Huang, Xueyong; Kong, Wei; Jiang, Chunlai

    2013-02-01

    Serum neutralizing antibody titers are indicative of protective immunity against Coxsackievirus A16 (CV-A16) and Enterovirus 71 (EV71), the two main etiological agents of hand, foot and mouth disease (HFMD), and provide the basis for evaluating vaccine efficacy. The current CV-A16 neutralization assay based on inhibition of cytopathic effects requires manual microscopic examination, which is time-consuming and labor-intensive. In this study, a high-throughput neutralization assay was developed by employing CV-A16 pseudoviruses expressing luciferase for detecting infectivity in rhabdomyosarcoma (RD) cells and measuring serum viral neutralizing antibodies. Without the need to use infectious CV-A16 strains, the neutralizing antibody titer against CV-A16 could be determined within 15h by measuring luciferase signals by this assay. The pseudovirus CV-A16 neutralization assay (pCNA) was validated by comparison with a conventional CV-A16 neutralization assay (cCNA) in testing 174 human serum samples collected from children (age <5 years). The neutralizing antibody titers determined by these two assays were well correlated (R(2)=0.7689). These results suggest that the pCNA can serve as a rapid and objective procedure for the measurement of neutralizing antibodies against CV-A16. PMID:23178532

  20. An ultrasensitive universal detector based on neutralizer displacement

    NASA Astrophysics Data System (ADS)

    Das, Jagotamoy; Cederquist, Kristin B.; Zaragoza, Alexandre A.; Lee, Paul E.; Sargent, Edward H.; Kelley, Shana O.

    2012-08-01

    Diagnostic technologies that can provide the simultaneous detection of nucleic acids for gene expression, proteins for host response and small molecules for profiling the human metabolome will have a significant advantage in providing comprehensive patient monitoring. Molecular sensors that report changes in the electrostatics of a sensor's surface on analyte binding have shown unprecedented sensitivity in the detection of charged biomolecules, but do not lend themselves to the detection of small molecules, which do not carry significant charge. Here, we introduce the neutralizer displacement assay that allows charge-based sensing to be applied to any class of molecule irrespective of the analyte charge. The neutralizer displacement assay starts with an aptamer probe bound to a neutralizer. When analyte binding occurs the neutralizer is displaced, which results in a dramatic change in the surface charge for all types of analytes. We have tested the sensitivity, speed and specificity of this system in the detection of a panel of molecules: (deoxy)ribonucleic acid, ribonucleic acid, cocaine, adenosine triphosphate and thrombin.

  1. Non-consensus opinion model with a neutral view on complex networks

    NASA Astrophysics Data System (ADS)

    Tian, Zihao; Dong, Gaogao; Du, Ruijin; Ma, Jing

    2016-05-01

    A nonconsensus opinion (NCO) model was introduced recently, which allows the stable coexistence of minority and majority opinions. However, due ​to disparities in the knowledge, experiences, and personality or self-protection of agents, they often remain ​neutral when faced with some opinions in real scenarios. ​To address this issue, we propose a general non-consensus opinion model with neutral view (NCON) ​and we define the dynamic opinion ​change process. We applied the NCON model to different topological networks and studied the formation of opinion clusters. In the case of random graphs, random regular networks, and scale-free (SF) networks, we found that the system moved from a continuous phase transition to a discontinuous phase transition as the connectivity density and exponent of the SF network λ ​decreased and increased in the steady state, respectively. Moreover, the initial proportions of neutral opinions were found to have little effect on the proportional structure of opinions at the steady state. These results suggest that the majority choice between positive and negative opinions depends on the initial proportion of each opinion. The NCON model may have potential applications for decision makers.

  2. Development of neutral atom traps based on a microfabricated waveguide

    NASA Astrophysics Data System (ADS)

    Jau, Yuan-Yu; Lee, Jongmin; Biedermann, Grant; Siddiqui, Aleem; Eichenfield, Matt; Dougla, Erica

    2016-05-01

    Implementation of trapping neutral atoms in the evanescent fields generated by a nano-structure, such as a nanofiber or a microfabricated nano-waveguide, will naturally enable strong atom-photon interactions, which serve the key mechanisms for different type of quantum controls. At Sandia National Labs, we are aiming to develop a platform based on this concept to eventually trap cesium atoms with a microfabricated waveguide. Although, neutral atom traps using optical nanofiber has been demonstrated, there are several key issues that need to be resolved to realize trapping atoms with microfabricated structure. The subjects include the material for making the waveguide, optical power handling capability, surface adsorption of alkali-metal atoms, surface roughness of the nano-structure, cold-atom source for loading the atoms into the evanescent-field traps, etc. We will discuss our studies on these related subjects and report our latest progress.

  3. Neutral Networks for Subpixel Classification of Multispectral Images

    NASA Technical Reports Server (NTRS)

    Figueroa, Ricardo R.; Hunt, Shawn D.

    1998-01-01

    In this work, the implementation and use of AVHRR (Advanced Very High Resolution Radiometer) images for subpixel analysis is studied. The work consists of two parts, the first is making training data, the second is using the training data to design a neural net subpixel analyzer. Most work on subpixel analysis has been done with images with more spectral bands. AVHRR images were chosen because of their easy acquisition, and because the five spectral bands allow investigation into the development of training data. The first step in subpixel analysis is the development of training data. This consists of image to be classified, and the classification of each pixel. In order to do the classification, a high spatial resolution image is typically needed in order to manually create a classified image. It is difficult to have both the image of interest, and a high spatial resolution image of the same area taken at the same time. Thus it was studied whether a subsampled image taken from the image of interest could serve as the training data. Statistical work has been done showing the unusefulness of this approach. In the second part of the analysis, a feedforward neural net was trained and used to classify the AVHRR images. Results of these tests, comparing the neural net with typical statistical based schemes are shown.

  4. Delay-dependent stability of neural networks of neutral type with time delay in the leakage term

    NASA Astrophysics Data System (ADS)

    Li, Xiaodi; Cao, Jinde

    2010-07-01

    This paper studies the global asymptotic stability of neural networks of neutral type with mixed delays. The mixed delays include constant delay in the leakage term (i.e. 'leakage delay'), time-varying delays and continuously distributed delays. Based on the topological degree theory, Lyapunov method and linear matrix inequality (LMI) approach, some sufficient conditions are derived ensuring the existence, uniqueness and global asymptotic stability of the equilibrium point, which are dependent on both the discrete and distributed time delays. These conditions are expressed in terms of LMI and can be easily checked by the MATLAB LMI toolbox. Even if there is no leakage delay, the obtained results are less restrictive than some recent works. It can be applied to neural networks of neutral type with activation functions without assuming their boundedness, monotonicity or differentiability. Moreover, the differentiability of the time-varying delay in the non-neutral term is removed. Finally, two numerical examples are given to show the effectiveness of the proposed method.

  5. Thermal neutral format based on the step technology

    NASA Technical Reports Server (NTRS)

    Almazan, P. Planas; Legal, J. L.

    1995-01-01

    The exchange of models is one of the most serious problems currently encountered in the practice of spacecraft thermal analysis. Essentially, the problem originates in the diversity of computing environments that are used across different sites, and the consequent proliferation of native tool formats. Furthermore, increasing pressure to reduce the development's life cycle time has originated a growing interest in the so-called spacecraft concurrent engineering. In this context, the realization of the interdependencies between different disciplines and the proper communication between them become critical issues. The use of a neutral format represents a step forward in addressing these problems. Such a means of communication is adopted by consensus. A neutral format is not directly tied to any specific tool and it is kept under stringent change control. Currently, most of the groups promoting exchange formats are contributing with their experience to STEP, the Standard for Exchange of Product Model Data, which is being developed under the auspices of the International Standards Organization (ISO 10303). This paper presents the different efforts made in Europe to provide the spacecraft thermal analysis community with a Thermal Neutral Format (TNF) based on STEP. Following an introduction with some background information, the paper presents the characteristics of the STEP standard. Later, the first efforts to produce a STEP Spacecraft Thermal Application Protocol are described. Finally, the paper presents the currently harmonized European activities that follow up and extend earlier work on the area.

  6. General asymmetric neutral networks and structure design by genetic algorithms: A learning rule for temporal patterns

    SciTech Connect

    Bornholdt, S.; Graudenz, D.

    1993-07-01

    A learning algorithm based on genetic algorithms for asymmetric neural networks with an arbitrary structure is presented. It is suited for the learning of temporal patterns and leads to stable neural networks with feedback.

  7. 200-mm-diameter neutral beam source based on inductively coupled plasma etcher and silicon etching

    SciTech Connect

    Kubota, Tomohiro; Nukaga, Osamu; Ueki, Shinji; Sugiyama, Masakazu; Inamoto, Yoshimasa; Ohtake, Hiroto; Samukawa, Seiji

    2010-09-15

    The authors developed a neutral beam source consisting of a 200-mm-diameter inductively coupled plasma etcher and a graphite neutralization aperture plate based on the design of a neutral beam source that Samukawa et al. [Jpn. J. Appl. Phys., Part 2 40, L779 (2001)] developed. They measured flux and energy of neutral particles, ions, and photons using a silicon wafer with a thermocouple and a Faraday cup and calculated the neutralization efficiency. An Ar neutral beam flux of more than 1 mA/cm{sup 2} in equivalent current density and a neutralization efficiency of more than 99% were obtained. The spatial uniformity of the neutral beam flux was within {+-}6% within a 100 mm diameter. Silicon etching using a F{sub 2}-based neutral beam was done at an etch rate of about 47 nm/min, while Cl{sub 2}-based neutral beam realized completely no undercut. The uniformity of etch rate was less than {+-}5% within the area. The etch rate increased by applying bias power to the neutralization aperture plate, which shows that accelerated neutral beam was successfully obtained. These results indicate that the neutral beam source is scalable, making it possible to obtain a large-diameter and uniform neutral beam, which is inevitable for application to mass production.

  8. Optical Frequency Standards Based on Neutral Atoms and Molecules

    NASA Astrophysics Data System (ADS)

    Riehle, Fritz; Helmcke, Juergen

    The current status and prospects of optical frequency standards based on neutral atomic and molecular absorbers are reviewed. Special attention is given to an optical frequency standard based on cold Ca atoms which are interrogated with a pulsed excitation scheme leading to resolved line structures with a quality factor Q > 10^12. The optical frequency was measured by comparison with PTB's primary clock to be νCa = 455 986 240 494.13 kHz with a total relative uncertainty of 2.5 x10^-13. After a recent recommendation of the International Committee of Weights and Measures (CIPM), this frequency standard now represents one of the most accurate realizations of the length unit.

  9. Detection of calcium based neutralizers in milk and milk products by AAS.

    PubMed

    Sowmya, R; Indumathi, K P; Arora, S; Sharma, V; Singh, A K

    2015-02-01

    Current study was carried out with the intent to standardize detection and estimation method for calcium (Ca) based neutralizers in milk and milk based indigenous products (khoa and paneer) using atomic absorption spectroscopy (AAS). Neutralized milk, khoa and paneer samples were prepared using milk with developed acidity to which calculated quantity of neutralizer (Ca based) was added. Rosalic acid test results get masked at times due to developed acidity which neutralizes the alkalinity imparted by neutralizer and hence gives false result with time in neutralizer added samples. Atomic absorption spectroscopy proved to be an accurate estimate which could detect the abnormal rise in mineral concentration even with slight addition of neutralizers in comparison with control milk and milk products. Formalin, which is a commonly used preservative in milk samples for chemical analysis, did not have any significant impact on estimation of calcium in the neutralized milk during storage. PMID:25694738

  10. Network-Based Management Procedures.

    ERIC Educational Resources Information Center

    Buckner, Allen L.

    Network-based management procedures serve as valuable aids in organizational management, achievement of objectives, problem solving, and decisionmaking. Network techniques especially applicable to educational management systems are the program evaluation and review technique (PERT) and the critical path method (CPM). Other network charting…

  11. Manipulating Neutral Atoms in Chip-Based Magnetic Traps

    NASA Technical Reports Server (NTRS)

    Aveline, David; Thompson, Robert; Lundblad, Nathan; Maleki, Lute; Yu, Nan; Kohel, James

    2009-01-01

    Several techniques for manipulating neutral atoms (more precisely, ultracold clouds of neutral atoms) in chip-based magnetic traps and atomic waveguides have been demonstrated. Such traps and waveguides are promising components of future quantum sensors that would offer sensitivities much greater than those of conventional sensors. Potential applications include gyroscopy and basic research in physical phenomena that involve gravitational and/or electromagnetic fields. The developed techniques make it possible to control atoms with greater versatility and dexterity than were previously possible and, hence, can be expected to contribute to the value of chip-based magnetic traps and atomic waveguides. The basic principle of these techniques is to control gradient magnetic fields with suitable timing so as to alter a trap to exert position-, velocity-, and/or time-dependent forces on atoms in the trap to obtain desired effects. The trap magnetic fields are generated by controlled electric currents flowing in both macroscopic off-chip electromagnet coils and microscopic wires on the surface of the chip. The methods are best explained in terms of examples. Rather than simply allowing atoms to expand freely into an atomic waveguide, one can give them a controllable push by switching on an externally generated or a chip-based gradient magnetic field. This push can increase the speed of the atoms, typically from about 5 to about 20 cm/s. Applying a non-linear magnetic-field gradient exerts different forces on atoms in different positions a phenomenon that one can exploit by introducing a delay between releasing atoms into the waveguide and turning on the magnetic field.

  12. Directory Enabled Policy Based Networking

    SciTech Connect

    KELIIAA, CURTIS M.

    2001-10-01

    This report presents a discussion of directory-enabled policy-based networking with an emphasis on its role as the foundation for securely scalable enterprise networks. A directory service provides the object-oriented logical environment for interactive cyber-policy implementation. Cyber-policy implementation includes security, network management, operational process and quality of service policies. The leading network-technology vendors have invested in these technologies for secure universal connectivity that transverses Internet, extranet and intranet boundaries. Industry standards are established that provide the fundamental guidelines for directory deployment scalable to global networks. The integration of policy-based networking with directory-service technologies provides for intelligent management of the enterprise network environment as an end-to-end system of related clients, services and resources. This architecture allows logical policies to protect data, manage security and provision critical network services permitting a proactive defense-in-depth cyber-security posture. Enterprise networking imposes the consideration of supporting multiple computing platforms, sites and business-operation models. An industry-standards based approach combined with principled systems engineering in the deployment of these technologies allows these issues to be successfully addressed. This discussion is focused on a directory-based policy architecture for the heterogeneous enterprise network-computing environment and does not propose specific vendor solutions. This document is written to present practical design methodology and provide an understanding of the risks, complexities and most important, the benefits of directory-enabled policy-based networking.

  13. The CB1 Neutral Antagonist Tetrahydrocannabivarin Reduces Default Mode Network and Increases Executive Control Network Resting State Functional Connectivity in Healthy Volunteers

    PubMed Central

    Rzepa, Ewelina; Tudge, Luke

    2016-01-01

    Background: The cannabinoid cannabinoid type 1 (CB1) neutral antagonist tetrahydrocannabivarin (THCv) has been suggested as a possible treatment for obesity, but without the depressogenic side-effects of inverse antagonists such as Rimonabant. However, how THCv might affect the resting state functional connectivity of the human brain is as yet unknown. Method: We examined the effects of a single 10mg oral dose of THCv and placebo in 20 healthy volunteers in a randomized, within-subject, double-blind design. Using resting state functional magnetic resonance imaging and seed-based connectivity analyses, we selected the amygdala, insula, orbitofrontal cortex, and dorsal medial prefrontal cortex (dmPFC) as regions of interest. Mood and subjective experience were also measured before and after drug administration using self-report scales. Results: Our results revealed, as expected, no significant differences in the subjective experience with a single dose of THCv. However, we found reduced resting state functional connectivity between the amygdala seed region and the default mode network and increased resting state functional connectivity between the amygdala seed region and the dorsal anterior cingulate cortex and between the dmPFC seed region and the inferior frontal gyrus/medial frontal gyrus. We also found a positive correlation under placebo for the amygdala-precuneus connectivity with the body mass index, although this correlation was not apparent under THCv. Conclusion: Our findings are the first to show that treatment with the CB1 neutral antagonist THCv decreases resting state functional connectivity in the default mode network and increases connectivity in the cognitive control network and dorsal visual stream network. This effect profile suggests possible therapeutic activity of THCv for obesity, where functional connectivity has been found to be altered in these regions. PMID:26362774

  14. Negative ion based neutral beam injector for JT-60U

    NASA Astrophysics Data System (ADS)

    Okumura, Y.; Araki, M.; Hanada, M.; Inoue, T.; Kunieda, S.; Kuriyama, M.; Matsuoka, M.; Mizuno, M.; Ohara, Y.; Tanaka, M.; Watanabe, K.

    1992-10-01

    A 500 keV, 10 MW neutral beam injector is to be constructed in JT-60 Upgrade for the experiments of current drive and heating of heat density core plasmas. This is the first neutral beam injector in the world using negative ions as the primary ions. In the design, D- ion beams of 44 A, 500 keV are produced by two ion sources (22 A/each ion source) and neutralized in a long gas neutralizer. The total system efficiency is about 40%. The ion source is a cesium-seeded multicusp volume source having a three stage electrostatic accelerator. To reduce the stripping loss of D- ions in the accelerator, the ion source should be operated at a low pressure of 0.3 Pa with a current density of 13 mA/cm2. The first test of the full-size negative ion source is scheduled from middle of 1993.

  15. Wastewater neutralization control based on fuzzy logic: Experimental results

    SciTech Connect

    Adroer, M.; Alsina, A.; Aumatell, J.; Poch, M.

    1999-07-01

    Many industrial wastes contain acidic or alkaline materials that require neutralization of previous discharge into receiving waters or to chemical and biological treatment plants. The control of the wastewater neutralization process is subjected to several difficulties, such as the highly nonlinear titration curve (with special sensitivity around neutrality), the unknown water composition, the variable buffering capacity of the system, and the changes in input loading. To deal with these problems, this study proposes a fixed fuzzy logic controller (FLC) structure coupled with a tuning factor. The versatility and robustness of this controller has been proved when faced with solutions of variable buffering capacity, with acids that cover a wide pK range and with switches between acids throughout the course of a test. Laboratory experiments and simulation runs using the proposed controller were successful in a wide operational range.

  16. Influence of neutral amine ligands on the network assembly of lead(II) 4-sulfobenzoate complexes

    NASA Astrophysics Data System (ADS)

    Zhang, Li-Ping; Zhu, Long-Guan

    2008-02-01

    Two new lead(II) 4-sulfobenzoate complexes with amine ligands, [Pb(4-sb)(2,2'-bipy)] n ( 1) and {[Pb(4-sb)(4,4'-bipy) 1/2] · (4,4'-bipy) 1/2} n ( 2) (2,2'-bipy = 2,2'-bipyridine; 4,4'-bipy = 4,4'-bipyridine; 4-sb = 4-sulfobenzoate dianion), were synthesized and characterized by single-crystal X-ray analyses, IR, TG, elemental analyses and fluorescent studies. Complexes 1 and 2, in addition to previously reported [Pb(4-sb)(H 2O) 2] n ( 3) and {[Pb(4-sb)(phen)] · (H 2O)} n ( 4) where phen is 1,10-phenanthroline, all contain [Pb(4-sb)] building units, while four [Pb(4-sb)] networks in 1- 4 are very different, which is significantly influenced by the neutral ligands. The coordination array of complex 1 is a 2-D network in which each 4-sb acts as a η 5-μ 3 mode while the complex 2 is a 3-D architecture in which each 4-sb performs a η 5-μ 6 mode. Both coordination modes of 4-sb ligands in 1- 2 are novel and first reported in this paper.

  17. Virus replicon particle based Chikungunya virus neutralization assay using Gaussia luciferase as readout

    PubMed Central

    2013-01-01

    Background Chikungunya virus (CHIKV) has been responsible for large epidemic outbreaks causing fever, headache, rash and severe arthralgia. So far, no specific treatment or vaccine is available. As nucleic acid amplification can only be used during the viremic phase of the disease, serological tests like neutralization assays are necessary for CHIKV diagnosis and for determination of the immune status of a patient. Furthermore, neutralization assays represent a useful tool to validate the efficacy of potential vaccines. As CHIKV is a BSL3 agent, neutralization assays with infectious virus need to be performed under BSL3 conditions. Our aim was to develop a neutralization assay based on non-infectious virus replicon particles (VRPs). Methods VRPs were produced by cotransfecting baby hamster kidney-21 cells with a CHIKV replicon expressing Gaussia luciferase (Gluc) and two helper RNAs expressing the CHIKV capsid protein or the remaining structural proteins, respectively. The resulting single round infectious particles were used in CHIKV neutralization assays using secreted Gluc as readout. Results Upon cotransfection of a CHIKV replicon expressing Gluc and the helper RNAs VRPs could be produced efficiently under optimized conditions at 32°C. Infection with VRPs could be measured via Gluc secreted into the supernatant. The successful use of VRPs in CHIKV neutralization assays was demonstrated using a CHIKV neutralizing monoclonal antibody or sera from CHIKV infected patients. Comparison of VRP based neutralization assays in 24- versus 96-well format using different amounts of VRPs revealed that in the 96-well format a high multiplicity of infection is favored, while in the 24-well format reliable results are also obtained using lower infection rates. Comparison of different readout times revealed that evaluation of the neutralization assay is already possible at the same day of infection. Conclusions A VRP based CHIKV neutralization assay using Gluc as readout

  18. Neutral beamline with ion energy recovery based on magnetic blocking of electrons

    DOEpatents

    Stirling, W.L.

    1980-07-01

    A neutral beamline generator with energy recovery of the full-energy ion component of the beam based on magnetic blocking of electrons is provided. Ions from a positive ion source are accelerated to the desired beam energy from a slightly positive potential level with respect to ground through a neutralizer cell by means of a negative acceleration voltage. The unneutralized full-energy ion component of the beam exiting the neutralizer are retarded and slightly deflected and the elecrons in the neutralizer are blocked by a magnetic field generated transverse to the beamline. An electron collector in the form of a coaxial cylinder surrounding and protruding axial a few centimeters beyond the neutralizer exit terminates the electrons which exit the neutralizer in an E x B drift to the collector when the collector is biased a few hundred volts positive with respect to the neutralizer voltage. The neutralizer is operated at the negative acceleration voltage. The neutralizer is operated at the negative acceleration voltage, and the deflected full energy ions are decelerated and the charge collected at ground potential thereby expending none of their energy received from the acceleration power supply.

  19. Development of a high-throughput β-Gal-based neutralization assay for quantitation of herpes simplex virus-neutralizing antibodies in human samples.

    PubMed

    Baccari, Amy; Cooney, Michael; Blevins, Tamara P; Morrison, Lynda A; Larson, Shane; Skoberne, Mojca; Belshe, Robert B; Flechtner, Jessica B; Long, Deborah

    2016-07-19

    Measurement of neutralizing antibodies against herpes simplex virus (HSV) is important for evaluation of candidate vaccines. The established plaque-reduction neutralization assay is time consuming, labor intensive, and difficult to validate and transfer. Here, we describe the characterization of a HSV-neutralization assay based on the expression of a reporter gene, β-galactosidase (β-Gal). Using previously constructed HSV-β-Gal recombinant viruses, HSV-2/Gal and HSV-1/tk12, we developed a colorimetric β-Gal-based neutralization assay that is sensitive and highly reproducible, and performed in less than 48h. HSV-1 and HSV-2 neutralizing titers measured by the β-Gal-based neutralization assay were equivalent to those obtained by a plaque reduction neutralization assay. Intra- and inter-assay precision studies demonstrated that the β-Gal-based assay was repeatable and yielded low and acceptable variation. In addition, comparison of HSV-2 neutralizing antibody (NAb) titers measured in two independent laboratories by two unique β-Gal-based assays showed a highly significant correlation (r=0.9499, p<0.0001) between the two assays. The new assay will serve as an important tool both for preclinical and clinical trials of new HSV vaccines. PMID:27265458

  20. Dynamic Evolution Model Based on Social Network Services

    NASA Astrophysics Data System (ADS)

    Xiong, Xi; Gou, Zhi-Jian; Zhang, Shi-Bin; Zhao, Wen

    2013-11-01

    Based on the analysis of evolutionary characteristics of public opinion in social networking services (SNS), in the paper we propose a dynamic evolution model, in which opinions are coupled with topology. This model shows the clustering phenomenon of opinions in dynamic network evolution. The simulation results show that the model can fit the data from a social network site. The dynamic evolution of networks accelerates the opinion, separation and aggregation. The scale and the number of clusters are influenced by confidence limit and rewiring probability. Dynamic changes of the topology reduce the number of isolated nodes, while the increased confidence limit allows nodes to communicate more sufficiently. The two effects make the distribution of opinion more neutral. The dynamic evolution of networks generates central clusters with high connectivity and high betweenness, which make it difficult to control public opinions in SNS.

  1. Size-exclusion partitioning of neutral solutes in crosslinked polymer networks: A Monte Carlo simulation study

    SciTech Connect

    Quesada-Pérez, Manuel; Maroto-Centeno, José Alberto; Adroher-Benítez, Irene

    2014-05-28

    In this work, the size-exclusion partitioning of neutral solutes in crosslinked polymer networks has been studied through Monte Carlo simulations. Two models that provide user-friendly expressions to predict the partition coefficient have been tested over a wide range of volume fractions: Ogston's model (especially devised for fibrous media) and the pore model. The effects of crosslinking and bond stiffness have also been analyzed. Our results suggest that the fiber model can acceptably account for size-exclusion effects in crosslinked gels. Its predictions are good for large solutes if the fiber diameter is assumed to be the effective monomer diameter. For solutes sizes comparable to the monomer dimensions, a smaller fiber diameter must be used. Regarding the pore model, the partition coefficient is poorly predicted when the pore diameter is estimated as the distance between adjacent crosslinker molecules. On the other hand, our results prove that the pore sizes obtained from the pore model by fitting partitioning data of swollen gels are overestimated.

  2. Neutral beamline with ion energy recovery based on magnetic blocking of electrons

    DOEpatents

    Stirling, William L.

    1982-01-01

    A neutral beamline generator with energy recovery of the full-energy ion ponent of the beam based on magnetic blocking of electrons is provided. Ions from a positive ion source are accelerated to the desired beam energy from a slightly positive potential level with respect to ground through a neutralizer cell by means of a negative acceleration voltage. The unneutralized full-energy ion component of the beam exiting the neutralizer are retarded and slightly deflected and the electrons in the neutralizer are blocked by a magnetic field generated transverse to the beamline. An electron collector in the form of a coaxial cylinder surrounding and protruding axial a few centimeters beyond the neutralizer exit terminates the electrons which exit the neutralizer in an E x B drift to the collector when the collector is biased a few hundred volts positive with respect to the neutralizer voltage. The neutralizer is operated at the negative acceleration voltage, and the deflected full energy ions are decelerated and the charge collected at ground potential thereby expending none of their energy received from the acceleration power supply.

  3. Pseudotype-Based Neutralization Assays for Influenza: A Systematic Analysis

    PubMed Central

    Carnell, George William; Ferrara, Francesca; Grehan, Keith; Thompson, Craig Peter; Temperton, Nigel James

    2015-01-01

    The use of vaccination against the influenza virus remains the most effective method of mitigating the significant morbidity and mortality caused by this virus. Antibodies elicited by currently licensed influenza vaccines are predominantly hemagglutination-inhibition (HI)-competent antibodies that target the globular head of hemagglutinin (HA) thus inhibiting influenza virus entry into target cells. These antibodies predominantly confer homosubtypic/strain specific protection and only rarely confer heterosubtypic protection. However, recent academia or pharma-led R&D toward the production of a “universal vaccine” has centered on the elicitation of antibodies directed against the stalk of the influenza HA that has been shown to confer broad protection across a range of different subtypes (H1–H16). The accurate and sensitive measurement of antibody responses elicited by these “next-generation” influenza vaccines is, however, hampered by the lack of sensitivity of the traditional influenza serological assays HI, single radial hemolysis, and microneutralization. Assays utilizing pseudotypes, chimeric viruses bearing influenza glycoproteins, have been shown to be highly efficient for the measurement of homosubtypic and heterosubtypic broadly neutralizing antibodies, making them ideal serological tools for the study of cross-protective responses against multiple influenza subtypes with pandemic potential. In this review, we will analyze and compare literature involving the production of influenza pseudotypes with particular emphasis on their use in serum antibody neutralization assays. This will enable us to establish the parameters required for optimization and propose a consensus protocol to be employed for the further deployment of these assays in influenza vaccine immunogenicity studies. PMID:25972865

  4. Host Event Based Network Monitoring

    SciTech Connect

    Jonathan Chugg

    2013-01-01

    The purpose of INL’s research on this project is to demonstrate the feasibility of a host event based network monitoring tool and the effects on host performance. Current host based network monitoring tools work on polling which can miss activity if it occurs between polls. Instead of polling, a tool could be developed that makes use of event APIs in the operating system to receive asynchronous notifications of network activity. Analysis and logging of these events will allow the tool to construct the complete real-time and historical network configuration of the host while the tool is running. This research focused on three major operating systems commonly used by SCADA systems: Linux, WindowsXP, and Windows7. Windows 7 offers two paths that have minimal impact on the system and should be seriously considered. First is the new Windows Event Logging API, and, second, Windows 7 offers the ALE API within WFP. Any future work should focus on these methods.

  5. Ta2O5-based redox memory formed by neutral beam oxidation

    NASA Astrophysics Data System (ADS)

    Ohno, Takeo; Samukawa, Seiji

    2016-06-01

    A room temperature neutral beam oxidation process using a tantalum (Ta) metal film was used to obtain a high quality Ta oxide (Ta2O5) film. After irradiation of a Ta metal film with a neutral oxygen beam, a nanometer-thick Ta2O5 film with a film density of 7.5 g/cm3 was obtained. We also confirmed that the fabricated Cu/Ta2O5/Pt redox memory structure shows a bipolar resistive switching characteristic. This result demonstrates the great potential of neutral beam metal oxidation for the development of redox-based memory devices.

  6. Network fingerprint: a knowledge-based characterization of biomedical networks

    PubMed Central

    Cui, Xiuliang; He, Haochen; He, Fuchu; Wang, Shengqi; Li, Fei; Bo, Xiaochen

    2015-01-01

    It can be difficult for biomedical researchers to understand complex molecular networks due to their unfamiliarity with the mathematical concepts employed. To represent molecular networks with clear meanings and familiar forms for biomedical researchers, we introduce a knowledge-based computational framework to decipher biomedical networks by making systematic comparisons to well-studied “basic networks”. A biomedical network is characterized as a spectrum-like vector called “network fingerprint”, which contains similarities to basic networks. This knowledge-based multidimensional characterization provides a more intuitive way to decipher molecular networks, especially for large-scale network comparisons and clustering analyses. As an example, we extracted network fingerprints of 44 disease networks in the Kyoto Encyclopedia of Genes and Genomes (KEGG) database. The comparisons among the network fingerprints of disease networks revealed informative disease-disease and disease-signaling pathway associations, illustrating that the network fingerprinting framework will lead to new approaches for better understanding of biomedical networks. PMID:26307246

  7. Towards a lattice based neutral magnesium optical frequency standard

    NASA Astrophysics Data System (ADS)

    Kelkar, Hrishikesh; Riedmann, Matthias; Wuebbena, Temmo; Kulosa, Andre; Friebe, Jan; Pape, Andre; Amairi, Sana; Malobabic, Sina; Zipfel, Klaus; Ruehmann, Steffen; -Maria Rasel, Ernst; Ertmer, Wolfgang

    2010-03-01

    Magnesium is a promising candidate for a high performance neutral atom optical frequency standard. It offers a low sensitivity to frequency shifts of the ^1S0-^3P0 clock transition by room temperature blackbody radiation and has several isotopes of suitable abundance (two bosonic, one fermionic) to realize an optical clock. We report on recent progress towards creating a lattice clock of magnesium. ^24Mg atoms are pre-cooled in two stages. The singlet Magneto Optical Trap (MOT) captures and cools atoms from an atomic beam which are then loaded into a triplet MOT. The triplet MOT has a decay channel to the dark ^3P0 state which is used to load atoms into a 1064 nm dipole trap. The cooling stages are on simultaneously and atoms are continuously loaded in the dipole trap. We capture upto 9 10^4 atoms at a temperature below 100 μK. We are exploring different avenues for further cooling which will enable reaching the Lamb-Dicke regime in a magic wavelength lattice.

  8. On Tree-Based Phylogenetic Networks.

    PubMed

    Zhang, Louxin

    2016-07-01

    A large class of phylogenetic networks can be obtained from trees by the addition of horizontal edges between the tree edges. These networks are called tree-based networks. We present a simple necessary and sufficient condition for tree-based networks and prove that a universal tree-based network exists for any number of taxa that contains as its base every phylogenetic tree on the same set of taxa. This answers two problems posted by Francis and Steel recently. A byproduct is a computer program for generating random binary phylogenetic networks under the uniform distribution model. PMID:27228397

  9. Location-Based Services in Vehicular Networks

    ERIC Educational Resources Information Center

    Wu, Di

    2013-01-01

    Location-based services have been identified as a promising communication paradigm in highly mobile and dynamic vehicular networks. However, existing mobile ad hoc networking cannot be directly applied to vehicular networking due to differences in traffic conditions, mobility models and network topologies. On the other hand, hybrid architectures…

  10. A delay-dependent approach to robust control for neutral uncertain neural networks with mixed interval time-varying delays

    NASA Astrophysics Data System (ADS)

    Lu, Chien-Yu

    2011-04-01

    This paper considers the problem of delay-dependent global robust stabilization for discrete, distributed and neutral interval time-varying delayed neural networks described by nonlinear delay differential equations of the neutral type. The parameter uncertainties are norm bounded. The activation functions are assumed to be bounded and globally Lipschitz continuous. Using a Lyapunov functional approach and linear matrix inequality (LMI) techniques, the stability criteria for the uncertain neutral neural networks with interval time-varying delays are established in the form of LMIs, which can be readily verified using the standard numerical software. An important feature of the result reported is that all the stability conditions are dependent on the upper and lower bounds of the delays. Another feature of the results lies in that it involves fewer free weighting matrix strategy, and upper bounds of the inner product between two vectors are not introduced to reduce the conservatism of the criteria. Two illustrative examples are provided to demonstrate the effectiveness and the reduced conservatism of the proposed method.

  11. Knowledge-Based Network Operations

    NASA Astrophysics Data System (ADS)

    Wu, Chuan-lin; Hung, Chaw-Kwei; Stedry, Steven P.; McClure, James P.; Yeh, Show-Way

    1988-03-01

    An expert system is being implemented for enhancing operability of the Ground Communication Facility (GCF) of Jet Propulsion Laboratory's (JPL) Deep Space Network (DSN). The DSN is a tracking network for all of JPL's spacecraft plus a subset of spacecrafts launched by other NASA centers. A GCF upgrade task is set to replace the current GCF aging system with new, modern equipments which are capable of using knowledge-based monitor and control approach. The expert system, implemented in terms of KEE and SUN workstation, is used for performing network fault management, configuration management, and performance management in real-time. Monitor data are collected from each processor and DSCC's in every five seconds. In addition to serving as input parameters of the expert system, extracted management information is used to update a management information database. For the monitor and control purpose, software of each processor is divided into layers following the OSI standard. Each layer is modeled as a finite state machine. A System Management Application Process (SMAP) is implemented at application layer, which coordinates layer managers of the same processor and communicates with peer SMAPs of other processors. The expert system will be tuned by augmenting the production rules as the operation is going on, and its performance will be measured.

  12. NEP: web server for epitope prediction based on antibody neutralization of viral strains with diverse sequences.

    PubMed

    Chuang, Gwo-Yu; Liou, David; Kwong, Peter D; Georgiev, Ivelin S

    2014-07-01

    Delineation of the antigenic site, or epitope, recognized by an antibody can provide clues about functional vulnerabilities and resistance mechanisms, and can therefore guide antibody optimization and epitope-based vaccine design. Previously, we developed an algorithm for antibody-epitope prediction based on antibody neutralization of viral strains with diverse sequences and validated the algorithm on a set of broadly neutralizing HIV-1 antibodies. Here we describe the implementation of this algorithm, NEP (Neutralization-based Epitope Prediction), as a web-based server. The users must supply as input: (i) an alignment of antigen sequences of diverse viral strains; (ii) neutralization data for the antibody of interest against the same set of antigen sequences; and (iii) (optional) a structure of the unbound antigen, for enhanced prediction accuracy. The prediction results can be downloaded or viewed interactively on the antigen structure (if supplied) from the web browser using a JSmol applet. Since neutralization experiments are typically performed as one of the first steps in the characterization of an antibody to determine its breadth and potency, the NEP server can be used to predict antibody-epitope information at no additional experimental costs. NEP can be accessed on the internet at http://exon.niaid.nih.gov/nep. PMID:24782517

  13. EPA (ENVIRONMENTAL PROTECTION AGENCY) METHOD STUDY 30, METHOD 625 - BASE/NEUTRALS, ACIDS AND PESTICIDES

    EPA Science Inventory

    The work which is described in this report was performed for the purpose of validating, through an interlaboratory study, Method 625 for the analysis of the base/neutral, acid, and pesticide priority pollutants. This method is based on the extraction and concentration of the vari...

  14. Unravelling the Ru-Catalyzed Hydrogenolysis of Biomass-Based Polyols under Neutral and Acidic Conditions.

    PubMed

    Hausoul, Peter J C; Negahdar, Leila; Schute, Kai; Palkovits, Regina

    2015-10-12

    The aqueous Ru/C-catalyzed hydrogenolysis of biomass-based polyols such as erythritol, xylitol, sorbitol, and cellobitol is studied under neutral and acidic conditions. For the first time, the complete product spectrum of C2 C6 polyols is identified and, based on a thorough analysis of the reaction mixtures, a comprehensive reaction mechanism is proposed, which consists of (de)hydrogenation, epimerization, decarbonylation, and deoxygenation reactions. The data reveal that the Ru-catalyzed deoxygenation reaction is highly selective for the cleavage of terminal hydroxyl groups. Changing from neutral to acidic conditions suppresses decarbonylation, consequently increasing the selectivity towards deoxygenation. PMID:26448526

  15. Block-based neural networks.

    PubMed

    Moon, S W; Kong, S G

    2001-01-01

    This paper presents a novel block-based neural network (BBNN) model and the optimization of its structure and weights based on a genetic algorithm. The architecture of the BBNN consists of a 2D array of fundamental blocks with four variable input/output nodes and connection weights. Each block can have one of four different internal configurations depending on the structure settings, The BBNN model includes some restrictions such as 2D array and integer weights in order to allow easier implementation with reconfigurable hardware such as field programmable logic arrays (FPGA). The structure and weights of the BBNN are encoded with bit strings which correspond to the configuration bits of FPGA. The configuration bits are optimized globally using a genetic algorithm with 2D encoding and modified genetic operators. Simulations show that the optimized BBNN can solve engineering problems such as pattern classification and mobile robot control. PMID:18244385

  16. Delay-dependent exponential stability for uncertain neutral stochastic neural networks with interval time-varying delay

    NASA Astrophysics Data System (ADS)

    Chen, Huabin; Zhao, Yang

    2015-10-01

    This paper is mainly concerned with the problem for the robustly exponential stability in mean square moment of uncertain neutral stochastic neural networks with interval time-varying delay. With an appropriate augmented Lyapunov-Krasovskii functional (LKF) formulated, the convex combination method is utilised to estimate the derivative of the LKF. Some new delay-dependent exponential stability criteria for such systems are obtained in terms of linear matrix inequalities, which involve fewer matrix variables and have less conservatism. Finally, two illustrative numerical examples are given to show the effectiveness of our obtained results.

  17. ALCBEAM - Neutral beam formation and propagation code for beam-based plasma diagnostics

    NASA Astrophysics Data System (ADS)

    Bespamyatnov, I. O.; Rowan, W. L.; Liao, K. T.

    2012-03-01

    ALCBEAM is a new three-dimensional neutral beam formation and propagation code. It was developed to support the beam-based diagnostics installed on the Alcator C-Mod tokamak. The purpose of the code is to provide reliable estimates of the local beam equilibrium parameters: such as beam energy fractions, density profiles and excitation populations. The code effectively unifies the ion beam formation, extraction and neutralization processes with beam attenuation and excitation in plasma and neutral gas and beam stopping by the beam apertures. This paper describes the physical processes interpreted and utilized by the code, along with exploited computational methods. The description is concluded by an example simulation of beam penetration into plasma of Alcator C-Mod. The code is successfully being used in Alcator C-Mod tokamak and expected to be valuable in the support of beam-based diagnostics in most other tokamak environments. Program summaryProgram title: ALCBEAM Catalogue identifier: AEKU_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEKU_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 66 459 No. of bytes in distributed program, including test data, etc.: 7 841 051 Distribution format: tar.gz Programming language: IDL Computer: Workstation, PC Operating system: Linux RAM: 1 GB Classification: 19.2 Nature of problem: Neutral beams are commonly used to heat and/or diagnose high-temperature magnetically-confined laboratory plasmas. An accurate neutral beam characterization is required for beam-based measurements of plasma properties. Beam parameters such as density distribution, energy composition, and atomic excited populations of the beam atoms need to be known. Solution method: A neutral beam is initially formed as an ion beam which is extracted from

  18. A Network Coding Based Routing Protocol for Underwater Sensor Networks

    PubMed Central

    Wu, Huayang; Chen, Min; Guan, Xin

    2012-01-01

    Due to the particularities of the underwater environment, some negative factors will seriously interfere with data transmission rates, reliability of data communication, communication range, and network throughput and energy consumption of underwater sensor networks (UWSNs). Thus, full consideration of node energy savings, while maintaining a quick, correct and effective data transmission, extending the network life cycle are essential when routing protocols for underwater sensor networks are studied. In this paper, we have proposed a novel routing algorithm for UWSNs. To increase energy consumption efficiency and extend network lifetime, we propose a time-slot based routing algorithm (TSR).We designed a probability balanced mechanism and applied it to TSR. The theory of network coding is introduced to TSBR to meet the requirement of further reducing node energy consumption and extending network lifetime. Hence, time-slot based balanced network coding (TSBNC) comes into being. We evaluated the proposed time-slot based balancing routing algorithm and compared it with other classical underwater routing protocols. The simulation results show that the proposed protocol can reduce the probability of node conflicts, shorten the process of routing construction, balance energy consumption of each node and effectively prolong the network lifetime. PMID:22666045

  19. Ground-based observations of ion/neutral coupling at Thule and Qanaq, Greenland

    NASA Technical Reports Server (NTRS)

    Thayer, J. P.; Crowley, G.; Niciejewski, R. J.; Killeen, T. L.; Buchau, J.; Reinisch, B. W.

    1995-01-01

    During December 1988, 24 hours of darkness and clear sky conditions permitted continuous observations of the O I(6300 A) airglow by a Fabry-Perot interferometer located at Thule Air Base, Greenland. Thus a continuous record of the F region neutral winds was obtained for that month. During this same time period, a digital ionosonde located at Qanaq, Greenland (110 km north of Thule Air Base), was in operation measuring electron density profiles and F region ion drifts. This combination of ground-based observations allowed the investigation of ion/neutral coupling at a temporal resolution of about 15 min. Interplanetary magnetic field (IMF) data from the IMP 8 satellite were also available from December 16 to 24 and indicated intervals of B(sub z) northward IMF conditions during this period. Here we investigate the observed response of the neutral wind to convection changes in the ion drift inside the polar cap for southward and northward IMF B(sub z) conditions. In particular, we establish a control day illustrating the typical antisunward neutral wind and ion drift patterns observed for southward B(sub z) over Thule and Qanaq, and we compare it with observations made when the IMF B(sub z) is directed northward. The observations during periods of northward B(sub z) display sunward directed ion drifts over the polar cap accompanied by decreasing antisunward directed neutral winds. We investigate these times of northward B(sub z) further and demonstrate that the ion drag term alone cannot describe the observed response in the neutral wind during northward IMF.

  20. State estimation for neural neutral-type networks with mixed time-varying delays and Markovian jumping parameters

    NASA Astrophysics Data System (ADS)

    Lakshmanan, S.; Ju, H. Park; Y. Jung, H.; Balasubramaniam, P.

    2012-10-01

    This paper is concerned with a delay-dependent state estimator for neutral-type neural networks with mixed time-varying delays and Markovian jumping parameters. The addressed neural networks have a finite number of modes, and the modes may jump from one to another according to a Markov process. By construction of a suitable Lyapunov—Krasovskii functional, a delay-dependent condition is developed to estimate the neuron states through available output measurements such that the estimation error system is globally asymptotically stable in a mean square. The criterion is formulated in terms of a set of linear matrix inequalities (LMIs), which can be checked efficiently by use of some standard numerical packages.

  1. Delay-dependent passivity criteria for uncertain switched neural networks of neutral type with interval time-varying delay

    NASA Astrophysics Data System (ADS)

    Nagamani, G.; Balasubramaniam, P.

    2012-04-01

    This paper is concerned with the robust passivity analysis of uncertain switched neural networks of neutral type with interval time-varying delay. We first discuss the passivity conditions for the addressed model with norm bounded uncertainties and then extend this result to the case of interval uncertainties. For the neural networks under study, a generalized activation function is considered, where the traditional assumptions on the boundedness, monotonicity and differentiability of the activation functions are removed. Constructing a new Lyapunov-Krasovskii functional with triple integral terms and using a minimal number of free-weighting matrices, some passivity criteria are proposed in terms of linear matrix inequalities, which are dependent on the size of the time delay. Finally, some numerical examples are given to illustrate the effectiveness and merits of the developed techniques.

  2. Passivity analysis for neural networks of neutral type with Markovian jumping parameters and time delay in the leakage term

    NASA Astrophysics Data System (ADS)

    Balasubramaniam, P.; Nagamani, G.; Rakkiyappan, R.

    2011-11-01

    In this paper, the problem of passivity analysis is investigated for neutral type neural networks with Markovian jumping parameters and time delay in the leakage term. The delay is assumed to be time-varying and belong to a given interval, which means that the lower and upper bounds of interval time-varying delays are available. By constructing proper Lyapunov-Krasovskii functional, new delay-dependent passivity conditions are derived in terms of linear matrix inequalities (LMIs). Moreover, it is well known that the passivity behavior of neural networks is very sensitive to the time delay in the leakage term. Finally, three numerical examples are given to show the effectiveness and less conservatism of the proposed method.

  3. Stating the Obvious: The European Qualifications Framework is "Not" a Neutral Evidence-Based Policy Tool

    ERIC Educational Resources Information Center

    Cort, Pia

    2010-01-01

    In European Union policy documents, the European Qualifications Framework (EQF) is described as a neutral tool embedded in an evidence-based policy process. Its purpose is to improve the transparency, comparability and portability of qualifications in the European Union. The aim of this article is to denaturalise the EQF discourse through a…

  4. SHORT-TERM CHANGES IN THE BASE NEUTRALIZING CAPACITY OF AN ACID ADIRONDACK LAKE, NEW YORK

    EPA Science Inventory

    Concern and controversy over the effects of acidic deposition on low ionic strength surface wa ters has led to much discussion on the nature and extent of proton transformations within acid sensitive ecosystems. The source of base neutralizing capacity(BNC) within acid surface wa...

  5. Biogeographic patterns in ocean microbes emerge in a neutral agent-based model.

    PubMed

    Hellweger, Ferdi L; van Sebille, Erik; Fredrick, Neil D

    2014-09-12

    A key question in ecology and evolution is the relative role of natural selection and neutral evolution in producing biogeographic patterns. We quantify the role of neutral processes by simulating division, mutation, and death of 100,000 individual marine bacteria cells with full 1 million-base-pair genomes in a global surface ocean circulation model. The model is run for up to 100,000 years and output is analyzed using BLAST (Basic Local Alignment Search Tool) alignment and metagenomics fragment recruitment. Simulations show the production and maintenance of biogeographic patterns, characterized by distinct provinces subject to mixing and periodic takeovers by neighbors (coalescence), after which neutral evolution reestablishes the province and the patterns reorganize. The emergent patterns are substantial (e.g., down to 99.5% DNA identity between North and Central Pacific provinces) and suggest that microbes evolve faster than ocean currents can disperse them. This approach can also be used to explore environmental selection. PMID:25214628

  6. Computer-Based Information Networks: Selected Examples.

    ERIC Educational Resources Information Center

    Hardesty, Larry

    The history, purpose, and operation of six computer-based information networks are described in general and nontechnical terms. In the introduction the many definitions of an information network are explored. Ohio College Library Center's network (OCLC) is the first example. OCLC began in 1963, and since early 1973 has been extending its services…

  7. Evolution of RNA-Based Networks.

    PubMed

    Stadler, Peter F

    2016-01-01

    RNA molecules have served for decades as a paradigmatic example of molecular evolution that is tractable both in in vitro experiments and in detailed computer simulation. The adaptation of RNA sequences to external selection pressures is well studied and well understood. The de novo innovation or optimization of RNA aptamers and riboswitches in SELEX experiments serves as a case in point. Likewise, fitness landscapes building upon the efficiently computable RNA secondary structures have been a key toward understanding realistic fitness landscapes. Much less is known, however, on models in which multiple RNAs interact with each other, thus actively influencing the selection pressures acting on them. From a computational perspective, RNA-RNA interactions can be dealt with by same basic methods as the folding of a single RNA molecule, although many details become more complicated. RNA-RNA interactions are frequently employed in cellular regulation networks, e.g., as miRNA bases mRNA silencing or in the modulation of bacterial mRNAs by small, often highly structured sRNAs. In this chapter, we summarize the key features of networks of replicators. We highlight the differences between quasispecies-like models describing templates copied by an external replicase and hypercycle similar to autocatalytic replicators. Two aspects are of importance: the dynamics of selection within a population, usually described by conventional dynamical systems, and the evolution of replicating species in the space of chemical types. Product inhibition plays a key role in modulating selection dynamics from survival of the fittest to extinction of unfittest. The sequence evolution of replicators is rather well understood as approximate optimization in a fitness landscape for templates that is shaped by the sequence-structure map of RNA. Some of the properties of this map, in particular shape space covering and extensive neutral networks, give rise to evolutionary patterns such as drift

  8. ANALYTIC MODEL OF THE IBEX RIBBON WITH NEUTRAL SOLAR WIND BASED ION PICKUP BEYOND THE HELIOPAUSE

    SciTech Connect

    Moebius, E.; Liu, K.; Funsten, H.; Gary, S. P.; Winske, D.

    2013-04-01

    Energetic neutral atom (ENA) full sky maps obtained with the Interstellar Boundary Explorer revealed a surprising narrow band of increased intensity, the Ribbon, which has been attributed to the ordering effect of the interstellar magnetic field immediately outside the heliosphere. Among models to explain the enhanced ENA Ribbon intensity, Heerikhuisen et al. base theirs on neutral solar wind origin. It reflects the Ribbon angular and energy distribution correctly, but experiences inherent challenges from the long-term stability of the pickup ion (PUI) ring in velocity space, required for the observed ENA fluxes, and from time variations observed after less than one year due to the long integration length. We provide a simplified analytic model of the neutral solar wind, PUI production beyond the heliopause, and subsequent ENA production. We include convection of the PUIs with the interstellar flow toward the heliopause perpendicular to the interstellar magnetic field, thus far not in any model, extinction of the outward propagating neutral solar wind, and of the PUIs and ENAs on their way inward. Based on hybrid simulations of PUI driven instabilities, with injection rates from this model, scattering and isotropization of the PUIs is noticeably weaker than previously thought, yet too fast for ENA production. Assuming a narrow PUI velocity ring, we find a strong concentration of the ENA origin just outside the heliopause and Ribbon intensities comparable with the observations. Conversely, an isotropic PUI distribution produces ENA fluxes factor of ten too low, thus reemphasizing the need of very slow scattering.

  9. Eliciting neutralizing antibodies with gp120 outer domain constructs based on M-group consensus sequence.

    PubMed

    Qin, Yali; Banasik, Marisa; Kim, SoonJeung; Penn-Nicholson, Adam; Habte, Habtom H; LaBranche, Celia; Montefiori, David C; Wang, Chong; Cho, Michael W

    2014-08-01

    One strategy being evaluated for HIV-1 vaccine development is focusing immune responses towards neutralizing epitopes on the gp120 outer domain (OD) by removing the immunodominant, but non-neutralizing, inner domain. Previous OD constructs have not elicited strong neutralizing antibodies (nAbs). We constructed two immunogens, a monomeric gp120-OD and a trimeric gp120-OD×3, based on an M group consensus sequence (MCON6). Their biochemical and immunological properties were compared with intact gp120. Results indicated better preservation of critical neutralizing epitopes on gp120-OD×3. In contrast to previous studies, our immunogens induced potent, cross-reactive nAbs in rabbits. Although nAbs primarily targeted Tier 1 viruses, they exhibited significant breadth. Epitope mapping analyses indicated that nAbs primarily targeted conserved V3 loop elements. Although the potency and breadth of nAbs were similar for all three immunogens, nAb induction kinetics indicated that gp120-OD×3 was superior to gp120-OD, suggesting that gp120-OD×3 is a promising prototype for further gp120 OD-based immunogen development. PMID:25046154

  10. Eliciting Neutralizing Antibodies with gp120 Outer Domain Constructs Based on M-Group Consensus Sequence

    PubMed Central

    Qin, Yali; Banasik, Marisa; Kim, SoonJeung; Penn-Nicholson, Adam; Habte, Habtom H; Labranche, Celia; Montefiori, David C; Wang, Chong; Cho, Michael W

    2014-01-01

    One strategy being evaluated for HIV-1 vaccine development is focusing immune responses towards neutralizing epitopes on the gp120 outer domain (OD) by removing the immunodominant, but non-neutralizing, inner domain. Previous OD constructs have not elicited strong neutralizing antibodies (nAbs). We constructed two immunogens, a monomeric gp120-OD and a trimeric gp120-OD×3, based on an M group consensus sequence (MCON6). Their biochemical and immunological properties were compared with intact gp120. Results indicated better preservation of critical neutralizing epitopes on gp120-OD×3. In contrast to previous studies, our immunogens induced potent, cross-reactive nAbs in rabbits. Although nAbs primarily targeted Tier 1 viruses, they exhibited significant breadth. Epitope mapping analyses indicated that nAbs primarily targeted conserved V3 loop elements. Although the potency and breadth of nAbs were similar for all three immunogens, nAb induction kinetics indicated that gp120-OD×3 was superior to gp120-OD, suggesting that gp120-OD×3 is a promising prototype for further gp120 OD-based immunogen development. PMID:25046154

  11. Network Medicine: A Network-based Approach to Human Diseases

    NASA Astrophysics Data System (ADS)

    Ghiassian, Susan Dina

    With the availability of large-scale data, it is now possible to systematically study the underlying interaction maps of many complex systems in multiple disciplines. Statistical physics has a long and successful history in modeling and characterizing systems with a large number of interacting individuals. Indeed, numerous approaches that were first developed in the context of statistical physics, such as the notion of random walks and diffusion processes, have been applied successfully to study and characterize complex systems in the context of network science. Based on these tools, network science has made important contributions to our understanding of many real-world, self-organizing systems, for example in computer science, sociology and economics. Biological systems are no exception. Indeed, recent studies reflect the necessity of applying statistical and network-based approaches in order to understand complex biological systems, such as cells. In these approaches, a cell is viewed as a complex network consisting of interactions among cellular components, such as genes and proteins. Given the cellular network as a platform, machinery, functionality and failure of a cell can be studied with network-based approaches, a field known as systems biology. Here, we apply network-based approaches to explore human diseases and their associated genes within the cellular network. This dissertation is divided in three parts: (i) A systematic analysis of the connectivity patterns among disease proteins within the cellular network. The quantification of these patterns inspires the design of an algorithm which predicts a disease-specific subnetwork containing yet unknown disease associated proteins. (ii) We apply the introduced algorithm to explore the common underlying mechanism of many complex diseases. We detect a subnetwork from which inflammatory processes initiate and result in many autoimmune diseases. (iii) The last chapter of this dissertation describes the

  12. Reputation-based collaborative network biology.

    PubMed

    Binder, Jean; Boue, Stephanie; Di Fabio, Anselmo; Fields, R Brett; Hayes, William; Hoeng, Julia; Park, Jennifer S; Peitsch, Manuel C

    2015-01-01

    A pilot reputation-based collaborative network biology platform, Bionet, was developed for use in the sbv IMPROVER Network Verification Challenge to verify and enhance previously developed networks describing key aspects of lung biology. Bionet was successful in capturing a more comprehensive view of the biology associated with each network using the collective intelligence and knowledge of the crowd. One key learning point from the pilot was that using a standardized biological knowledge representation language such as BEL is critical to the success of a collaborative network biology platform. Overall, Bionet demonstrated that this approach to collaborative network biology is highly viable. Improving this platform for de novo creation of biological networks and network curation with the suggested enhancements for scalability will serve both academic and industry systems biology communities. PMID:25592588

  13. A University-Based Electronic Publishing Network.

    ERIC Educational Resources Information Center

    Yavarkovsky, Jerome

    1990-01-01

    Based on a presentation at the Coalition for Networked Information (CNI), this article discusses a university-based computer network that would support electronic publishing. Highlights include the influence on libraries and librarians; technical and operational standards; economic factors; and institutional planning. Six sidebars address other…

  14. Content-Based Networking: DTN, AMS, Sharednet

    NASA Technical Reports Server (NTRS)

    Burleigh, Scott

    2006-01-01

    A detailed viewgraph presentation on DTN, AMS, and Sharednet content-based networking is shown. The contents include: 1) DARPA Content-Based Networking Summary of Requirements; 2) Concept; 3) Key Features of AMS; 4) Overview of Sharednet; 5) SharedNet Deployment History; 6) SharedNet AMS DTN; 7) Detailed Structure; and 8) Bottom line.

  15. Delay-dependent exponential state estimators for stochastic neural networks of neutral type with both discrete and distributed delays

    NASA Astrophysics Data System (ADS)

    Wang, Tong; Ding, Yongsheng; Zhang, Lei; Hao, Kuangrong

    2015-03-01

    This paper considered the state estimation for stochastic neural networks of neutral type with discrete and distributed delays. By using available output measurements, the state estimator can approximate the neuron states, and the asymptotic property of the state error is mean square exponential stable and also almost surely exponential stable in the presence of discrete and distributed delays. Under the Lipschitz assumptions for the activation functions and the measurement nonlinearity, a delay-dependent linear matrix inequality (LMI) criterion is proposed to guarantee the existence of the desired estimators by constructing an appropriate Lyapunov-Krasovskii function. It is shown that the existence conditions and the explicit expression of the state estimator can be parameterised in terms of the solution to a LMI. Finally, two numerical examples are presented to demonstrate the validity of the theoretical results and show that the theorem can provide less conservative conditions.

  16. Rise of the Digitized Public Intellectual: Death of the Professor in the Network Neutral Internet Age

    ERIC Educational Resources Information Center

    Lange, Joshua

    2015-01-01

    The centralised discourse claiming ownership of "knowledge" and "higher education" seems to be declining as the decentralising discourse extolling open source software and informal social network communication are emerging: yet the two are complementary when higher education is seen as a commodity. Thus, in the internet age of…

  17. Identification and classification of galaxies using a biologically-inspired neutral network

    NASA Astrophysics Data System (ADS)

    Somanah, Radhakhrishna; Rughooputh, Soonil D. D. V.; Rughooputh, Harry C. S.

    2002-10-01

    Recognition/Classification of galaxies is an important issue in the large-scale study of the Universe; it is not a simple task. According to estimates computed from the Hubble Deep Field (HDF), astronomers predict that the universe may potentially contain over 100 billion galaxies. Several techniques have been reported for the classification of galaxies. Parallel developments in the field of neural networks have come to a stage that they can participate well in the recognition of objects. Recently, the Pulse-Coupled Neural Network (PCNN) has been shown to be useful for image pre-processing. In this paper, we present a novel way to identify optical galaxies by presenting the images of the galaxies to a hierarchical neural network involving two PCNNs. The image is presented to the network to generate binary barcodes (one per iteration) of the galaxies; the barcodes are unique to the input galactic image. In the current study, we exploit this property to identify optical galaxies by comparing the signatures (binary barcode) from a corresponding database.

  18. Low molecular weight Neutral Boron Dipyrromethene (Bodipy) dyads for fluorescence-based neural imaging

    NASA Astrophysics Data System (ADS)

    Bai, Dan; Benniston, Andrew C.; Clift, Sophie; Baisch, Ulrich; Steyn, Jannetta; Everitt, Nicola; Andras, Peter

    2014-05-01

    The neutral low molecular weight julolidine-based borondipyrromethene (Bodipy) dyads JULBD and MJULBD were used for fast voltage-sensitive dye imaging of neurons in the crab stomatogastric ganglion. The fluorescence modulation of the dyads mirrors alterations in the membrane potential of the imaged neurons. The toxicity of the dyes towards the neurons is related to their structure in that methyl groups at the 3,5 positions results in reduced toxic effects.

  19. Modelling neutral beams in fusion devices: Beamlet-based model for fast particle simulations

    NASA Astrophysics Data System (ADS)

    Asunta, O.; Govenius, J.; Budny, R.; Gorelenkova, M.; Tardini, G.; Kurki-Suonio, T.; Salmi, A.; Sipilä, S.

    2015-03-01

    Neutral beam injection (NBI) will be one of the main sources of heating and non-inductive current drive in ITER. Due to high level of injected power the beam induced heat loads present a potential threat to the integrity of the first wall of the device, particularly in the presence of non-axisymmetric perturbations of the magnetic field. Neutral beam injection can also destabilize Alfvén eigenmodes and energetic particle modes, and act as a source of plasma rotation. Therefore, reliable and accurate simulation of NBI is important for making predictions for ITER, as well as for any other current or future fusion device. This paper introduces a new beamlet-based neutral beam ionization model called BBNBI. It takes into account the fine structure of the injector, follows the injected neutrals until ionization, and generates a source ensemble of ionized NBI test particles for slowing down calculations. BBNBI can be used as a stand-alone model but together with the particle following code ASCOT it forms a complete and sophisticated tool for simulating neutral beam injection. The test particle ensembles from BBNBI are found to agree well with those produced by PENCIL for JET, and those produced by NUBEAM both for JET and ASDEX Upgrade plasmas. The first comprehensive comparisons of beam slowing down profiles of interest from BBNBI + ASCOT with results from PENCIL and NUBEAM/TRANSP, for both JET and AUG, are presented. It is shown that, for an axisymmetric plasma, BBNBI + ASCOT and NUBEAM agree remarkably well. Together with earlier 3D studies, these results further validate using BBNBI + ASCOT also for studying phenomena that require particle following in a truly three-dimensional geometry.

  20. Inference of Gene Regulatory Network Based on Local Bayesian Networks

    PubMed Central

    Liu, Fei; Zhang, Shao-Wu; Guo, Wei-Feng; Chen, Luonan

    2016-01-01

    The inference of gene regulatory networks (GRNs) from expression data can mine the direct regulations among genes and gain deep insights into biological processes at a network level. During past decades, numerous computational approaches have been introduced for inferring the GRNs. However, many of them still suffer from various problems, e.g., Bayesian network (BN) methods cannot handle large-scale networks due to their high computational complexity, while information theory-based methods cannot identify the directions of regulatory interactions and also suffer from false positive/negative problems. To overcome the limitations, in this work we present a novel algorithm, namely local Bayesian network (LBN), to infer GRNs from gene expression data by using the network decomposition strategy and false-positive edge elimination scheme. Specifically, LBN algorithm first uses conditional mutual information (CMI) to construct an initial network or GRN, which is decomposed into a number of local networks or GRNs. Then, BN method is employed to generate a series of local BNs by selecting the k-nearest neighbors of each gene as its candidate regulatory genes, which significantly reduces the exponential search space from all possible GRN structures. Integrating these local BNs forms a tentative network or GRN by performing CMI, which reduces redundant regulations in the GRN and thus alleviates the false positive problem. The final network or GRN can be obtained by iteratively performing CMI and local BN on the tentative network. In the iterative process, the false or redundant regulations are gradually removed. When tested on the benchmark GRN datasets from DREAM challenge as well as the SOS DNA repair network in E.coli, our results suggest that LBN outperforms other state-of-the-art methods (ARACNE, GENIE3 and NARROMI) significantly, with more accurate and robust performance. In particular, the decomposition strategy with local Bayesian networks not only effectively reduce

  1. Inference of Gene Regulatory Network Based on Local Bayesian Networks.

    PubMed

    Liu, Fei; Zhang, Shao-Wu; Guo, Wei-Feng; Wei, Ze-Gang; Chen, Luonan

    2016-08-01

    The inference of gene regulatory networks (GRNs) from expression data can mine the direct regulations among genes and gain deep insights into biological processes at a network level. During past decades, numerous computational approaches have been introduced for inferring the GRNs. However, many of them still suffer from various problems, e.g., Bayesian network (BN) methods cannot handle large-scale networks due to their high computational complexity, while information theory-based methods cannot identify the directions of regulatory interactions and also suffer from false positive/negative problems. To overcome the limitations, in this work we present a novel algorithm, namely local Bayesian network (LBN), to infer GRNs from gene expression data by using the network decomposition strategy and false-positive edge elimination scheme. Specifically, LBN algorithm first uses conditional mutual information (CMI) to construct an initial network or GRN, which is decomposed into a number of local networks or GRNs. Then, BN method is employed to generate a series of local BNs by selecting the k-nearest neighbors of each gene as its candidate regulatory genes, which significantly reduces the exponential search space from all possible GRN structures. Integrating these local BNs forms a tentative network or GRN by performing CMI, which reduces redundant regulations in the GRN and thus alleviates the false positive problem. The final network or GRN can be obtained by iteratively performing CMI and local BN on the tentative network. In the iterative process, the false or redundant regulations are gradually removed. When tested on the benchmark GRN datasets from DREAM challenge as well as the SOS DNA repair network in E.coli, our results suggest that LBN outperforms other state-of-the-art methods (ARACNE, GENIE3 and NARROMI) significantly, with more accurate and robust performance. In particular, the decomposition strategy with local Bayesian networks not only effectively reduce

  2. [Ecological toxicity of aluminum-based coagulant on representative corps in neutral environment].

    PubMed

    Zhang, Kaisong; Zhou, Qixing

    2005-11-01

    By the terrestrial ecotoxicological methods of seed germination and root elongation, and with aluminum-based coagulant AlCl3 which was widely used in wastewater- and water treatment as an example, this work studied the toxicological effects of aluminum-based coagulants on representative crops, including radish Raphanus sativus, cabbage Brassica chinensis and wheat Triticum aestivum, over a range of exposure concentrations under the neutral condition (pH= 7.0), with contrast to an acid condition (pH= 4.00). The results indicated that there was a significantly positive correlation between the concentration of AlCl3 and the inhibitory rate of root elongation and seed germination either under pH 7.0 or 4.0 (P < 0.01). Cabbage and wheat was more susceptive to AlCl3 toxicity under acid than under neutral condition, while radish was in adverse. The minimum inhibitory concentration of AlCl3 (< 2.0 mg x L(-1)) was lower under neutral than under acid condition. PMID:16471362

  3. Highly active cobalt phosphate and borate based oxygen evolving catalysts operating in neutral and natural waters

    SciTech Connect

    Esswein, AJ; Surendranath, Y; Reece, SY; Nocera, DG

    2011-02-01

    A high surface area electrode is functionalized with cobalt-based oxygen evolving catalysts (Co-OEC = electrodeposited from pH 7 phosphate, Pi, pH 8.5 methylphosphonate, MePi, and pH 9.2 borate electrolyte, Bi). Co-OEC prepared from MePi and operated in Pi and Bi achieves a current density of 100 mA cm(-2) for water oxidation at 442 and 363 mV overpotential, respectively. The catalyst retains activity in near-neutral pH buffered electrolyte in natural waters such as those from the Charles River (Cambridge, MA) and seawater (Woods Hole, MA). The efficacy and ease of operation of anodes functionalized with Co-OEC at appreciable current density together with its ability to operate in near neutral pH buffered natural water sources bodes well for the translation of this catalyst to a viable renewable energy storage technology.

  4. Overview of the negative ion based neutral beam injectors for ITER

    NASA Astrophysics Data System (ADS)

    Schunke, B.; Boilson, D.; Chareyre, J.; Choi, C.-H.; Decamps, H.; El-Ouazzani, A.; Geli, F.; Graceffa, J.; Hemsworth, R.; Kushwah, M.; Roux, K.; Shah, D.; Singh, M.; Svensson, L.; Urbani, M.

    2016-02-01

    The ITER baseline foresees 2 Heating Neutral Beams (HNB's) based on 1 MeV 40 A D- negative ion accelerators, each capable of delivering 16.7 MW of deuterium atoms to the DT plasma, with an optional 3rd HNB injector foreseen as a possible upgrade. In addition, a dedicated diagnostic neutral beam will be injecting ≈22 A of H0 at 100 keV as the probe beam for charge exchange recombination spectroscopy. The integration of the injectors into the ITER plant is nearly finished necessitating only refinements. A large number of components have passed the final design stage, manufacturing has started, and the essential test beds—for the prototype route chosen—will soon be ready to start.

  5. Overview of the negative ion based neutral beam injectors for ITER.

    PubMed

    Schunke, B; Boilson, D; Chareyre, J; Choi, C-H; Decamps, H; El-Ouazzani, A; Geli, F; Graceffa, J; Hemsworth, R; Kushwah, M; Roux, K; Shah, D; Singh, M; Svensson, L; Urbani, M

    2016-02-01

    The ITER baseline foresees 2 Heating Neutral Beams (HNB's) based on 1 MeV 40 A D(-) negative ion accelerators, each capable of delivering 16.7 MW of deuterium atoms to the DT plasma, with an optional 3rd HNB injector foreseen as a possible upgrade. In addition, a dedicated diagnostic neutral beam will be injecting ≈22 A of H(0) at 100 keV as the probe beam for charge exchange recombination spectroscopy. The integration of the injectors into the ITER plant is nearly finished necessitating only refinements. A large number of components have passed the final design stage, manufacturing has started, and the essential test beds-for the prototype route chosen-will soon be ready to start. PMID:26932111

  6. Neural network based architectures for aerospace applications

    NASA Technical Reports Server (NTRS)

    Ricart, Richard

    1987-01-01

    A brief history of the field of neural networks research is given and some simple concepts are described. In addition, some neural network based avionics research and development programs are reviewed. The need for the United States Air Force and NASA to assume a leadership role in supporting this technology is stressed.

  7. Network-Based Classrooms: Promises and Realities.

    ERIC Educational Resources Information Center

    Bruce, Bertram C., Ed.; And Others

    Exploring how new technologies and new pedagogies transform and are transformed by existing institutions, this book presents 14 essays that discuss network-based classrooms in which students use communications software on computer networks to converse in writing. The first part of the book discusses general themes and issues of the ENFI…

  8. Network-Based Electronic Serials.

    ERIC Educational Resources Information Center

    Bailey, Charles W., Jr.

    1992-01-01

    Discusses electronic serials that are available on noncommercial international computer networks such as BITNET and Internet. Issues affecting libraries are discussed, including access and ownership; computer conferences are considered; examples of electronic newsletters and electronic journals are described; and the possible future of electronic…

  9. Searching the Damaged Outgoing Feeder in Networks with Insulated Neutral by Phase-to-ground Fault

    NASA Astrophysics Data System (ADS)

    Sivokobylenko, Vitaliy; Kuzmenko, Dmitriy

    2010-01-01

    The method of searching the damaged feeder was improved by alternate disconnecting of feeder circuit-breakers, which allow to enlarge reliability of the systems of power supply by diminishing the number of multiple earth fault in electric network. Diminishing the number of multiple earth faults is attained by exception of switching overvoltage, because commutations of feeder circuit-breakers are carrying out when shunting circuit breaker is closed. The detection of damage in the feeder, when this method is used, is produced on the change of phase of current in the circuit of shunting circuit breaker after disconnecting of circuit-breaker of this feeder.

  10. Dynamics-based centrality for directed networks

    NASA Astrophysics Data System (ADS)

    Masuda, Naoki; Kori, Hiroshi

    2010-11-01

    Determining the relative importance of nodes in directed networks is important in, for example, ranking websites, publications, and sports teams, and for understanding signal flows in systems biology. A prevailing centrality measure in this respect is the PageRank. In this work, we focus on another class of centrality derived from the Laplacian of the network. We extend the Laplacian-based centrality, which has mainly been applied to strongly connected networks, to the case of general directed networks such that we can quantitatively compare arbitrary nodes. Toward this end, we adopt the idea used in the PageRank to introduce global connectivity between all the pairs of nodes with a certain strength. Numerical simulations are carried out on some networks. We also offer interpretations of the Laplacian-based centrality for general directed networks in terms of various dynamical and structural properties of networks. Importantly, the Laplacian-based centrality defined as the stationary density of the continuous-time random walk with random jumps is shown to be equivalent to the absorption probability of the random walk with sinks at each node but without random jumps. Similarly, the proposed centrality represents the importance of nodes in dynamics on the original network supplied with sinks but not with random jumps.

  11. Synthesis, molecular structure, and properties of a neutral Schiff base phenolic complex of magnesium

    SciTech Connect

    Polyakov, V.R.; Sharma, V.; Crankshaw, C.L.; Piwnica-Worms, D.

    1998-09-07

    Multidrug resistance (MDR) in cancer mediated by the MDR1 P-glycoprotein (Pgp), a 140--180 kDa plasma membrane protein, renders chemotherapeutic treatment ineffective by pumping a variety of natural product cytotoxic agents and xenobiotic compounds out of cancer cells. Pgp has been a major target for synthesis and development of both therapeutic antagonists that block its transport function and diagnostic radiopharmaceuticals that are transported by the protein for use in functional imaging of Pgp transport activity in tumors in vivo. Most, but not all, compounds that interact with Pgp are hydrophobic and cationic at physiological pH. To further understand the Pgp targeting properties, the authors sought to directly evaluate the effect of charge of the complex on Pgp interactions. This could be done by comparing the cytotoxicity profile of a neutral complex to that of an identical, but positively charged, complex in both drug-sensitive and multidrug-resistant cancer cells. Thus, a neutral analogue of the Ga(III) and Fe(III) complexes was desired. Herein the authors describe the synthesis and structure of a novel neutral Schiff base Mg complex and evaluate its cytotoxic potency in human drug-sensitive KB-3-1 and multi-drug-resistant KB-8-5 tumor cells.

  12. Simultaneous determination of neutral and uronic sugars based on UV-vis spectrometry combined with PLS.

    PubMed

    Zhang, Ci-Hai; Yun, Yong-Huan; Zhang, Zhi-Min; Liang, Yi-Zeng

    2016-06-01

    A method using partial least squares (PLS) for simultaneous determination of neutral and uronic sugars was developed in this paper. This method is based on the development of the reaction between the analytes and anthrone. The calibration set was built with 25 binary solutions at the concentrations ranging from 20 to 100μg/mL for glucose and from 10 to 50μg/mL for glucuronic acid. An independent prediction set was utilized to check the robustness of the PLS calibration model. The root-mean-square error of prediction (RMSEP) values for neutral and uronic sugars are 1.2233 and 1.9367, respectively. The correlation coefficient for the prediction set (Rp(2)) values for them are 0.9971 and 0.9767, respectively. Compared with the univariate method, the proposed method improves detection accuracy. In addition, it was also applied to commercial polysaccharides and Glycyrrhiza uralensis polysaccharides (GUPs), and the results indicated that the PLS model was suitable for simultaneous determination of neutral and uronic sugars. PMID:26927937

  13. Embedded GIS based on the convergenced network

    NASA Astrophysics Data System (ADS)

    Chen, Zhaiwei; Qi, Qingwen

    2007-06-01

    With the development of modern information technology, Telecommunication network, Computer network and TVBroadcast network are converging rapidly. And the three networks form the base of the modern information industry. Although this convergence is considered a support of all services, their convergence doesn't indicate that physical networks will integrate completely. No one of these networks can take the place of others. In fact, this concept inclines to the convergence of services and the infiltration of function among these three networks. This paper give a deep analysis about the characteristic of GIS in this convergenced environment, and discuss the difference compared with traditional WebGIS. Suppose iTV is the terminal service platform of the three networks' fusion, this paper make a discussion about frame and modules of this kind of GIS. The key techology about iTV-GIS includes embedded operation system, middleware and so on. Set-top box as the most important device to run iTV-GIS program has its particularity. A development phase in virtual mechine before hardware importing is necessary. Then a antetype design of iTV-GIS is given as an example at the end of this paper. This research is just a beginning for developmeing GIS on the platform of the three networks' convergence. The subjects mentoined in this paper is just one implement on iTV virual platform, but wish such attempt will bring GIS to a new circumstance, and supply some material for the research later.

  14. High-Frequency Alternating-Crossed-Field Gel Electrophoresis WithNeutral or Slightly Charged Interpenetrating Networks to Improve DNASeparation

    SciTech Connect

    Boyd, B.; Prausnitz, J.; Blanch, H.

    1998-07-01

    Toward improving DNA separations, this work reports theeffects of high-frequency square-wave AC fields superimposedperpendicular to the direct current (DC) separation field on DNAmigration in both polyacrylamide-based interpenetrating networks (IPNs)and in agarose networks. Compared to standard polyacrylamide gels, IPNsallow the separation of larger DNA (9000 bp vs. 5000 bp at 5 V/cm). Innovel polyacrylamide-based IPNs, an alternating current (AC) field of 5Hz increased the maximum DNA size separable. This effect was extended tolarger DNA sizes with increasing electric-field strength up to andapparently beyond the power supply-limited maximum electric-fieldstrength of 48 V/cm. The orthogonal AC field also increased mobility.These two results combine to yield a reduction in separation time of upto a factor of 20 in novel polyacrylamide-based IPNs. When negativelycharged acrylic-acid groups were incorporated into the IPNs, the use ofthe AC field changed the DNA-network interaction, which altered the sizedependence of DNA mobility. In agarose gels, an AC field of 50 Hzincreased the size range separable; however, there was no increase in DNAmobility. There was no change in size dependence of mobility in an ACfield when the number of charged groups in the agarose network wasincreased. Based on results in the literature, possible mechanisms wereexamined for the effects of the AC field on DNA separation.

  15. NASDA knowledge-based network planning system

    NASA Technical Reports Server (NTRS)

    Yamaya, K.; Fujiwara, M.; Kosugi, S.; Yambe, M.; Ohmori, M.

    1993-01-01

    One of the SODS (space operation and data system) sub-systems, NP (network planning) was the first expert system used by NASDA (national space development agency of Japan) for tracking and control of satellite. The major responsibilities of the NP system are: first, the allocation of network and satellite control resources and, second, the generation of the network operation plan data (NOP) used in automated control of the stations and control center facilities. Up to now, the first task of network resource scheduling was done by network operators. NP system automatically generates schedules using its knowledge base, which contains information on satellite orbits, station availability, which computer is dedicated to which satellite, and how many stations must be available for a particular satellite pass or a certain time period. The NP system is introduced.

  16. Network based sky Brightness Monitor

    NASA Astrophysics Data System (ADS)

    McKenna, Dan; Pulvermacher, R.; Davis, D. R.

    2009-01-01

    We have developed and are currently testing an autonomous 2 channel photometer designed to measure the night sky brightness in the visual wavelengths over a multi-year campaign. The photometer uses a robust silicon sensor filtered with Hoya CM500 glass. The Sky brightness is measured every minute at two elevation angles typically zenith and 20 degrees to monitor brightness and transparency. The Sky Brightness monitor consists of two units, the remote photometer and a network interface. Currently these devices use 2.4 Ghz transceivers with a free space range of 100 meters. The remote unit is battery powered with day time recharging using a solar panel. Data received by the network interface transmits data via standard POP Email protocol. A second version is under development for radio sensitive areas using an optical fiber for data transmission. We will present the current comparison with the National Park Service sky monitoring camera. We will also discuss the calibration methods used for standardization and temperature compensation. This system is expected to be deployed in the next year and be operated by the International Dark Sky Association SKYMONITOR project.

  17. An Iron-based Film for Highly Efficient Electrocatalytic Oxygen Evolution from Neutral Aqueous Solution.

    PubMed

    Chen, Mingxing; Wu, Yizhen; Han, Yongzhen; Lin, Xiaohuan; Sun, Junliang; Zhang, Wei; Cao, Rui

    2015-10-01

    An ultrathin Fe-based film was prepared by electrodeposition from an Fe(II) solution through a fast and simple cyclic voltammetry method. The extremely low Fe loading of 12.3 nmol cm(-2) on indium tin oxide electrodes is crucial for high atom efficiency and transparence of the resulted film. This Fe-based film was shown to be a very efficient electrocatalyst for oxygen evolution from neutral aqueous solution with remarkable activity and stability. In a 34 h controlled potential electrolysis at 1.45 V (vs NHE) and pH 7.0, impressive turnover number of 5.2 × 10(4) and turnover frequency of 1528 h(-1) were obtained. To the best of our knowledge, these values represent one of the highest among electrodeposited catalyst films for water oxidation under comparable conditions. The morphology and the composition of the catalyst film was determined by scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray, and X-ray photoelectron spectroscopy, which all confirmed the deposition of Fe-based materials with Fe(III) oxidation state on the electrode. This study is significant because of the use of iron, the fast and simple cyclic voltammetry electrodeposition, the extremely low catalyst loading and thus the transparency of the catalyst film, the remarkable activity and stability, and the oxygen evolution in neutral aqueous media. PMID:26368828

  18. Identifying Network Public Opinion Leaders Based on Markov Logic Networks

    PubMed Central

    Zhang, Weizhe; Li, Xiaoqiang; He, Hui; Wang, Xing

    2014-01-01

    Public opinion emergencies have important effect on social activities. Recognition of special communities like opinion leaders can contribute to a comprehensive understanding of the development trend of public opinion. In this paper, a network opinion leader recognition method based on relational data was put forward, and an opinion leader recognition system integrating public opinion data acquisition module, data characteristic selection, and fusion module as well as opinion leader discovery module based on Markov Logic Networks was designed. The designed opinion leader recognition system not only can overcome the incomplete data acquisition and isolated task of traditional methods, but also can recognize opinion leaders comprehensively with considerations to multiple problems by using the relational model. Experimental results demonstrated that, compared with the traditional methods, the proposed method can provide a more accurate opinion leader recognition and has good noise immunity. PMID:24977188

  19. Web100-based Network Diagnostic Tool

    Energy Science and Technology Software Center (ESTSC)

    2003-03-20

    NDT is a client/server based network diagnostic tool developed to aid in finding network performance and configuration problems. The tool measures data transfer rates between two internet hosts (client and server). It also gathers detailed TCP statistical variable counters supplied by the Web100 modified server and uses these TCP variables to compute the theoretical performance rate between the two internet hosts. It then compares these analytical results with the measured results to determine if performancemore » or configuration problems exist and translates these results into plain text messages to aid users and network operators in resolving reported problems.« less

  20. A neural network-based power system stabilizer using power flow characteristics

    SciTech Connect

    Park, Y.M.; Choi, M.S.; Lee, K.Y.

    1996-06-01

    A neural network-based Power System Stabilizer (Neuro-PSS) is designed for a generator connected to a multi-machine power system utilizing the nonlinear power flow dynamics. The uses of power flow dynamics provide a PSS for a wide range operation with reduced size neutral networks. The Neuro-PSS consists of two neutral networks: Neuro-Identifier and Neuro-Controller. The low-frequency oscillation is modeled by the Neuro-Identifier using the power flow dynamics, then a Generalized Backpropagation-Thorough-Time (GBTT) algorithm is developed to train the Neuro-Controller. The simulation results show that the Neuro-PSS designed in this paper performs well with good damping in a wide operation range compared with the conventional PSS.

  1. Leo satellite-based telecommunication network concepts

    NASA Technical Reports Server (NTRS)

    Aiken, John G.; Swan, Peter A.; Leopold, Ray J.

    1991-01-01

    Design considerations are discussed for Low Earth Orbit (LEO) satellite based telecommunications networks. The satellites are assumed to be connected to each other via intersatellite links. They are connected to the end user either directly or through gateways to other networks. Frequency reuse, circuit switching, packet switching, call handoff, and routing for these systems are discussed by analogy with terrestrial cellular (mobile radio) telecommunication systems.

  2. Description-based reappraisal regulate the emotion induced by erotic and neutral images in a Chinese population

    PubMed Central

    Peng, Jiaxin; Qu, Chen; Gu, Ruolei; Luo, Yue-Jia

    2013-01-01

    Previous emotion-regulation research has shown that the late positive potential (LPP) is sensitive to the down-regulation of emotion; however, whether LPP is also sensitive to the up-regulation of emotion remains unclear. The present study examined the description-based reappraisal effects on the up-regulation of positive emotions induced by erotic and neutral images in a Chinese population. Self-reported ratings and event-related potential (ERP) were recorded when subjects viewed pleasant and neutral images, which were shown after either a neutral or positive description. Self-reported results showed that images following positive descriptions were rated as more pleasant compared to images following neutral descriptions. ERP results revealed that the P2, P3, and slow wave (SW) components were larger for erotic pictures than for neutral pictures, while the positive description condition yielded attenuated erotic image-induced P2, P3 and SW and increased SW induced by neutral images. The results demonstrated that description-based reappraisal, as a method of reappraisal, significantly modulates the emotional experience and ERP responses to erotic and neutral images. PMID:23335894

  3. Elements of Network-Based Assessment

    ERIC Educational Resources Information Center

    Gibson, David

    2007-01-01

    Elements of network-based assessment systems are envisioned based on recent advances in knowledge and practice in learning theory, assessment design and delivery, and semantic web interoperability. The architecture takes advantage of the meditating role of technology as well as recent models of assessment systems. This overview of the elements…

  4. Synthesis and characterization of higher amino acid Schiff bases, as monosodium salts and neutral forms. Investigation of the intramolecular hydrogen bonding in all Schiff bases, antibacterial and antifungal activities of neutral forms

    NASA Astrophysics Data System (ADS)

    Güngör, Özlem; Gürkan, Perihan

    2014-09-01

    Schiff bases derived from 5-nitro-salicylaldehyde and 4-aminobutyric acid, 5-aminopentanoic acid and 6-aminohexanoic acid were synthesized both as monosodium salts (1a-3a) and neutral forms (1b-3b). The monosodium-Schiff bases were characterized by elemental analysis, 1H/13C NMR, IR, powder XRD, UV-vis spectra and conductivity measurements. The neutral-Schiff bases were characterized by elemental analysis, 1H/13C NMR, 2D NMR (HMQC), mass, IR, powder XRD, UV-vis spectra and conductivity measurements. The intramolecular hydrogen bonding and related tautomeric equilibria in all the Schiff bases were studied by UV-vis and 1H NMR spectra in solution. Additionally, the neutral-Schiff bases were screened against Staphylococcus aureus-EB18, S. aureus-ATCC 25923, Escherichia coli-ATCC 11230, Candida albicans-M3 and C. albicans-ATCC 16231.

  5. Comparative study of performance of neutral axis tracking based damage detection

    NASA Astrophysics Data System (ADS)

    Soman, R.; Malinowski, P.; Ostachowicz, W.

    2015-07-01

    This paper presents a comparative study of a novel SHM technique for damage isolation. The performance of the Neutral Axis (NA) tracking based damage detection strategy is compared to other popularly used vibration based damage detection methods viz. ECOMAC, Mode Shape Curvature Method and Strain Flexibility Index Method. The sensitivity of the novel method is compared under changing ambient temperature conditions and in the presence of measurement noise. Finite Element Analysis (FEA) of the DTU 10 MW Wind Turbine was conducted to compare the local damage identification capability of each method and the results are presented. Under the conditions examined, the proposed method was found to be robust to ambient condition changes and measurement noise. The damage identification in some is either at par with the methods mentioned in the literature or better under the investigated damage scenarios.

  6. Performance of positive ion based high power ion source of EAST neutral beam injector.

    PubMed

    Hu, Chundong; Xie, Yahong; Xie, Yuanlai; Liu, Sheng; Xu, Yongjian; Liang, Lizhen; Jiang, Caichao; Li, Jun; Liu, Zhimin

    2016-02-01

    The positive ion based source with a hot cathode based arc chamber and a tetrode accelerator was employed for a neutral beam injector on the experimental advanced superconducting tokamak (EAST). Four ion sources were developed and each ion source has produced 4 MW @ 80 keV hydrogen beam on the test bed. 100 s long pulse operation with modulated beam has also been tested on the test bed. The accelerator was upgraded from circular shaped to diamond shaped in the latest two ion sources. In the latest campaign of EAST experiment, four ion sources injected more than 4 MW deuterium beam with beam energy of 60 keV into EAST. PMID:26932029

  7. Neutral cluster debris dynamics in droplet-based laser-produced plasma sources

    NASA Astrophysics Data System (ADS)

    Hudgins, Duane; Gambino, Nadia; Rollinger, Bob; Abhari, Reza

    2016-05-01

    The neutral cluster debris dynamics of a droplet-based laser-produced plasma is studied experimentally and analytically. Experiments were done imaging the debris with a high-speed shadowgraph system and using image processing to determine the droplet debris mean radial velocity \\overline{V} dependence on laser pulse irradiance E e. The data shows a power law dependence between the mean radial debris velocity and the incident irradiance giving \\overline{V}\\propto E\\text{e}n with n≈ 0.65 . A scaled analytical model was derived modeling the plasma ablation pressure on the droplet surface as the primary momentum exchange mechanism between the unablated droplet material and the laser pulse. The relationship between droplet debris trajectory and the droplet alignment with the laser was quantified analytically. The derived analytical model determines that the neutral cluster debris trajectory for an ablated droplet is a function of the laser profile f L, the droplet diameter D and the axial misalignment h between the laser axis and the droplet center. The analytical calculations from these models were found to be in good agreement with the measurements. This analysis has practical significance for understanding ablated droplet debris, droplet deformation by laser pulsing, and droplet breakup from very short timescale shocks.

  8. Autonomous robot behavior based on neural networks

    NASA Astrophysics Data System (ADS)

    Grolinger, Katarina; Jerbic, Bojan; Vranjes, Bozo

    1997-04-01

    The purpose of autonomous robot is to solve various tasks while adapting its behavior to the variable environment, expecting it is able to navigate much like a human would, including handling uncertain and unexpected obstacles. To achieve this the robot has to be able to find solution to unknown situations, to learn experienced knowledge, that means action procedure together with corresponding knowledge on the work space structure, and to recognize working environment. The planning of the intelligent robot behavior presented in this paper implements the reinforcement learning based on strategic and random attempts for finding solution and neural network approach for memorizing and recognizing work space structure (structural assignment problem). Some of the well known neural networks based on unsupervised learning are considered with regard to the structural assignment problem. The adaptive fuzzy shadowed neural network is developed. It has the additional shadowed hidden layer, specific learning rule and initialization phase. The developed neural network combines advantages of networks based on the Adaptive Resonance Theory and using shadowed hidden layer provides ability to recognize lightly translated or rotated obstacles in any direction.

  9. Analysis of Cross-Reactive Neutralizing Antibodies in Human HFMD Serum with an EV71 Pseudovirus-Based Assay

    PubMed Central

    Jin, Jun; Xu, Lin; Sun, Shiyang; Jiang, Liping; Li, Xiaojun; Shao, Jie; Ma, Hongxia; Huang, Xueyong; Guo, Shijie; Chen, Haiying; Cheng, Tong; Yang, Lisheng; Su, Weiheng; Kong, Wei; Liang, Zhenglun; Jiang, Chunlai

    2014-01-01

    Hand, foot and mouth disease, associated with enterovirus 71 (EV71) infections, has recently become an important public health issue throughout the world. Serum neutralizing antibodies are major indicators of EV71 infection and protective immunity. However, the potential for cross-reactivity of neutralizing antibodies for different EV71 genotypes and subgenotypes is unclear. Here we measured the cross-reactive neutralizing antibody titers against EV71 of different genotypes or subgenotypes in sera collected from EV71-infected children and vaccine-inoculated children in a phase III clinical trial (ClinicalTrials.gov Identifier: NCT01636245) using a new pseudovirus-based neutralization assay. Antibodies induced by EV71-C4a were cross-reactive for different EV71 genotypes, demonstrating that C4a is a good candidate strain for an EV71 vaccine. Our study also demonstrated that this new assay is practical for analyses of clinical samples from epidemiological and vaccine studies. PMID:24964084

  10. Separation of a single photon and products of the pi0,eta and K0s meson neutral decay channels using neural network

    NASA Astrophysics Data System (ADS)

    Bandurin, Dmitry V.; Skachkov, Nikolaj B.

    2004-04-01

    The artificial neural network approach is used for separation of signals from a single photon gamma and products of the pi0,eta and K0s meson neutral decay channels on the basis of the data from the CMS electromagnetic calorimeter alone. Rejection values for the three types of mesons as a function of single photon selection efficiencies are obtained for two pseudorapidity regions and initial Et of 20, 40, 60 and 100 GeV.

  11. Overlapping Community Detection based on Network Decomposition

    NASA Astrophysics Data System (ADS)

    Ding, Zhuanlian; Zhang, Xingyi; Sun, Dengdi; Luo, Bin

    2016-04-01

    Community detection in complex network has become a vital step to understand the structure and dynamics of networks in various fields. However, traditional node clustering and relatively new proposed link clustering methods have inherent drawbacks to discover overlapping communities. Node clustering is inadequate to capture the pervasive overlaps, while link clustering is often criticized due to the high computational cost and ambiguous definition of communities. So, overlapping community detection is still a formidable challenge. In this work, we propose a new overlapping community detection algorithm based on network decomposition, called NDOCD. Specifically, NDOCD iteratively splits the network by removing all links in derived link communities, which are identified by utilizing node clustering technique. The network decomposition contributes to reducing the computation time and noise link elimination conduces to improving the quality of obtained communities. Besides, we employ node clustering technique rather than link similarity measure to discover link communities, thus NDOCD avoids an ambiguous definition of community and becomes less time-consuming. We test our approach on both synthetic and real-world networks. Results demonstrate the superior performance of our approach both in computation time and accuracy compared to state-of-the-art algorithms.

  12. Overlapping Community Detection based on Network Decomposition

    PubMed Central

    Ding, Zhuanlian; Zhang, Xingyi; Sun, Dengdi; Luo, Bin

    2016-01-01

    Community detection in complex network has become a vital step to understand the structure and dynamics of networks in various fields. However, traditional node clustering and relatively new proposed link clustering methods have inherent drawbacks to discover overlapping communities. Node clustering is inadequate to capture the pervasive overlaps, while link clustering is often criticized due to the high computational cost and ambiguous definition of communities. So, overlapping community detection is still a formidable challenge. In this work, we propose a new overlapping community detection algorithm based on network decomposition, called NDOCD. Specifically, NDOCD iteratively splits the network by removing all links in derived link communities, which are identified by utilizing node clustering technique. The network decomposition contributes to reducing the computation time and noise link elimination conduces to improving the quality of obtained communities. Besides, we employ node clustering technique rather than link similarity measure to discover link communities, thus NDOCD avoids an ambiguous definition of community and becomes less time-consuming. We test our approach on both synthetic and real-world networks. Results demonstrate the superior performance of our approach both in computation time and accuracy compared to state-of-the-art algorithms. PMID:27066904

  13. Overlapping Community Detection based on Network Decomposition.

    PubMed

    Ding, Zhuanlian; Zhang, Xingyi; Sun, Dengdi; Luo, Bin

    2016-01-01

    Community detection in complex network has become a vital step to understand the structure and dynamics of networks in various fields. However, traditional node clustering and relatively new proposed link clustering methods have inherent drawbacks to discover overlapping communities. Node clustering is inadequate to capture the pervasive overlaps, while link clustering is often criticized due to the high computational cost and ambiguous definition of communities. So, overlapping community detection is still a formidable challenge. In this work, we propose a new overlapping community detection algorithm based on network decomposition, called NDOCD. Specifically, NDOCD iteratively splits the network by removing all links in derived link communities, which are identified by utilizing node clustering technique. The network decomposition contributes to reducing the computation time and noise link elimination conduces to improving the quality of obtained communities. Besides, we employ node clustering technique rather than link similarity measure to discover link communities, thus NDOCD avoids an ambiguous definition of community and becomes less time-consuming. We test our approach on both synthetic and real-world networks. Results demonstrate the superior performance of our approach both in computation time and accuracy compared to state-of-the-art algorithms. PMID:27066904

  14. Motion detection based on recurrent network dynamics

    PubMed Central

    Joukes, Jeroen; Hartmann, Till S.; Krekelberg, Bart

    2014-01-01

    The detection of visual motion requires temporal delays to compare current with earlier visual input. Models of motion detection assume that these delays reside in separate classes of slow and fast thalamic cells, or slow and fast synaptic transmission. We used a data-driven modeling approach to generate a model that instead uses recurrent network dynamics with a single, fixed temporal integration window to implement the velocity computation. This model successfully reproduced the temporal response dynamics of a population of motion sensitive neurons in macaque middle temporal area (MT) and its constituent parts matched many of the properties found in the motion processing pathway (e.g., Gabor-like receptive fields (RFs), simple and complex cells, spatially asymmetric excitation and inhibition). Reverse correlation analysis revealed that a simplified network based on first and second order space-time correlations of the recurrent model behaved much like a feedforward motion energy (ME) model. The feedforward model, however, failed to capture the full speed tuning and direction selectivity properties based on higher than second order space-time correlations typically found in MT. These findings support the idea that recurrent network connectivity can create temporal delays to compute velocity. Moreover, the model explains why the motion detection system often behaves like a feedforward ME network, even though the anatomical evidence strongly suggests that this network should be dominated by recurrent feedback. PMID:25565992

  15. Molecular tectonics: heterometallic coordination networks based on a Pt(II) organometallic metallatecton.

    PubMed

    Zigon, Nicolas; Kyritsakas, Nathalie; Hosseini, Mir Wais

    2015-08-28

    Combinations of a neutral organometallic tecton based on a square planar Pt(ii) complex bearing two triphenylphosphine groups and two 4-ethynylpyridyl coordinating moieties in trans positions, with various metal halides (MX2, M = Co(ii), Ni(ii), Cd(ii), X = Cl(-) or Br(-)) lead to the formation of 2D grid type heterobimetallic coordination networks in the crystalline phase. PMID:26204438

  16. Tailored-waveguide based photonic chip for manipulating an array of single neutral atoms.

    PubMed

    Ke, Min; Zhou, Feng; Li, Xiao; Wang, Jin; Zhan, Mingsheng

    2016-05-01

    We propose a tailored-waveguide based photonic chip with the functions of trapping, coherently manipulating, detecting and individually addressing an array of single neutral atoms. Such photonic chip consists of an array of independent functional units spaced by a few micrometers, each of which is comprised of one silica-on-silicon optical waveguide and one phase Fresnel microlens etched in the middle of the output interface of the optical waveguide. We fabricated a number of photonic chips with 7 functional units and measured optical characteristics of these chips. We further propose feasible schemes to realize the functions of such photonic chip. The photonic chip is stable, scalable and can be combined with other integrated devices, such as atom chips, and can be used in the future hybrid quantum system and photonic quantum devices. PMID:27137532

  17. Network based high performance concurrent computing

    SciTech Connect

    Sunderam, V.S.

    1991-01-01

    The overall objectives of this project are to investigate research issues pertaining to programming tools and efficiency issues in network based concurrent computing systems. The basis for these efforts is the PVM project that evolved during my visits to Oak Ridge Laboratories under the DOE Faculty Research Participation program; I continue to collaborate with researchers at Oak Ridge on some portions of the project.

  18. Dissecting a Network-Based Education System

    ERIC Educational Resources Information Center

    Davis, Tiffany; Yoo, Seong-Moo; Pan, Wendi

    2005-01-01

    The Alabama Learning Exchange (ALEX; www.alex.state.al.us) is a network-based education system designed and implemented to help improve education in Alabama. It accomplishes this goal by providing a single location for the state's K-12 educators to find information that will help improve their classroom effectiveness. The ALEX system includes…

  19. The implementation of a standards based heterogeneous network

    SciTech Connect

    Eldridge, J.M.; Tolendino, L.F.

    1991-08-05

    Computer networks, supporting an organization's activities, are prevalent and very important to the organization's mission. Implementing a heterogenous organizational network allows the staff to select the computing environment that best supports their job requirements. This paper outlines the lessons learned implementing a heterogenous computer network based on networking standards such as TCP/IP and Ethernet. Such a network is a viable alternative to a proprietary, vendor supported network and can provide all the functionality customers expect in a computer network. 2 figs.

  20. A Neutralizing Antibody Assay Based on a Reporter of Antibody-Dependent Cell-Mediated Cytotoxicity.

    PubMed

    Wu, Yuling; Li, Jia J; Kim, Hyun Jun; Liu, Xu; Liu, Weiyi; Akhgar, Ahmad; Bowen, Michael A; Spitz, Susan; Jiang, Xu-Rong; Roskos, Lorin K; White, Wendy I

    2015-11-01

    Benralizumab is a humanized anti-IL5 receptor α (IL5Rα) monoclonal antibody (mAb) with enhanced (afucosylation) antibody-dependent cell-mediated cytotoxicity (ADCC) function. An ADCC reporter cell-based neutralizing antibody (NAb) assay was developed and characterized to detect NAb against benralizumab in human serum to support the clinical development of benralizumab. The optimal ratio of target cells to effector cells was 3:1. Neither parental benralizumab (fucosylated) nor benralizumab Fab resulted in ADCC activity, confirming the requirement for ADCC activity in the NAb assay. The serum tolerance of the cells was determined to be 2.5%. The cut point derived from normal and asthma serum samples was comparable. The effective range of benralizumab was determined, and 35 ng/mL [80% maximal effective concentration (EC80)] was chosen as the standard concentration to run in the assessment of NAb. An affinity purified goat anti-benralizumab polyclonal idiotype antibody preparation was shown to have NAb since it inhibited ADCC activity in a dose-dependent fashion. The low endogenous concentrations of IL5 and soluble IL5 receptor (sIL5R) did not demonstrate to interfere with the assay. The estimated assay sensitivities at the cut point were 1.02 and 1.10 μg/mL as determined by the surrogate neutralizing goat polyclonal and mouse monoclonal anti-drug antibody (ADA) controls, respectively. The assay can detect NAb (at 2.5 μg/mL) in the presence of 0.78 μg/mL benralizumab. The assay was not susceptible to non-specific matrix effects. This study provides an approach and feasibility of developing an ADCC cell-based NAb assay to support biopharmaceuticals with an ADCC function. PMID:26205082

  1. Secured network sensor-based defense system

    NASA Astrophysics Data System (ADS)

    Wei, Sixiao; Shen, Dan; Ge, Linqiang; Yu, Wei; Blasch, Erik P.; Pham, Khanh D.; Chen, Genshe

    2015-05-01

    Network sensor-based defense (NSD) systems have been widely used to defend against cyber threats. Nonetheless, if the adversary finds ways to identify the location of monitor sensors, the effectiveness of NSD systems can be reduced. In this paper, we propose both temporal and spatial perturbation based defense mechanisms to secure NSD systems and make the monitor sensor invisible to the adversary. The temporal-perturbation based defense manipulates the timing information of published data so that the probability of successfully recognizing monitor sensors can be reduced. The spatial-perturbation based defense dynamically redeploys monitor sensors in the network so that the adversary cannot obtain the complete information to recognize all of the monitor sensors. We carried out experiments using real-world traffic traces to evaluate the effectiveness of our proposed defense mechanisms. Our data shows that our proposed defense mechanisms can reduce the attack accuracy of recognizing detection sensors.

  2. Human Antibody Titers to Epstein-Barr Virus (EBV) gp350 Correlate with Neutralization of Infectivity Better than Antibody Titers to EBV gp42 Using a Rapid Flow Cytometry-Based EBV Neutralization Assay

    PubMed Central

    Sashihara, Junji; Burbelo, Peter D.; Savoldo, Barbara; Pierson, Theodore C.; Cohen, Jeffrey I.

    2009-01-01

    Measurement of neutralizing antibodies to Epstein-Barr virus (EBV) is important for evaluation of candidate vaccines. The current neutralization assay is based on antibody inhibition of EBV transformation of B cells and requires 6 weeks to perform. We developed a rapid, quantitative flow cytometry assay and show that neutralizing antibody titers measured by the new assay strongly correlate with antibody titers in the standard transformation-based assay. Antibodies to EBV gp350 and gp42 have been shown to block infection of B cells by EBV. Using new assays to quantify antibodies to these glycoproteins, we show for the first time that that human plasma contains high titers of antibody to gp42; these titers correlate with neutralization of EBV infectivity or transformation. Furthermore, we show that antibody titers to EBV gp350 correlate more strongly with neutralization than antibody titers to gp42. These assays should be useful in accessing antibody responses to candidate EBV vaccines. PMID:19584018

  3. Valorization of lubricant-based wastewater for bacterial neutral lipids production: Growth-linked biosynthesis.

    PubMed

    Da Silva, Pedro D M P; Lima, Filipa; Alves, Maria Madalena; Bijmans, Martijn F M; Pereira, Maria Alcina

    2016-09-15

    Lipids produced by microorganisms are currently of great interest as raw material for either biofuels or oleochemicals production. Significant biosynthesis of neutral lipids, such as triacylglycerol (TAG) and wax esters (WE) are thought to be limited to a few strains. Hydrocarbonoclastic bacteria (HCB), key players in bioremediation of hydrocarbon contaminated ecosystems, are among this group of strains. Hydrocarbon rich wastewaters have been overlooked concerning their potential as raw material for microbial lipids production. In this study, lubricant-based wastewater was fed, as sole carbon source, to two HCB representative wild strains: Alcanivorax borkumensis SK2, and Rhodococcus opacus PD630. Neutral lipid production was observed with both strains cultivated under uncontrolled conditions of pH and dissolved oxygen. A. borkumensis SK2 was further investigated in a pH- and OD-controlled fermenter. Different phases were assessed separately in terms of lipids production and alkanes removal. The maximum TAG production rate occurred during stationary phase (4 mg-TAG/L h). The maximum production rate of WE-like compounds was 15 mg/L h, and was observed during exponential growth phase. Hydrocarbons removal was 97% of the gas chromatography (GC) resolved straight-chain alkanes. The maximum removal rate was observed during exponential growth phase (6 mg-alkanes/L h). This investigation proposes a novel approach for the management of lubricant waste oil, aiming at its conversion into valuable lipids. The feasibility of the concept is demonstrated under low salt (0.3%) and saline (3.3%) conditions, and presents clues for its technological development, since growth associated oil production opens the possibility for establishing continuous fermentation processes. PMID:27244293

  4. Significant Performance Enhancement in Asymmetric Supercapacitors based on Metal Oxides, Carbon nanotubes and Neutral Aqueous Electrolyte

    PubMed Central

    Singh, Arvinder; Chandra, Amreesh

    2015-01-01

    Amongst the materials being investigated for supercapacitor electrodes, carbon based materials are most investigated. However, pure carbon materials suffer from inherent physical processes which limit the maximum specific energy and power that can be achieved in an energy storage device. Therefore, use of carbon-based composites with suitable nano-materials is attaining prominence. The synergistic effect between the pseudocapacitive nanomaterials (high specific energy) and carbon (high specific power) is expected to deliver the desired improvements. We report the fabrication of high capacitance asymmetric supercapacitor based on electrodes of composites of SnO2 and V2O5 with multiwall carbon nanotubes and neutral 0.5 M Li2SO4 aqueous electrolyte. The advantages of the fabricated asymmetric supercapacitors are compared with the results published in the literature. The widened operating voltage window is due to the higher over-potential of electrolyte decomposition and a large difference in the work functions of the used metal oxides. The charge balanced device returns the specific capacitance of ~198 F g−1 with corresponding specific energy of ~89 Wh kg−1 at 1 A g−1. The proposed composite systems have shown great potential in fabricating high performance supercapacitors. PMID:26494197

  5. Significant Performance Enhancement in Asymmetric Supercapacitors based on Metal Oxides, Carbon nanotubes and Neutral Aqueous Electrolyte

    NASA Astrophysics Data System (ADS)

    Singh, Arvinder; Chandra, Amreesh

    2015-10-01

    Amongst the materials being investigated for supercapacitor electrodes, carbon based materials are most investigated. However, pure carbon materials suffer from inherent physical processes which limit the maximum specific energy and power that can be achieved in an energy storage device. Therefore, use of carbon-based composites with suitable nano-materials is attaining prominence. The synergistic effect between the pseudocapacitive nanomaterials (high specific energy) and carbon (high specific power) is expected to deliver the desired improvements. We report the fabrication of high capacitance asymmetric supercapacitor based on electrodes of composites of SnO2 and V2O5 with multiwall carbon nanotubes and neutral 0.5 M Li2SO4 aqueous electrolyte. The advantages of the fabricated asymmetric supercapacitors are compared with the results published in the literature. The widened operating voltage window is due to the higher over-potential of electrolyte decomposition and a large difference in the work functions of the used metal oxides. The charge balanced device returns the specific capacitance of ~198 F g-1 with corresponding specific energy of ~89 Wh kg-1 at 1 A g-1. The proposed composite systems have shown great potential in fabricating high performance supercapacitors.

  6. Convolutional Neural Network Based dem Super Resolution

    NASA Astrophysics Data System (ADS)

    Chen, Zixuan; Wang, Xuewen; Xu, Zekai; Hou, Wenguang

    2016-06-01

    DEM super resolution is proposed in our previous publication to improve the resolution for a DEM on basis of some learning examples. Meanwhile, the nonlocal algorithm is introduced to deal with it and lots of experiments show that the strategy is feasible. In our publication, the learning examples are defined as the partial original DEM and their related high measurements due to this way can avoid the incompatibility between the data to be processed and the learning examples. To further extent the applications of this new strategy, the learning examples should be diverse and easy to obtain. Yet, it may cause the problem of incompatibility and unrobustness. To overcome it, we intend to investigate a convolutional neural network based method. The input of the convolutional neural network is a low resolution DEM and the output is expected to be its high resolution one. A three layers model will be adopted. The first layer is used to detect some features from the input, the second integrates the detected features to some compressed ones and the final step transforms the compressed features as a new DEM. According to this designed structure, some learning DEMs will be taken to train it. Specifically, the designed network will be optimized by minimizing the error of the output and its expected high resolution DEM. In practical applications, a testing DEM will be input to the convolutional neural network and a super resolution will be obtained. Many experiments show that the CNN based method can obtain better reconstructions than many classic interpolation methods.

  7. Network-based modular latent structure analysis

    PubMed Central

    2014-01-01

    Background High-throughput expression data, such as gene expression and metabolomics data, exhibit modular structures. Groups of features in each module follow a latent factor model, while between modules, the latent factors are quasi-independent. Recovering the latent factors can shed light on the hidden regulation patterns of the expression. The difficulty in detecting such modules and recovering the latent factors lies in the high dimensionality of the data, and the lack of knowledge in module membership. Methods Here we describe a method based on community detection in the co-expression network. It consists of inference-based network construction, module detection, and interacting latent factor detection from modules. Results In simulations, the method outperformed projection-based modular latent factor discovery when the input signals were not Gaussian. We also demonstrate the method's value in real data analysis. Conclusions The new method nMLSA (network-based modular latent structure analysis) is effective in detecting latent structures, and is easy to extend to non-linear cases. The method is available as R code at http://web1.sph.emory.edu/users/tyu8/nMLSA/. PMID:25435002

  8. Network-based recommendation algorithms: A review

    NASA Astrophysics Data System (ADS)

    Yu, Fei; Zeng, An; Gillard, Sébastien; Medo, Matúš

    2016-06-01

    Recommender systems are a vital tool that helps us to overcome the information overload problem. They are being used by most e-commerce web sites and attract the interest of a broad scientific community. A recommender system uses data on users' past preferences to choose new items that might be appreciated by a given individual user. While many approaches to recommendation exist, the approach based on a network representation of the input data has gained considerable attention in the past. We review here a broad range of network-based recommendation algorithms and for the first time compare their performance on three distinct real datasets. We present recommendation topics that go beyond the mere question of which algorithm to use-such as the possible influence of recommendation on the evolution of systems that use it-and finally discuss open research directions and challenges.

  9. Perspective ground-based method for diagnostics of the lower ionosphere and the neutral atmosphere

    NASA Astrophysics Data System (ADS)

    Bakhmetieva, N. V.; Grigoriev, G. I.; Tolmacheva, A. V.

    We present a new perspective ground-based method for diagnostics of the ionosphere and atmosphere parameters. The method uses one of the numerous physical phenomena observed in the ionosphere illuminated by high-power radio waves. It is a generation of the artificial periodic irregularities (APIs) in the ionospheric plasma. The APIs were found while studying the effects of ionospheric high-power HF modification. It was established that the APIs are formed by a standing wave that occurs due to interference between the upwardly radiated radio wave and its reflection off the ionosphere. The API studies are based upon observation of the Bragg backscatter of the pulsed probe radio wave from the artificial periodic structure. Bragg backscatter occurs if the spatial period of the irregularities is equal to half a wavelength of the probe signal. The API techniques makes it possible to obtain the following information: the profiles of electron density from the lower D-region up to the maximum of the F-layer; the irregular structure of the ionosphere including split of the regular E-layer, the sporadic layers; the vertical velocities in the D- and E-regions of the ionosphere; the turbulent velocities, turbulent diffusion coefficients and the turbopause altitude; the neutral temperatures and densities at the E-region altitudes; the parameters of the internal gravity waves and their spectral characteristics; the relative concentration of negative oxygen ions in the D-region. Some new results obtained by the API technique are discussed .

  10. Network-Based Protein Biomarker Discovery Platforms

    PubMed Central

    Kim, Minhyung

    2016-01-01

    The advances in mass spectrometry-based proteomics technologies have enabled the generation of global proteome data from tissue or body fluid samples collected from a broad spectrum of human diseases. Comparative proteomic analysis of global proteome data identifies and prioritizes the proteins showing altered abundances, called differentially expressed proteins (DEPs), in disease samples, compared to control samples. Protein biomarker candidates that can serve as indicators of disease states are then selected as key molecules among these proteins. Recently, it has been addressed that cellular pathways can provide better indications of disease states than individual molecules and also network analysis of the DEPs enables effective identification of cellular pathways altered in disease conditions and key molecules representing the altered cellular pathways. Accordingly, a number of network-based approaches to identify disease-related pathways and representative molecules of such pathways have been developed. In this review, we summarize analytical platforms for network-based protein biomarker discovery and key components in the platforms. PMID:27103885

  11. Community detection based on network communicability

    NASA Astrophysics Data System (ADS)

    Estrada, Ernesto

    2011-03-01

    We propose a new method for detecting communities based on the concept of communicability between nodes in a complex network. This method, designated as N-ComBa K-means, uses a normalized version of the adjacency matrix to build the communicability matrix and then applies K-means clustering to find the communities in a graph. We analyze how this method performs for some pathological cases found in the analysis of the detection limit of communities and propose some possible solutions on the basis of the analysis of the ratio of local to global densities in graphs. We use four different quality criteria for detecting the best clustering and compare the new approach with the Girvan-Newman algorithm for the analysis of two "classical" networks: karate club and bottlenose dolphins. Finally, we analyze the more challenging case of homogeneous networks with community structure, for which the Girvan-Newman completely fails in detecting any clustering. The N-ComBa K-means approach performs very well in these situations and we applied it to detect the community structure in an international trade network of miscellaneous manufactures of metal having these characteristics. Some final remarks about the general philosophy of community detection are also discussed.

  12. Neutralizer optimization

    NASA Technical Reports Server (NTRS)

    Patterson, Michael J.; Mohajeri, Kayhan

    1991-01-01

    The preliminary results of a test program to optimize a neutralizer design for 30 cm xenon ion thrusters are discussed. The impact of neutralizer geometry, neutralizer axial location, and local magnetic fields on neutralizer performance is discussed. The effect of neutralizer performance on overall thruster performance is quantified, for thruster operation in the 0.5-3.2 kW power range. Additionally, these data are compared to data published for other north-south stationkeeping (NSSK) and primary propulsion xenon ion thruster neutralizers.

  13. Angular-divergence calculation for Experimental Advanced Superconducting Tokamak neutral beam injection ion source based on spectroscopic measurements

    SciTech Connect

    Chi, Yuan; Hu, Chundong; Zhuang, Ge

    2014-02-15

    Calorimetric method has been primarily applied for several experimental campaigns to determine the angular divergence of high-current ion source for the neutral beam injection system on the Experimental Advanced Superconducting Tokamak (EAST). A Doppler shift spectroscopy has been developed to provide the secondary measurement of the angular divergence to improve the divergence measurement accuracy and for real-time and non-perturbing measurement. The modified calculation model based on the W7AS neutral beam injectors is adopted to accommodate the slot-type accelerating grids used in the EAST's ion source. Preliminary spectroscopic experimental results are presented comparable to the calorimetrically determined value of theoretical calculation.

  14. Insight into acid-base nucleation experiments by comparison of the chemical composition of positive, negative, and neutral clusters.

    PubMed

    Bianchi, Federico; Praplan, Arnaud P; Sarnela, Nina; Dommen, Josef; Kürten, Andreas; Ortega, Ismael K; Schobesberger, Siegfried; Junninen, Heikki; Simon, Mario; Tröstl, Jasmin; Jokinen, Tuija; Sipilä, Mikko; Adamov, Alexey; Amorim, Antonio; Almeida, Joao; Breitenlechner, Martin; Duplissy, Jonathan; Ehrhart, Sebastian; Flagan, Richard C; Franchin, Alessandro; Hakala, Jani; Hansel, Armin; Heinritzi, Martin; Kangasluoma, Juha; Keskinen, Helmi; Kim, Jaeseok; Kirkby, Jasper; Laaksonen, Ari; Lawler, Michael J; Lehtipalo, Katrianne; Leiminger, Markus; Makhmutov, Vladimir; Mathot, Serge; Onnela, Antti; Petäjä, Tuukka; Riccobono, Francesco; Rissanen, Matti P; Rondo, Linda; Tomé, António; Virtanen, Annele; Viisanen, Yrjö; Williamson, Christina; Wimmer, Daniela; Winkler, Paul M; Ye, Penglin; Curtius, Joachim; Kulmala, Markku; Worsnop, Douglas R; Donahue, Neil M; Baltensperger, Urs

    2014-12-01

    We investigated the nucleation of sulfuric acid together with two bases (ammonia and dimethylamine), at the CLOUD chamber at CERN. The chemical composition of positive, negative, and neutral clusters was studied using three Atmospheric Pressure interface-Time Of Flight (APi-TOF) mass spectrometers: two were operated in positive and negative mode to detect the chamber ions, while the third was equipped with a nitrate ion chemical ionization source allowing detection of neutral clusters. Taking into account the possible fragmentation that can happen during the charging of the ions or within the first stage of the mass spectrometer, the cluster formation proceeded via essentially one-to-one acid-base addition for all of the clusters, independent of the type of the base. For the positive clusters, the charge is carried by one excess protonated base, while for the negative clusters it is carried by a deprotonated acid; the same is true for the neutral clusters after these have been ionized. During the experiments involving sulfuric acid and dimethylamine, it was possible to study the appearance time for all the clusters (positive, negative, and neutral). It appeared that, after the formation of the clusters containing three molecules of sulfuric acid, the clusters grow at a similar speed, independent of their charge. The growth rate is then probably limited by the arrival rate of sulfuric acid or cluster-cluster collision. PMID:25406110

  15. Neoliberal Common Sense and Race-Neutral Discourses: A Critique of "Evidence-Based" Policy-Making in School Policing

    ERIC Educational Resources Information Center

    Nolan, Kathleen

    2015-01-01

    The author of this paper uses critical discourse analysis and draws on critical social theory and policy studies to analyze the interdiscursivity between neoliberal common sense discourses around crime and safety and race-neutral discourses, "evidence-based" policy, and the research that supports school policing programs. The author…

  16. Analysis of Physical Science Textbooks for Conceptual Frameworks on Acids, Bases and Neutralization: Implications for Students' Conceptual Understanding.

    ERIC Educational Resources Information Center

    Erduran, Sibel

    Eight physical science textbooks were analyzed for coverage on acids, bases, and neutralization. At the level of the text, clarity and coherence of statements were investigated. The conceptual framework for this topic was represented in a concept map which was used as a coding tool for tracing concepts and links present in textbooks. Cognitive…

  17. SIPHORE: Conceptual Study of a High Efficiency Neutral Beam Injector Based on Photo-detachment for Future Fusion Reactors

    SciTech Connect

    Simonin, A.; Christin, L.; Esch, H. de; Garibaldi, P.; Grand, C.; Villecroze, F.; Blondel, C.; Delsart, C.; Drag, C.; Vandevraye, M.; Brillet, A.; Chaibi, W.

    2011-09-26

    An innovative high efficiency neutral beam injector concept for future fusion reactors is under investigation (simulation and R and D) between several laboratories in France, the goal being to perform a feasibility study for the neutralization of intense high energy (1 MeV) negative ion (NI) beams by photo-detachment.The objective of the proposed project is to put together the expertise of three leading groups in negative ion quantum physics, high power stabilized lasers and neutral beam injectors to perform studies of a new injector concept called SIPHORE (SIngle gap PHOto-neutralizer energy REcovery injector), based on the photo-detachment of negative ions and energy recovery of unneutralised ions; the main feature of SIPHORE being the relevance for the future Fusion reactors (DEMO), where high injector efficiency (up to 70-80%), technological simplicity and cost reduction are key issues to be addressed.The paper presents the on-going developments and simulations around this project, such as, a new concept of ion source which would fit with this injector topology and which could solve the remaining uniformity issue of the large size ion source, and, finally, the presentation of the R and D program in the laboratories (LAC, ARTEMIS) around the photo-neutralization for Siphore.

  18. Release time of residual oxygen after dental bleaching with 35% hydrogen peroxide: effect of a catalase-based neutralizing agent.

    PubMed

    Guasso, Bárbara; Salomone, Paloma; Nascimento, Paulo Cícero; Pozzobon, Roselaine Terezinha

    2016-01-01

    This article assessed the effect of a catalase-based agent on residual oxygen (O2) release from teeth exposed to 35% hydrogen peroxide (H2O2). The use of the catalase-based neutralizer agent for 2-3 minutes was able to release residual O2 5 days after exposure to a 35% H2O2-based bleaching gel. PMID:27148658

  19. Improving a Synechocystis-based photoautotrophic chassis through systematic genome mapping and validation of neutral sites

    PubMed Central

    Pinto, Filipe; Pacheco, Catarina C.; Oliveira, Paulo; Montagud, Arnau; Landels, Andrew; Couto, Narciso; Wright, Phillip C.; Urchueguía, Javier F.; Tamagnini, Paula

    2015-01-01

    The use of microorganisms as cell factories frequently requires extensive molecular manipulation. Therefore, the identification of genomic neutral sites for the stable integration of ectopic DNA is required to ensure a successful outcome. Here we describe the genome mapping and validation of five neutral sites in the chromosome of Synechocystis sp. PCC 6803, foreseeing the use of this cyanobacterium as a photoautotrophic chassis. To evaluate the neutrality of these loci, insertion/deletion mutants were produced, and to assess their functionality, a synthetic green fluorescent reporter module was introduced. The constructed integrative vectors include a BioBrick-compatible multiple cloning site insulated by transcription terminators, constituting robust cloning interfaces for synthetic biology approaches. Moreover, Synechocystis mutants (chassis) ready to receive purpose-built synthetic modules/circuits are also available. This work presents a systematic approach to map and validate chromosomal neutral sites in cyanobacteria, and that can be extended to other organisms. PMID:26490728

  20. Improving a Synechocystis-based photoautotrophic chassis through systematic genome mapping and validation of neutral sites.

    PubMed

    Pinto, Filipe; Pacheco, Catarina C; Oliveira, Paulo; Montagud, Arnau; Landels, Andrew; Couto, Narciso; Wright, Phillip C; Urchueguía, Javier F; Tamagnini, Paula

    2015-12-01

    The use of microorganisms as cell factories frequently requires extensive molecular manipulation. Therefore, the identification of genomic neutral sites for the stable integration of ectopic DNA is required to ensure a successful outcome. Here we describe the genome mapping and validation of five neutral sites in the chromosome of Synechocystis sp. PCC 6803, foreseeing the use of this cyanobacterium as a photoautotrophic chassis. To evaluate the neutrality of these loci, insertion/deletion mutants were produced, and to assess their functionality, a synthetic green fluorescent reporter module was introduced. The constructed integrative vectors include a BioBrick-compatible multiple cloning site insulated by transcription terminators, constituting robust cloning interfaces for synthetic biology approaches. Moreover, Synechocystis mutants (chassis) ready to receive purpose-built synthetic modules/circuits are also available. This work presents a systematic approach to map and validate chromosomal neutral sites in cyanobacteria, and that can be extended to other organisms. PMID:26490728

  1. Kalman filter based data fusion for neutral axis tracking in wind turbine towers

    NASA Astrophysics Data System (ADS)

    Soman, Rohan; Malinowski, Pawel; Ostachowicz, Wieslaw; Paulsen, Uwe S.

    2015-03-01

    Wind energy is seen as one of the most promising solutions to man's ever increasing demands of a clean source of energy. In particular to reduce the cost of energy (COE) generated, there are efforts to increase the life-time of the wind turbines, to reduce maintenance costs and to ensure high availability. Maintenance costs may be lowered and the high availability and low repair costs ensured through the use of condition monitoring (CM) and structural health monitoring (SHM). SHM allows early detection of damage and allows maintenance planning. Furthermore, it can allow us to avoid unnecessary downtime, hence increasing the availability of the system. The present work is based on the use of neutral axis (NA) for SHM of the structure. The NA is tracked by data fusion of measured yaw angle and strain through the use of Extended Kalman Filter (EKF). The EKF allows accurate tracking even in the presence of changing ambient conditions. NA is defined as the line or plane in the section of the beam which does not experience any tensile or compressive forces when loaded. The NA is the property of the cross section of the tower and is independent of the applied loads and ambient conditions. Any change in the NA position may be used for detecting and locating the damage. The wind turbine tower has been modelled with FE software ABAQUS and validated on data from load measurements carried out on the 34m high tower of the Nordtank, NTK 500/41 wind turbine.

  2. A facile nanoaggregation strategy for oral delivery of hydrophobic drugs by utilizing acid base neutralization reactions

    NASA Astrophysics Data System (ADS)

    Chen, Huabing; Wan, Jiangling; Wang, Yirui; Mou, Dongsheng; Liu, Hongbin; Xu, Huibi; Yang, Xiangliang

    2008-09-01

    Nanonization strategies have been used to enhance the oral availability of numerous drugs that are poorly soluble in water. Exploring a facile nanonization strategy with highly practical potential is an attractive focus. Here, we report a novel facile nanoaggregation strategy for constructing drug nanoparticles of poorly soluble drugs with pH-dependent solubility by utilizing acid-base neutralization in aqueous solution, thus facilitating the exploration of nanonization in oral delivery for general applicability. We demonstrate that hydrophobic itraconazole dissolved in acid solution formed a growing core and aggregated into nanoparticles in the presence of stabilizers. The nanoparticles, with an average diameter of 279.3 nm and polydispersity index of 0.116, showed a higher dissolution rate when compared with the marketed formulation; the average dissolution was about 91.3%. The in vivo pharmacokinetic studies revealed that the nanoparticles had a rapid absorption and enhanced oral availability. The diet state also showed insignificant impact on the absorption of itraconazole from nanoparticles. This nanoaggregation strategy is a promising nanonization method with a facile process and avoidance of toxic organic solvents for oral delivery of poorly soluble drugs with pH-dependent solubility and reveals a highly practical potential in the pharmaceutical and chemical industries.

  3. Fluorescent reversible regulation based on the interactions of topotecan hydrochloride, neutral red and quantum dots

    NASA Astrophysics Data System (ADS)

    Wang, Linlin; Shen, Yizhong; Liu, Shaopu; Yang, Jidong; Liang, Wanjun; Li, Dan; He, Youqiu

    2015-02-01

    The interactions of topotecan hydrochloride (THC), neutral red (NR) and thioglycolic acid (TGA) capped CdTe/CdS quantum dots (QDs) built a solid base for the controlling of the fluorescent reversible regulation of the system. This study was developed by means of ultraviolet-visible (UV-vis) absorption, fluorescence (FL), resonance Rayleigh scattering (RRS) spectroscopy and transmission electron microscopy (TEM). Corresponding experimental results revealed that the fluorescence of TGA-CdTe/CdS QDs could be effectively quenched by NR, while the RRS of the QDs enhanced gradually with the each increment of NR concentration. After the addition of THC, the strong covalent conjugation between NR and THC which was in carboxylate state enabled NR to be dissociated from the surface of TGA-CdTe/CdS QDs to form more stable complex with THC, thereby enhancing the fluorescence of the TGA-CdTe/CdS QDs-NR system. What is more, through analyzing the optical properties and experimental data of the reaction between TGA-CdTe/CdS QDs and NR, the possible reaction mechanism of the whole system was discussed. This combination of multiple spectroscopic techniques could contribute to the investigation for the fluorescent reversible regulation of QDs and a method could also be established to research the interactions between camptothecin drugs and dyes.

  4. Rheological characterization of cataplasm bases composed of cross-linked partially neutralized polyacrylate hydrogel.

    PubMed

    Wang, Jian; Zhang, Hongqin; An, Dianyun; Yu, Jian; Li, Wei; Shen, Teng; Wang, Jianxin

    2014-10-01

    Viscoelasticity is a useful parameter for characterizing the intrinsic properties of the cross-linked polyacrylate hydrogel used in cataplasm bases. The aim of this study was to investigate the effects of various formulation parameters on the rheological characteristics of polyacrylate hydrogel. The hydrogel layers were formed using a partially neutralized polyacrylate (Viscomate(™)), which contained acrylic acid and sodium acrylate in different copolymerization ratios, as the cross-linked gel framework. Dihydroxyaluminum aminoacetate (DAAA), which produces aluminum ions, was used as the cross-linking agent. Rheological analyses were performed using a "stress amplitude sweep" and a "frequency sweep". The results showed that greater amounts of acrylic acid in the structure of Viscomate as well as higher concentrations of DAAA and Viscomate led to an increase in the elastic modulus (G'). However, greater amounts of acrylic acid in the structure of Viscomate and higher concentrations of DAAA had an opposite on the viscous modulus (G″); this might be owing to higher steric hindrance. The results of this study can serve as guidelines for the optimization of formulations for cataplasms. PMID:24865937

  5. Analysis of the mineral acid-base components of acid-neutralizing capacity in Adirondack Lakes

    NASA Astrophysics Data System (ADS)

    Munson, R. K.; Gherini, S. A.

    1993-04-01

    Mineral acids and bases influence pH largely through their effects on acid-neutralizing capacity (ANC). This influence becomes particularly significant as ANC approaches zero. Analysis of data collected by the Adirondack Lakes Survey Corporation (ALSC) from 1469 lakes throughout the Adirondack region indicates that variations in ANC in these lakes correlate well with base cation concentrations (CB), but not with the sum of mineral acid anion concentrations (CA). This is because (CA) is relatively constant across the Adirondacks, whereas CB varies widely. Processes that supply base cations to solution are ion-specific. Sodium and silica concentrations are well correlated, indicating a common source, mineral weathering. Calcium and magnesium also covary but do not correlate well with silica. This indicates that ion exchange is a significant source of these cations in the absence of carbonate minerals. Iron and manganese concentrations are elevated in the lower waters of some lakes due to reducing conditions. This leads to an ephemeral increase in CB and ANC. When the lakes mix and oxic conditions are restored, these ions largely precipitate from solution. Sulfate is the dominant mineral acid anion in ALSC lakes. Sulfate concentrations are lowest in seepage lakes, commonly about 40 μeq/L less than in drainage lakes. This is due in part to the longer hydraulic detention time in seepage lakes, which allows slow sulfate reduction reactions more time to decrease lake sulfate concentration. Nitrate typically influences ANC during events such as snowmelt. Chloride concentrations are generally low, except in lakes impacted by road salt.

  6. An Optical Clock/Frequency Standard at 657 nm Based On Laser-Cooled Neutral Calcium

    NASA Astrophysics Data System (ADS)

    Oates, Chris

    2002-05-01

    Optical atomic clocks are receiving increased attention due to their enormous potential for high stability and accuracy, and because of the revolution in optical metrology that resulted from the development of fs-laser-based optical clockwork.(S. A. Diddams, T. Üdem, J. C. Bergquist, E. A. Curtis, R. E. Drullinger, L. Hollberg, W. M. Itano, W. D. Lee, C. W. Oates, K. R. Vogel, and D. J. Wineland, Science 293, 825 (2001).) We have constructed a high performance diode-laser-based optical frequency reference that uses an intercombination line (400 Hz natural linewidth) in laser-cooled neutral Ca at 657 nm. Absolute frequency measurements against the Cs-based NIST time ensemble via fs-laser metrology have led to a determination of the clock frequency (456 THz) with 26 Hz uncertainty.(T. Üdem, S. A. Diddams, K. R. Vogel, C. W. Oates, E. A. Curtis, W. D. Lee, W. M. Itano, R. E. Drullinger, J. C. Bergquist, and L. Hollberg, Phys. Rev. Lett. 86, 4996 (2001).) Measurements of the short-term fractional frequency instability against a Hg^+ ion optical clock system (again via the fs-laser comb) yielded an upper limit of 6x10-15 @ 1 s. In order to improve these results by an order of magnitude or more, we are currently developing a second-stage cooling scheme for Ca. This approach uses quenched cooling with the narrow clock transition and can reduce the atomic temperature by nearly three orders of magnitude. Recent cooling results in one and three dimensions will be presented.

  7. An anti-attack model based on complex network theory in P2P networks

    NASA Astrophysics Data System (ADS)

    Peng, Hao; Lu, Songnian; Zhao, Dandan; Zhang, Aixin; Li, Jianhua

    2012-04-01

    Complex network theory is a useful way to study many real systems. In this paper, an anti-attack model based on complex network theory is introduced. The mechanism of this model is based on a dynamic compensation process and a reverse percolation process in P2P networks. The main purpose of the paper is: (i) a dynamic compensation process can turn an attacked P2P network into a power-law (PL) network with exponential cutoff; (ii) a local healing process can restore the maximum degree of peers in an attacked P2P network to a normal level; (iii) a restoring process based on reverse percolation theory connects the fragmentary peers of an attacked P2P network together into a giant connected component. In this way, the model based on complex network theory can be effectively utilized for anti-attack and protection purposes in P2P networks.

  8. Global Exponential Stability of Almost Periodic Solution for Neutral-Type Cohen-Grossberg Shunting Inhibitory Cellular Neural Networks with Distributed Delays and Impulses

    PubMed Central

    Xu, Lijun; Jiang, Qi; Gu, Guodong

    2016-01-01

    A kind of neutral-type Cohen-Grossberg shunting inhibitory cellular neural networks with distributed delays and impulses is considered. Firstly, by using the theory of impulsive differential equations and the contracting mapping principle, the existence and uniqueness of the almost periodic solution for the above system are obtained. Secondly, by constructing a suitable Lyapunov functional, the global exponential stability of the unique almost periodic solution is also investigated. The work in this paper improves and extends some results in recent years. As an application, an example and numerical simulations are presented to demonstrate the feasibility and effectiveness of the main results. PMID:27190502

  9. Compact Interconnection Networks Based on Quantum Dots

    NASA Technical Reports Server (NTRS)

    Fijany, Amir; Toomarian, Nikzad; Modarress, Katayoon; Spotnitz, Matthew

    2003-01-01

    Architectures that would exploit the distinct characteristics of quantum-dot cellular automata (QCA) have been proposed for digital communication networks that connect advanced digital computing circuits. In comparison with networks of wires in conventional very-large-scale integrated (VLSI) circuitry, the networks according to the proposed architectures would be more compact. The proposed architectures would make it possible to implement complex interconnection schemes that are required for some advanced parallel-computing algorithms and that are difficult (and in many cases impractical) to implement in VLSI circuitry. The difficulty of implementation in VLSI and the major potential advantage afforded by QCA were described previously in Implementing Permutation Matrices by Use of Quantum Dots (NPO-20801), NASA Tech Briefs, Vol. 25, No. 10 (October 2001), page 42. To recapitulate: Wherever two wires in a conventional VLSI circuit cross each other and are required not to be in electrical contact with each other, there must be a layer of electrical insulation between them. This, in turn, makes it necessary to resort to a noncoplanar and possibly a multilayer design, which can be complex, expensive, and even impractical. As a result, much of the cost of designing VLSI circuits is associated with minimization of data routing and assignment of layers to minimize crossing of wires. Heretofore, these considerations have impeded the development of VLSI circuitry to implement complex, advanced interconnection schemes. On the other hand, with suitable design and under suitable operating conditions, QCA-based signal paths can be allowed to cross each other in the same plane without adverse effect. In principle, this characteristic could be exploited to design compact, coplanar, simple (relative to VLSI) QCA-based networks to implement complex, advanced interconnection schemes. The proposed architectures require two advances in QCA-based circuitry beyond basic QCA-based binary

  10. Operational characteristics in the three-phase transformer-type SFCL with neutral line based on sequential reclosing process

    NASA Astrophysics Data System (ADS)

    Cho, Y. S.; Choi, H. S.; Jung, B. I.

    2011-11-01

    In a transformer-type superconducting fault current limiter (SFCL) with a neutral line, which is connected between the superconducting elements and secondary windings, we verified that the SFCL has excellent characteristics that induce the perfect simultaneous quench of the superconducting elements in the previous study. The application of the SFCL to the power networks requires its coordination with the reclosing operation duty, which protects a circuit. In this study, the fault current limiting and recovery characteristics of superconducting elements in the three-phase transformer-type SFCL with the neutral line were analyzed. The limiting rate of the fault current in the transformer-type SFCL could increased by an iron core, which allows quenching of the superconducting elements in a sound phase as well as in a faulted phase. In addition, the simultaneous quench led to uniform burdens on superconducting elements, all of which recovered their superconducting state within an opening cycle of a circuit breaker. Thus, the transformer-type SFCL with the neutral line could reliably conduct the fault current limiting and recovery operations of superconducting elements according to the reclosing operation duty and fault types.

  11. Goal-based angular adaptivity applied to a wavelet-based discretisation of the neutral particle transport equation

    SciTech Connect

    Goffin, Mark A.; Buchan, Andrew G.; Dargaville, Steven; Pain, Christopher C.; Smith, Paul N.; Smedley-Stevenson, Richard P.

    2015-01-15

    A method for applying goal-based adaptive methods to the angular resolution of the neutral particle transport equation is presented. The methods are applied to an octahedral wavelet discretisation of the spherical angular domain which allows for anisotropic resolution. The angular resolution is adapted across both the spatial and energy dimensions. The spatial domain is discretised using an inner-element sub-grid scale finite element method. The goal-based adaptive methods optimise the angular discretisation to minimise the error in a specific functional of the solution. The goal-based error estimators require the solution of an adjoint system to determine the importance to the specified functional. The error estimators and the novel methods to calculate them are described. Several examples are presented to demonstrate the effectiveness of the methods. It is shown that the methods can significantly reduce the number of unknowns and computational time required to obtain a given error. The novelty of the work is the use of goal-based adaptive methods to obtain anisotropic resolution in the angular domain for solving the transport equation. -- Highlights: •Wavelet angular discretisation used to solve transport equation. •Adaptive method developed for the wavelet discretisation. •Anisotropic angular resolution demonstrated through the adaptive method. •Adaptive method provides improvements in computational efficiency.

  12. Curation-Based Network Marketing: Strategies for Network Growth and Electronic Word-of-Mouth Diffusion

    ERIC Educational Resources Information Center

    Church, Earnie Mitchell, Jr.

    2013-01-01

    In the last couple of years, a new aspect of online social networking has emerged, in which the strength of social network connections is based not on social ties but mutually shared interests. This dissertation studies these "curation-based" online social networks (CBN) and their suitability for the diffusion of electronic word-of-mouth…

  13. Efficient, Semitransparent Neutral-Colored Solar Cells Based on Microstructured Formamidinium Lead Trihalide Perovskite.

    PubMed

    Eperon, Giles E; Bryant, Daniel; Troughton, Joel; Stranks, Samuel D; Johnston, Michael B; Watson, Trystan; Worsley, David A; Snaith, Henry J

    2015-01-01

    Efficient, neutral-colored semitransparent solar cells are of commercial interest for incorporation into the windows and surfaces of buildings and automobiles. Here, we report on semitransparent perovskite solar cells that are both efficient and neutral-colored, even in full working devices. Using the microstructured architecture previously developed, we achieve higher efficiencies by replacing methylammonium lead iodide perovskite with formamidinium lead iodide. Current-voltage hysteresis is also much reduced. Furthermore, we apply a novel transparent cathode to the devices, enabling us to fabricate neutral-colored semitransparent full solar cells for the first time. Such devices demonstrate over 5% power conversion efficiency for average visible transparencies of almost 30%, retaining impressive color-neutrality. This makes these devices the best-performing single-junction neutral-colored semitransparent solar cells to date. These microstructured perovskite solar cells are shown to have a significant advantage over silicon solar cells in terms of performance at high incident angles of sunlight, making them ideal for building integration. PMID:26263101

  14. Optimal halftoning for network-based imaging

    NASA Astrophysics Data System (ADS)

    Ostromoukhov, Victor

    2000-12-01

    In this contribution, we introduce a multiple depth progressive representation for network-based still and moving images. A simple quantization algorithm associated with this representation provides optimal image quality. By optimum, we mean the best possible visual quality for a given value of information under real life constraints such as physical, psychological , or legal constraints. A special variant of the algorithm, multi-depth coherent error diffusion, addresses a specific problem of temporal coherence between frames in moving images. The output produced with our algorithm is visually pleasant because its Fourier spectrum is close to the 'blue noise'.

  15. Email user ranking based on email networks

    NASA Astrophysics Data System (ADS)

    Tran, Quang Anh; Vu, Minh Tuan; Frater, Michael; Jiang, Frank

    2012-09-01

    In this paper, four spam-filtering approaches based on the mail networks: Clustering, Extended Clustering Coefficient, PageRank Algorithm and Weighted PageRank Algorithm are analyzed. We also propose a couple of fully worked-out datasets against which the experimental comparisons with the respect to the accuracy of email user ranking and spam filtering are conducted. The results indicate that PageRank algorithm and Extended Clustering Coefficient approaches are better than others. The rate of true detection is over 99.5% while the failed alarm remains below 0.5%.

  16. Toxic effects of Al-based coagulants on Brassica chinensis and Raphanus sativus growing in acid and neutral conditions.

    PubMed

    Zhang, Kaisong; Zhou, Qixing

    2005-04-01

    The ecotoxicological effects of aluminum (Al)-based coagulants are of concern because of their wide-ranging applications in wastewater treatment and water purification. As important Al-based coagulants, AlCl(3) and PAC (polyaluminum-chloride) were selected as examples to examine the toxic effects on representative vegetables including the cabbage Brassica chinensis and the radish Raphanus sativus over a range of exposure concentrations in neutral (pH 7.00) and acidic (pH 4.00) conditions, using seed germination and root elongation in the early-growth stage as indicators of toxicity. The results showed that root elongation of the two vegetables was a more sensitive indicator than was seed germination for evaluating the toxicity of Al. As a single influencing factor, H(+) had no significant direct effects on root elongation of Brassica chinensis and Raphanus sativus under the experimental conditions. The toxicity of Al played the main role in inhibiting root elongation and seed germination and was strongly related to changes in pH. There was a markedly positive relationship between the inhibitory rate of root elongation, seed germination, and the concentration of Al at pH 4.00 (p < 0.01). The toxic effect of AlCl(3) on Brassica chinensis was less with a neutral pH than at pH 4.00, but Raphanus sativus was more susceptible to AlCl(3) toxicity at a neutral pH than at pH 4.00. Both Raphanus sativus and Brassica chinensis had a more toxic response to a low concentration (<64 mg . L(-1)) of PAC in a neutral condition than in an acidic condition. Undoubtedly, the Al toxicity caused by Al-based coagulants at a neutral pH is relevant when treatment solids are used in agriculture. PMID:15793823

  17. Theory of proton neutralization based on the Kleber-Zwiegel model of screening electron pickup

    NASA Astrophysics Data System (ADS)

    Kato, M.; Ohtsuki, Y.-H.

    1998-02-01

    The Kleber-Zwiegel (KZ) model for proton neutralization, in which some electron is picked up from the screening electron cloud around the proton, has been reformulated in terms of quantum field theory of solids. Using the reformulated KZ model, the cases of an Al (high electron density case) and a Cs (low electron density) metal are investigated within the Thomas-Fermi approximation for the screening effects. For high electron density metals, the resonant neutralization is a predominant process and it can be regarded as an electron pickup process from the screening electron cloud in the surface region. In contrast, for low electron density metals, it appears that the Auger neutralization, which is disregarded in the KZ model, cannot be neglected.

  18. A photodiode-based neutral particle bolometer for characterizing charge-exchanged fast-ion behavior.

    PubMed

    Clary, R; Smirnov, A; Dettrick, S; Knapp, K; Korepanov, S; Ruskov, E; Heidbrink, W W; Zhu, Y

    2012-10-01

    A neutral particle bolometer (NPB) has been designed and implemented on Tri Alpha Energy's C-2 device in order to spatially and temporally resolve the charge-exchange losses of fast-ion populations originating from neutral beam injection into field-reversed configuration plasmas. This instrument employs a silicon photodiode as the detection device with an integrated tungsten filter coating to reduce sensitivity to light radiation. Here we discuss the technical aspects and calibration of the NPB, and report typical NPB measurement results of wall recycling effects on fast-ion losses. PMID:23126887

  19. Experimental performance evaluation of software defined networking (SDN) based data communication networks for large scale flexi-grid optical networks.

    PubMed

    Zhao, Yongli; He, Ruiying; Chen, Haoran; Zhang, Jie; Ji, Yuefeng; Zheng, Haomian; Lin, Yi; Wang, Xinbo

    2014-04-21

    Software defined networking (SDN) has become the focus in the current information and communication technology area because of its flexibility and programmability. It has been introduced into various network scenarios, such as datacenter networks, carrier networks, and wireless networks. Optical transport network is also regarded as an important application scenario for SDN, which is adopted as the enabling technology of data communication networks (DCN) instead of general multi-protocol label switching (GMPLS). However, the practical performance of SDN based DCN for large scale optical networks, which is very important for the technology selection in the future optical network deployment, has not been evaluated up to now. In this paper we have built a large scale flexi-grid optical network testbed with 1000 virtual optical transport nodes to evaluate the performance of SDN based DCN, including network scalability, DCN bandwidth limitation, and restoration time. A series of network performance parameters including blocking probability, bandwidth utilization, average lightpath provisioning time, and failure restoration time have been demonstrated under various network environments, such as with different traffic loads and different DCN bandwidths. The demonstration in this work can be taken as a proof for the future network deployment. PMID:24787842

  20. Network model of bilateral power markets based on complex networks

    NASA Astrophysics Data System (ADS)

    Wu, Yang; Liu, Junyong; Li, Furong; Yan, Zhanxin; Zhang, Li

    2014-06-01

    The bilateral power transaction (BPT) mode becomes a typical market organization with the restructuring of electric power industry, the proper model which could capture its characteristics is in urgent need. However, the model is lacking because of this market organization's complexity. As a promising approach to modeling complex systems, complex networks could provide a sound theoretical framework for developing proper simulation model. In this paper, a complex network model of the BPT market is proposed. In this model, price advantage mechanism is a precondition. Unlike other general commodity transactions, both of the financial layer and the physical layer are considered in the model. Through simulation analysis, the feasibility and validity of the model are verified. At same time, some typical statistical features of BPT network are identified. Namely, the degree distribution follows the power law, the clustering coefficient is low and the average path length is a bit long. Moreover, the topological stability of the BPT network is tested. The results show that the network displays a topological robustness to random market member's failures while it is fragile against deliberate attacks, and the network could resist cascading failure to some extent. These features are helpful for making decisions and risk management in BPT markets.

  1. Fast surface design based on sketched networks

    NASA Astrophysics Data System (ADS)

    van Dijk, Casper G. C.

    1992-11-01

    Computer aided design of freeformed surfaces is strongly biased towards input and optimization of surfaces. Input modules are based on digitizing drawings or placing and manipulating spline control vertices. Design, especially during the idea generation (or conceptual) design phase, is poorly supported. We present a system based on direct manipulation of shaded images of the surfaces. The designer sketches profiles on a tablet. The profiles are positioned in object space with a spaceball (6D joystick). A network of crossing curves is built interactively. The system constructs patches over this network in realtime. The designer can correct a profile by sketching. The affected surfaces are updated immediately. Patches are defined by the curves and estimated cross-boundary derivatives. They connect with G1 continuity. Our prototype surface modeler avoids the need for exact dimensions and precise coordinates, as seen in traditional systems. Instead, it supports fast, intuitive generation and evaluation of surfaces. We discuss a comparison with other systems regarding the time needed to model shapes, and some opinions of professional industrial designers.

  2. UPM: unified policy-based network management

    NASA Astrophysics Data System (ADS)

    Law, Eddie; Saxena, Achint

    2001-07-01

    Besides providing network management to the Internet, it has become essential to offer different Quality of Service (QoS) to users. Policy-based management provides control on network routers to achieve this goal. The Internet Engineering Task Force (IETF) has proposed a two-tier architecture whose implementation is based on the Common Open Policy Service (COPS) protocol and Lightweight Directory Access Protocol (LDAP). However, there are several limitations to this design such as scalability and cross-vendor hardware compatibility. To address these issues, we present a functionally enhanced multi-tier policy management architecture design in this paper. Several extensions are introduced thereby adding flexibility and scalability. In particular, an intermediate entity between the policy server and policy rule database called the Policy Enforcement Agent (PEA) is introduced. By keeping internal data in a common format, using a standard protocol, and by interpreting and translating request and decision messages from multi-vendor hardware, this agent allows a dynamic Unified Information Model throughout the architecture. We have tailor-made this unique information system to save policy rules in the directory server and allow executions of policy rules with dynamic addition of new equipment during run-time.

  3. Paper-based synthetic gene networks.

    PubMed

    Pardee, Keith; Green, Alexander A; Ferrante, Tom; Cameron, D Ewen; DaleyKeyser, Ajay; Yin, Peng; Collins, James J

    2014-11-01

    Synthetic gene networks have wide-ranging uses in reprogramming and rewiring organisms. To date, there has not been a way to harness the vast potential of these networks beyond the constraints of a laboratory or in vivo environment. Here, we present an in vitro paper-based platform that provides an alternate, versatile venue for synthetic biologists to operate and a much-needed medium for the safe deployment of engineered gene circuits beyond the lab. Commercially available cell-free systems are freeze dried onto paper, enabling the inexpensive, sterile, and abiotic distribution of synthetic-biology-based technologies for the clinic, global health, industry, research, and education. For field use, we create circuits with colorimetric outputs for detection by eye and fabricate a low-cost, electronic optical interface. We demonstrate this technology with small-molecule and RNA actuation of genetic switches, rapid prototyping of complex gene circuits, and programmable in vitro diagnostics, including glucose sensors and strain-specific Ebola virus sensors. PMID:25417167

  4. Paper-based Synthetic Gene Networks

    PubMed Central

    Pardee, Keith; Green, Alexander A.; Ferrante, Tom; Cameron, D. Ewen; DaleyKeyser, Ajay; Yin, Peng; Collins, James J.

    2014-01-01

    Synthetic gene networks have wide-ranging uses in reprogramming and rewiring organisms. To date, there has not been a way to harness the vast potential of these networks beyond the constraints of a laboratory or in vivo environment. Here, we present an in vitro paper-based platform that provides a new venue for synthetic biologists to operate, and a much-needed medium for the safe deployment of engineered gene circuits beyond the lab. Commercially available cell-free systems are freeze-dried onto paper, enabling the inexpensive, sterile and abiotic distribution of synthetic biology-based technologies for the clinic, global health, industry, research and education. For field use, we create circuits with colorimetric outputs for detection by eye, and fabricate a low-cost, electronic optical interface. We demonstrate this technology with small molecule and RNA actuation of genetic switches, rapid prototyping of complex gene circuits, and programmable in vitro diagnostics, including glucose sensors and strain-specific Ebola virus sensors. PMID:25417167

  5. Mesh deformation based on artificial neural networks

    NASA Astrophysics Data System (ADS)

    Stadler, Domen; Kosel, Franc; Čelič, Damjan; Lipej, Andrej

    2011-09-01

    In the article a new mesh deformation algorithm based on artificial neural networks is introduced. This method is a point-to-point method, meaning that it does not use connectivity information for calculation of the mesh deformation. Two already known point-to-point methods, based on interpolation techniques, are also presented. In contrast to the two known interpolation methods, the new method does not require a summation over all boundary nodes for one displacement calculation. The consequence of this fact is a shorter computational time of mesh deformation, which is proven by different deformation tests. The quality of the deformed meshes with all three deformation methods was also compared. Finally, the generated and the deformed three-dimensional meshes were used in the computational fluid dynamics numerical analysis of a Francis water turbine. A comparison of the analysis results was made to prove the applicability of the new method in every day computation.

  6. Films based on neutralized chitosan citrate as innovative composition for cosmetic application.

    PubMed

    Libio, Illen C; Demori, Renan; Ferrão, Marco F; Lionzo, Maria I Z; da Silveira, Nádya P

    2016-10-01

    In this work, citrate and acetate buffers, were investigated as neutralizers to chitosan salts in order to provide biocompatible and stable films. To choose the appropriate film composition for this study, neutralized chitosan citrate and acetate films, with and without the plasticizer glycerol, were prepared and characterized by thickness, moisture content, degree of swelling, total soluble matter in acid medium, simultaneous thermal analysis and differential scanning calorimetry. Chitosan films neutralized in citrate buffer showed greater physical integrity resulted from greater thicknesses, lower moisture absorbance, lower tendency to solubility in the acid medium, and better swelling capacities. According to thermal analyses, these films had higher interaction with water which is considered an important feature for cosmetic application. Since the composition prepared in citrate buffer without glycerol was considered to present better physical integrity, it was applied to investigate hyaluronic acid release in a skin model. Skins treated with those films, with or without hyaluronic acid, show stratum corneum desquamation and hydration within 10min. The results suggest that the neutralized chitosan citrate film prepared without glycerol promotes a cosmetic effect for skin exfoliation in the presence or absence of hyaluronic acid. PMID:27287105

  7. Extending DIII-D Neutral Beam Modulated Operations with a Camac Based Total on Time Interlock

    SciTech Connect

    Baggest, D.S.; Broesch, J.D.; Phillips, J.C.

    1999-11-01

    A new total-on-time interlock has increased the operational time limits of the Neutral Beam systems at DIII-D. The interlock, called the Neutral Beam On-Time-Limiter (NBOTL), is a custom built CAMAC module utilizing a Xilinx 9572 Complex Programmable Logic Device (CPLD) as its primary circuit. The Neutral Beam Injection Systems are the primary source of auxiliary heating for DIII-D plasma discharges and contain eight sources capable of delivering 20MW of power. The delivered power is typically limited to 3.5 s per source to protect beam-line components, while a DIII-D plasma discharge usually exceeds 5 s. Implemented as a hardware interlock within the neutral beam power supplies, the NBOTL limits the beam injection time. With a continuing emphasis on modulated beam injections, the NBOTL guards against command faults and allows the beam injection to be safely spread over a longer plasma discharge time. The NBOTL design is an example of incorporating modern circuit design techniques (CPLD) within an established format (CAMAC). The CPLD is the heart of the NBOTL and contains 90% of the circuitry, including a loadable, 1 MHz, 28 bit, BCD count down timer, buffers, and CAMAC communication circuitry. This paper discusses the circuit design and implementation. Of particular interest is the melding of flexible modern programmable logic devices with the CAMAC format.

  8. Silane/iodine-based cleavage of esters and ethers under neutral conditions*

    PubMed Central

    Ho, Tse-Lok; Olah, George A.

    1978-01-01

    New, efficient cleavage of carboxylic esters with iodotrimethylsilane or a mixture of phenyltrimethylsilane and iodine is described. Essentially neutral conditions can be maintained throughout the reactions. Ethers can be dealkylated by the latter method in high yields. The mechanism of the cleavage reactions is considered to include six-membered ring homopolar transition states. PMID:16592482

  9. Rapid assessment of antibody-induced ricin neutralization by employing a novel functional cell-based assay.

    PubMed

    Gal, Yoav; Alcalay, Ron; Sabo, Tamar; Noy-Porat, Tal; Epstein, Eyal; Kronman, Chanoch; Mazor, Ohad

    2015-09-01

    Ricin is one of the most potent and lethal toxins known against which there is no available antidote. Currently, the most promising countermeasures against the toxin are based on neutralizing antibodies elicited by active vaccination or administered passively. A cell-based assay is widely applied for the primary screening and evaluation of anti-ricin antibodies, yet such assays are usually time-consuming (18-72 h). Here, we report of a novel assay to monitor ricin activity, based on HeLa cells that stably express the rapidly-degraded ubiquitin-luciferase (Ub-FL, half-life of 2 min). Ricin-induced arrest of protein synthesis could be quantified within 3 to 6h post intoxication (IC90 of 300 and 100 ng/ml, respectively). Furthermore, by stabilizing the intracellular levels of Ub-FL in the last hour of the assay, a 3-fold increase in the assay sensitivity was attained. We applied this assay to monitor the efficacy of a ricin holotoxin-based vaccine by measuring the formation of neutralizing antibodies throughout the immunization course. The potency of anti-ricin monoclonal antibodies (directed to either subunit of the toxin) could also be easily and accurately measured in this assay format. Owing to its simplicity, this assay may be implemented for high-throughput screening of ricin-neutralizing antibodies and for identification of small-molecule inhibitors of the toxin, as well as other ribosome-inactivating toxins. PMID:26003675

  10. Rumor diffusion in an interests-based dynamic social network.

    PubMed

    Tang, Mingsheng; Mao, Xinjun; Guessoum, Zahia; Zhou, Huiping

    2013-01-01

    To research rumor diffusion in social friend network, based on interests, a dynamic friend network is proposed, which has the characteristics of clustering and community, and a diffusion model is also proposed. With this friend network and rumor diffusion model, based on the zombie-city model, some simulation experiments to analyze the characteristics of rumor diffusion in social friend networks have been conducted. The results show some interesting observations: (1) positive information may evolve to become a rumor through the diffusion process that people may modify the information by word of mouth; (2) with the same average degree, a random social network has a smaller clustering coefficient and is more beneficial for rumor diffusion than the dynamic friend network; (3) a rumor is spread more widely in a social network with a smaller global clustering coefficient than in a social network with a larger global clustering coefficient; and (4) a network with a smaller clustering coefficient has a larger efficiency. PMID:24453911

  11. Rumor Diffusion in an Interests-Based Dynamic Social Network

    PubMed Central

    Mao, Xinjun; Guessoum, Zahia; Zhou, Huiping

    2013-01-01

    To research rumor diffusion in social friend network, based on interests, a dynamic friend network is proposed, which has the characteristics of clustering and community, and a diffusion model is also proposed. With this friend network and rumor diffusion model, based on the zombie-city model, some simulation experiments to analyze the characteristics of rumor diffusion in social friend networks have been conducted. The results show some interesting observations: (1) positive information may evolve to become a rumor through the diffusion process that people may modify the information by word of mouth; (2) with the same average degree, a random social network has a smaller clustering coefficient and is more beneficial for rumor diffusion than the dynamic friend network; (3) a rumor is spread more widely in a social network with a smaller global clustering coefficient than in a social network with a larger global clustering coefficient; and (4) a network with a smaller clustering coefficient has a larger efficiency. PMID:24453911

  12. Enhanced dissolution and oral bioavailability of aripiprazole nanosuspensions prepared by nanoprecipitation/homogenization based on acid-base neutralization.

    PubMed

    Xu, Ying; Liu, Xiaoyi; Lian, Ruyue; Zheng, Siji; Yin, Zongning; Lu, Yi; Wu, Wei

    2012-11-15

    In this study, aripiprazole (APZ), a weak alkaline drug with pH-dependent solubility, was selected as model drug to examine the feasibility of preparing nanosuspensions using nanoprecipitation/homogenization technique based on acid-base neutralization. The related substances in nanosuspensions prepared under optimal conditions were slightly increased as compared with APZ raw material. The resultant APZ nanosuspensions showed a mean particle size of 350 nm with polydispersion index (PI) value of 0.20. Good physical stability was kept for over 40 days. SEM observation showed the morphology of oval crystals with rough surface. Nanosuspensions significantly increased the solubility as well as the dissolution of APZ due to the decreased particle size. Differential scanning calorimetry and powder X-ray diffractometry confirmed the crystallinity of APZ in nanosuspensions. APZ nanosuspensions got maximum absorption rate and extent comparing with APZ commercial tablet and suspensions with relative bioavailability of 123.43 ± 12.98% and 171.41 ± 14.62%, respectively. This technique has the potential to prepare nanosuspensions of insoluble drugs with pH-dependent solubility. PMID:22989976

  13. ALEX neutral beam probe

    SciTech Connect

    Pourrezaei, K.

    1982-01-01

    A neutral beam probe capable of measuring plasma space potential in a fully 3-dimensional magnetic field geometry has been developed. This neutral beam was successfully used to measure an arc target plasma contained within the ALEX baseball magnetic coil. A computer simulation of the experiment was performed to refine the experimental design and to develop a numerical model for scaling the ALEX neutral beam probe to other cases of fully 3-dimensional magnetic field. Based on this scaling a 30 to 50 keV neutral cesium beam probe capable of measuring space potential in the thermal barrier region of TMX Upgrade was designed.

  14. DEM interpolation based on artificial neural networks

    NASA Astrophysics Data System (ADS)

    Jiao, Limin; Liu, Yaolin

    2005-10-01

    This paper proposed a systemic resolution scheme of Digital Elevation model (DEM) interpolation based on Artificial Neural Networks (ANNs). In this paper, we employ BP network to fit terrain surface, and then detect and eliminate the samples with gross errors. This paper uses Self-organizing Feature Map (SOFM) to cluster elevation samples. The study area is divided into many more homogenous tiles after clustering. BP model is employed to interpolate DEM in each cluster. Because error samples are eliminated and clusters are built, interpolation result is better. The case study indicates that ANN interpolation scheme is feasible. It also shows that ANN can get a more accurate result by comparing ANN with polynomial and spline interpolation. ANN interpolation doesn't need to determine the interpolation function beforehand, so manmade influence is lessened. The ANN interpolation is more automatic and intelligent. At the end of the paper, we propose the idea of constructing ANN surface model. This model can be used in multi-scale DEM visualization, and DEM generalization, etc.

  15. Network video transmission system based on SOPC

    NASA Astrophysics Data System (ADS)

    Zhang, Zhengbing; Deng, Huiping; Xia, Zhenhua

    2008-03-01

    Video systems have been widely used in many fields such as conferences, public security, military affairs and medical treatment. With the rapid development of FPGA, SOPC has been paid great attentions in the area of image and video processing in recent years. A network video transmission system based on SOPC is proposed in this paper for the purpose of video acquisition, video encoding and network transmission. The hardware platform utilized to design the system is an SOPC board of model Altera's DE2, which includes an FPGA chip of model EP2C35F672C6, an Ethernet controller and a video I/O interface. An IP core, known as Nios II embedded processor, is used as the CPU of the system. In addition, a hardware module for format conversion of video data, and another module to realize Motion-JPEG have been designed with Verilog HDL. These two modules are attached to the Nios II processor as peripheral equipments through the Avalon bus. Simulation results show that these two modules work as expected. Uclinux including TCP/IP protocol as well as the driver of Ethernet controller is chosen as the embedded operating system and an application program scheme is proposed.

  16. Medical education practice-based research networks: Facilitating collaborative research

    PubMed Central

    Schwartz, Alan; Young, Robin; Hicks, Patricia J.; APPD LEARN, For

    2016-01-01

    Abstract Background: Research networks formalize and institutionalize multi-site collaborations by establishing an infrastructure that enables network members to participate in research, propose new studies, and exploit study data to move the field forward. Although practice-based clinical research networks are now widespread, medical education research networks are rapidly emerging. Aims: In this article, we offer a definition of the medical education practice-based research network, a brief description of networks in existence in July 2014 and their features, and a more detailed case study of the emergence and early growth of one such network, the Association of Pediatric Program Directors Longitudinal Educational Assessment Research Network (APPD LEARN). Methods: We searched for extant networks through peer-reviewed literature and the world-wide web. Results: We identified 15 research networks in medical education founded since 2002 with membership ranging from 8 to 120 programs. Most focus on graduate medical education in primary care or emergency medicine specialties. Conclusions: We offer four recommendations for the further development and spread of medical education research networks: increasing faculty development, obtaining central resources, studying networks themselves, and developing networks of networks. PMID:25319404

  17. Cluster and propensity based approximation of a network

    PubMed Central

    2013-01-01

    Background The models in this article generalize current models for both correlation networks and multigraph networks. Correlation networks are widely applied in genomics research. In contrast to general networks, it is straightforward to test the statistical significance of an edge in a correlation network. It is also easy to decompose the underlying correlation matrix and generate informative network statistics such as the module eigenvector. However, correlation networks only capture the connections between numeric variables. An open question is whether one can find suitable decompositions of the similarity measures employed in constructing general networks. Multigraph networks are attractive because they support likelihood based inference. Unfortunately, it is unclear how to adjust current statistical methods to detect the clusters inherent in many data sets. Results Here we present an intuitive and parsimonious parametrization of a general similarity measure such as a network adjacency matrix. The cluster and propensity based approximation (CPBA) of a network not only generalizes correlation network methods but also multigraph methods. In particular, it gives rise to a novel and more realistic multigraph model that accounts for clustering and provides likelihood based tests for assessing the significance of an edge after controlling for clustering. We present a novel Majorization-Minimization (MM) algorithm for estimating the parameters of the CPBA. To illustrate the practical utility of the CPBA of a network, we apply it to gene expression data and to a bi-partite network model for diseases and disease genes from the Online Mendelian Inheritance in Man (OMIM). Conclusions The CPBA of a network is theoretically appealing since a) it generalizes correlation and multigraph network methods, b) it improves likelihood based significance tests for edge counts, c) it directly models higher-order relationships between clusters, and d) it suggests novel clustering

  18. Cooperative UAV-Based Communications Backbone for Sensor Networks

    SciTech Connect

    Roberts, R S

    2001-10-07

    The objective of this project is to investigate the use of unmanned air vehicles (UAVs) as mobile, adaptive communications backbones for ground-based sensor networks. In this type of network, the UAVs provide communication connectivity to sensors that cannot communicate with each other because of terrain, distance, or other geographical constraints. In these situations, UAVs provide a vertical communication path for the sensors, thereby mitigating geographic obstacles often imposed on networks. With the proper use of UAVs, connectivity to a widely disbursed sensor network in rugged terrain is readily achieved. Our investigation has focused on networks where multiple cooperating UAVs are used to form a network backbone. The advantage of using multiple UAVs to form the network backbone is parallelization of sensor connectivity. Many widely spaced or isolated sensors can be connected to the network at once using this approach. In these networks, the UAVs logically partition the sensor network into sub-networks (subnets), with one UAV assigned per subnet. Partitioning the network into subnets allows the UAVs to service sensors in parallel thereby decreasing the sensor-to-network connectivity. A UAV services sensors in its subnet by flying a route (path) through the subnet, uplinking data collected by the sensors, and forwarding the data to a ground station. An additional advantage of using multiple UAVs in the network is that they provide redundancy in the communications backbone, so that the failure of a single UAV does not necessarily imply the loss of the network.

  19. Facilitating the Development of School-Based Learning Networks

    ERIC Educational Resources Information Center

    Kubiak, Chris; Bertram, Joan

    2010-01-01

    Purpose: This paper aims to contribute to the knowledge base on leading and facilitating the growth of school improvement networks by describing the activities and challenges faced by network leaders. Design/methodology/approach: A total of 19 co-leaders from 12 networks were interviewed using a semi-structured schedule about the growth of their…

  20. Survey-Based Measurement of Public Management and Policy Networks

    ERIC Educational Resources Information Center

    Henry, Adam Douglas; Lubell, Mark; McCoy, Michael

    2012-01-01

    Networks have become a central concept in the policy and public management literature; however, theoretical development is hindered by a lack of attention to the empirical properties of network measurement methods. This paper compares three survey-based methods for measuring organizational networks: the roster, the free-recall name generator, and…

  1. Frequency-Based Investigation of Charge Neutralization Processes and Thermal Cavity Expansion in Gyrotrons

    NASA Astrophysics Data System (ADS)

    Schlaich, Andreas; Wu, Chuanren; Pagonakis, Ioannis; Avramidis, Konstantinos; Illy, Stefan; Gantenbein, Gerd; Jelonnek, John; Thumm, Manfred

    2015-09-01

    During the first hundred milliseconds, the frequency and RF output power of long pulse operating gyrotrons undergo deterministic variation. This well-known behavior is caused by the thermal expansion of the cavity and internal electrostatic processes related to the ionization of residual gas. A macroscopic analytical investigation of the gas conditions in modern gyrotrons indicates that ionization processes are unlikely to influence the overall internal gas pressure. In combination with electrostatic potential considerations, it was found that the beam depression voltage is not fully neutralized; in the case of W7-X gyrotrons, a maximum value of about 60 % neutralization is expected, in conflict with the common assumption of full neutralization in steady state. Using experimentally measured frequency shifts and the Evridiki gyrotron interaction simulation code, a fitting process was employed to further investigate these effects. The results are in very good agreement with the theoretical predictions and allow a separation of the time constants of the two processes causing the frequency tuning.

  2. Networks.

    ERIC Educational Resources Information Center

    Maughan, George R.; Petitto, Karen R.; McLaughlin, Don

    2001-01-01

    Describes the connectivity features and options of modern campus communication and information system networks, including signal transmission (wire-based and wireless), signal switching, convergence of networks, and network assessment variables, to enable campus leaders to make sound future-oriented decisions. (EV)

  3. Development and evaluation of a new immunohistochemistry-based test for the detection of rabies virus neutralizing antibodies

    PubMed Central

    Madhusudana, Shampur N; Malavalli, Bhavana V; Thankappan, Ullas P; Sundramoorthy, Subha; Belludi, Ashwin Y; Pulagumbaly, Srinivasa B; Sanyal, Sampada

    2014-01-01

    Rabies claims about 55 000 human lives and many hundreds of thousands of livestock every year, worldwide. Despite a heavy disease burden, laboratory facilities to diagnose the infection remain scarce in most countries of the developing world where the disease is endemic. Rapid Fluorescent Focus Inhibition Test (RFFIT) and Fluorescent Antibody Virus Neutralization Test (FAVN) are the common tests done in the rabies diagnostic laboratories to detect and quantitate Rabies Virus Neutralizing Antibodies (RVNA). RFFIT is most often employed in confirming seroconversion following prophylactic vaccination, and to aid ante-mortem diagnosis in suspected cases of rabies. Though this remains one of the most sought-after diagnostic services in rabies laboratories, the requirements for expensive anti-rabies fluorochrome antibody conjugate and a fluorescent microscope restrict its performance to only a few reference laboratories. Cost-effective laboratory diagnostic methods employing affordable technology are a need of the hour in the rabies-endemic countries. In this study we have developed a new immunohistochemistry-based neutralization test and extensively evaluated it along with RFFIT. One hundred and 20 human serum samples collected after post-exposure vaccination were subjected to both the tests for determining RVNA titers. The results obtained with the new test correlated significantly with those of RFFIT. Further validation of the inter- and intra- assay precision, lower limit of quantification (LLOQ) and specificity was also performed. The best correlation between the 2 methods, however, was observed only when the RVNA concentrations in the samples were >20 IU/mL. Overall, the immunohistrochemistry-based neutralization test yielded satisfactory results. We suggest that it might serve as a cost-effective alternative to RFFIT in low-resource settings in the developing countries. PMID:24583787

  4. Development and evaluation of a new immunohistochemistry-based test for the detection of rabies virus neutralizing antibodies.

    PubMed

    Madhusudana, Shampur N; Malavalli, Bhavana V; Thankappan, Ullas P; Sundramoorthy, Subha; Belludi, Ashwin Y; Pulagumbaly, Srinivasa B; Sanyal, Sampada

    2014-01-01

    Rabies claims about 55,000 human lives and many hundreds of thousands of livestock every year, worldwide. Despite a heavy disease burden, laboratory facilities to diagnose the infection remain scarce in most countries of the developing world where the disease is endemic. Rapid Fluorescent Focus Inhibition Test (RFFIT) and Fluorescent Antibody Virus Neutralization Test (FAVN) are the common tests done in the rabies diagnostic laboratories to detect and quantitate Rabies Virus Neutralizing Antibodies (RVNA). RFFIT is most often employed in confirming seroconversion following prophylactic vaccination, and to aid ante-mortem diagnosis in suspected cases of rabies. Though this remains one of the most sought-after diagnostic services in rabies laboratories, the requirements for expensive anti-rabies fluorochrome antibody conjugate and a fluorescent microscope restrict its performance to only a few reference laboratories. Cost-effective laboratory diagnostic methods employing affordable technology are a need of the hour in the rabies-endemic countries. In this study we have developed a new immunohistochemistry-based neutralization test and extensively evaluated it along with RFFIT. One hundred and 20 human serum samples collected after post-exposure vaccination were subjected to both the tests for determining RVNA titers. The results obtained with the new test correlated significantly with those of RFFIT. Further validation of the inter- and intra- assay precision, lower limit of quantification (LLOQ) and specificity was also performed. The best correlation between the 2 methods, however, was observed only when the RVNA concentrations in the samples were>20 IU/mL. Overall, the immunohistrochemistry-based neutralization test yielded satisfactory results. We suggest that it might serve as a cost-effective alternative to RFFIT in low-resource settings in the developing countries. PMID:24583787

  5. Syntheses and structural characterization of mercury (II) coordination polymers with neutral bidentate flexible pyrazole-based ligands

    NASA Astrophysics Data System (ADS)

    Lalegani, Arash; Khaledi Sardashti, Mohammad; Salavati, Hossein; Asadi, Amin; Gajda, Roman; Woźniak, Krzysztof

    2016-03-01

    Mercury(II) coordination compounds [Hg(μ-bbd)(μ-SCN)4]n(1) and [Hg(bpp)(SCN)2] (2) were synthesized by using the neutral flexible bidentate N-donor ligands 1,4-bis(3,5-dimethypyrazol-1-yl)butane (bbd) and 1,3-bis(3,5-dimethylpyrazolyl)propane (bpp), NCS- ligand and appropriate mercury(II) salts. Compound 1 forms a polymeric network with moieties which are connected by SCN groups and the mercury ions present as HgN3S2 trigonal bipyramides. The crystal structure of 2 is build of monomers and the mercury(II) ion adopts an HgN2S2 tetrahedral geometry. In the complex 1, each bbd acts as bridging ligand connecting Hg(μ-SCN)4 ions, while in the complex 2, the bpp ligand is coordinated to an mercury(II) ion in a cyclic-bidentate fashion forming an eight-membered metallocyclic ring. Moreover, in the tetrahedral structure of 2, the neutral molecules form a 1D chain structure through the C-H···N hydrogen bonds, whereas in 1 no hydrogen bonds are observed. Coordination compounds 1 and 2 have been characterized by infrared spectroscopy, elemental analyses and single-crystal X-ray diffraction.

  6. Semantic segmentation based on neural network and Bayesian network

    NASA Astrophysics Data System (ADS)

    Ge, Wenying; Liu, Guoying

    2013-10-01

    It is rather difficult for low-level visual features to describe the need for specific applications of image understanding, which results in the inconsistency between vision information and application need. In this paper, a new model is proposed to reduce this gap by combining low-level visual features with semantic features. It uses the output of neural network as the semantic feature, which is accompanied with the priori label features to describe the image after making normalization. And then, the proposed method employs Potts to model the distribution of label priori, and utilizes the Bayesian network to classify images. Several experiments on both synthetic and real images have verified that this method can get more accurate segmentation.

  7. Hierarchical coefficient of a multifractal based network

    NASA Astrophysics Data System (ADS)

    Moreira, Darlan A.; Lucena, Liacir dos Santos; Corso, Gilberto

    2014-02-01

    The hierarchical property for a general class of networks stands for a power-law relation between clustering coefficient, CC and connectivity k: CC∝kβ. This relation is empirically verified in several biologic and social networks, as well as in random and deterministic network models, in special for hierarchical networks. In this work we show that the hierarchical property is also present in a Lucena network. To create a Lucena network we use the dual of a multifractal lattice ML, the vertices are the sites of the ML and links are established between neighbouring lattices, therefore this network is space filling and planar. Besides a Lucena network shows a scale-free distribution of connectivity. We deduce a relation for the maximal local clustering coefficient CCimax of a vertex i in a planar graph. This condition expresses that the number of links among neighbour, N△, of a vertex i is equal to its connectivity ki, that means: N△=ki. The Lucena network fulfils the condition N△≃ki independent of ki and the anisotropy of ML. In addition, CCmax implies the threshold β=1 for the hierarchical property for any scale-free planar network.

  8. Performance analysis of electronic code division multiple access based virtual private networks over passive optical networks

    NASA Astrophysics Data System (ADS)

    Nadarajah, Nishaanthan; Nirmalathas, Ampalavanapillai

    2008-03-01

    A solution for implementing multiple secure virtual private networks over a passive optical network using electronic code division multiple access is proposed and experimentally demonstrated. The multiple virtual private networking capability is experimentally demonstrated with 40 Mb/s data multiplexed with a 640 Mb/s electronic code that is unique to each of the virtual private networks in the passive optical network, and the transmission of the electronically coded data is carried out using Fabry-Perot laser diodes. A theoretical scalability analysis for electronic code division multiple access based virtual private networks over a passive optical network is also carried out to identify the performance limits of the scheme. Several sources of noise such as optical beat interference and multiple access interference that are present in the receiver are considered with different operating system parameters such as transmitted optical power, spectral width of the broadband optical source, and processing gain to study the scalability of the network.

  9. Network-based production quality control

    NASA Astrophysics Data System (ADS)

    Kwon, Yongjin; Tseng, Bill; Chiou, Richard

    2007-09-01

    This study investigates the feasibility of remote quality control using a host of advanced automation equipment with Internet accessibility. Recent emphasis on product quality and reduction of waste stems from the dynamic, globalized and customer-driven market, which brings opportunities and threats to companies, depending on the response speed and production strategies. The current trends in industry also include a wide spread of distributed manufacturing systems, where design, production, and management facilities are geographically dispersed. This situation mandates not only the accessibility to remotely located production equipment for monitoring and control, but efficient means of responding to changing environment to counter process variations and diverse customer demands. To compete under such an environment, companies are striving to achieve 100%, sensor-based, automated inspection for zero-defect manufacturing. In this study, the Internet-based quality control scheme is referred to as "E-Quality for Manufacturing" or "EQM" for short. By its definition, EQM refers to a holistic approach to design and to embed efficient quality control functions in the context of network integrated manufacturing systems. Such system let designers located far away from the production facility to monitor, control and adjust the quality inspection processes as production design evolves.

  10. Automation of Network-Based Scientific Workflows

    SciTech Connect

    Altintas, I.; Barreto, R.; Blondin, J. M.; Cheng, Z.; Critchlow, T.; Khan, A.; Klasky, Scott A; Ligon, J.; Ludaescher, B.; Mouallem, P. A.; Parker, S.; Podhorszki, Norbert; Shoshani, A.; Silva, C.; Vouk, M. A.

    2007-01-01

    Comprehensive, end-to-end, data and workflow management solutions are needed to handle the increasing complexity of processes and data volumes associated with modern distributed scientific problem solving, such as ultra-scale simulations and high-throughput experiments. The key to the solution is an integrated network-based framework that is functional, dependable, fault-tolerant, and supports data and process provenance. Such a framework needs to make development and use of application workflows dramatically easier so that scientists' efforts can shift away from data management and utility software development to scientific research and discovery An integrated view of these activities is provided by the notion of scientific workflows - a series of structured activities and computations that arise in scientific problem-solving. An information technology framework that supports scientific workflows is the Ptolemy II based environment called Kepler. This paper discusses the issues associated with practical automation of scientific processes and workflows and illustrates this with workflows developed using the Kepler framework and tools.

  11. A neural networks-based hybrid routing protocol for wireless mesh networks.

    PubMed

    Kojić, Nenad; Reljin, Irini; Reljin, Branimir

    2012-01-01

    The networking infrastructure of wireless mesh networks (WMNs) is decentralized and relatively simple, but they can display reliable functioning performance while having good redundancy. WMNs provide Internet access for fixed and mobile wireless devices. Both in urban and rural areas they provide users with high-bandwidth networks over a specific coverage area. The main problems affecting these networks are changes in network topology and link quality. In order to provide regular functioning, the routing protocol has the main influence in WMN implementations. In this paper we suggest a new routing protocol for WMN, based on good results of a proactive and reactive routing protocol, and for that reason it can be classified as a hybrid routing protocol. The proposed solution should avoid flooding and creating the new routing metric. We suggest the use of artificial logic-i.e., neural networks (NNs). This protocol is based on mobile agent technologies controlled by a Hopfield neural network. In addition to this, our new routing metric is based on multicriteria optimization in order to minimize delay and blocking probability (rejected packets or their retransmission). The routing protocol observes real network parameters and real network environments. As a result of artificial logic intelligence, the proposed routing protocol should maximize usage of network resources and optimize network performance. PMID:22969360

  12. A Neural Networks-Based Hybrid Routing Protocol for Wireless Mesh Networks

    PubMed Central

    Kojić, Nenad; Reljin, Irini; Reljin, Branimir

    2012-01-01

    The networking infrastructure of wireless mesh networks (WMNs) is decentralized and relatively simple, but they can display reliable functioning performance while having good redundancy. WMNs provide Internet access for fixed and mobile wireless devices. Both in urban and rural areas they provide users with high-bandwidth networks over a specific coverage area. The main problems affecting these networks are changes in network topology and link quality. In order to provide regular functioning, the routing protocol has the main influence in WMN implementations. In this paper we suggest a new routing protocol for WMN, based on good results of a proactive and reactive routing protocol, and for that reason it can be classified as a hybrid routing protocol. The proposed solution should avoid flooding and creating the new routing metric. We suggest the use of artificial logic—i.e., neural networks (NNs). This protocol is based on mobile agent technologies controlled by a Hopfield neural network. In addition to this, our new routing metric is based on multicriteria optimization in order to minimize delay and blocking probability (rejected packets or their retransmission). The routing protocol observes real network parameters and real network environments. As a result of artificial logic intelligence, the proposed routing protocol should maximize usage of network resources and optimize network performance. PMID:22969360

  13. Interdependent Multi-Layer Networks: Modeling and Survivability Analysis with Applications to Space-Based Networks

    PubMed Central

    Castet, Jean-Francois; Saleh, Joseph H.

    2013-01-01

    This article develops a novel approach and algorithmic tools for the modeling and survivability analysis of networks with heterogeneous nodes, and examines their application to space-based networks. Space-based networks (SBNs) allow the sharing of spacecraft on-orbit resources, such as data storage, processing, and downlink. Each spacecraft in the network can have different subsystem composition and functionality, thus resulting in node heterogeneity. Most traditional survivability analyses of networks assume node homogeneity and as a result, are not suited for the analysis of SBNs. This work proposes that heterogeneous networks can be modeled as interdependent multi-layer networks, which enables their survivability analysis. The multi-layer aspect captures the breakdown of the network according to common functionalities across the different nodes, and it allows the emergence of homogeneous sub-networks, while the interdependency aspect constrains the network to capture the physical characteristics of each node. Definitions of primitives of failure propagation are devised. Formal characterization of interdependent multi-layer networks, as well as algorithmic tools for the analysis of failure propagation across the network are developed and illustrated with space applications. The SBN applications considered consist of several networked spacecraft that can tap into each other's Command and Data Handling subsystem, in case of failure of its own, including the Telemetry, Tracking and Command, the Control Processor, and the Data Handling sub-subsystems. Various design insights are derived and discussed, and the capability to perform trade-space analysis with the proposed approach for various network characteristics is indicated. The select results here shown quantify the incremental survivability gains (with respect to a particular class of threats) of the SBN over the traditional monolith spacecraft. Failure of the connectivity between nodes is also examined, and the

  14. NEUTRAL INTERSTELLAR HELIUM PARAMETERS BASED ON IBEX-Lo OBSERVATIONS AND TEST PARTICLE CALCULATIONS

    SciTech Connect

    Bzowski, M.; Kubiak, M. A.; Sokol, J. M.; Hlond, M.; Moebius, E.; Bochsler, P.; Leonard, T.; Heirtzler, D.; Kucharek, H.; Schwadron, N. A.; Crew, G. B.; Fuselier, S. A.; McComas, D. J.

    2012-02-01

    Because of its high ionization potential and weak interaction with hydrogen, neutral interstellar helium (NISHe) is almost unaffected at the heliospheric interface with the interstellar medium and freely enters the solar system. This second most abundant species provides some of the best information on the characteristics of the interstellar gas in the local interstellar cloud. The Interstellar Boundary Explorer (IBEX) is the second mission to directly detect NISHe. We present a comparison between recent IBEX NISHe observations and simulations carried out using a well-tested quantitative simulation code. Simulation and observation results compare well for times when measured fluxes are dominated by NISHe (and contributions from other species are small). Differences between simulations and observations indicate a previously undetected secondary population of neutral helium, likely produced by interaction of interstellar helium with plasma in the outer heliosheath. Interstellar neutral parameters are statistically different from previous in situ results obtained mostly from the GAS/Ulysses experiment, but they do agree with the local interstellar flow vector obtained from studies of interstellar absorption: the newly established flow direction is ecliptic longitude 79.{sup 0}2, latitude -5.{sup 0}1, the velocity is {approx}22.8 km s{sup -1}, and the temperature is 6200 K. These new results imply a markedly lower absolute velocity of the gas and thus significantly lower dynamic pressure on the boundaries of the heliosphere and different orientation of the Hydrogen Deflection Plane compared to prior results from Ulysses. A different orientation of this plane also suggests a new geometry of the interstellar magnetic field, and the lower dynamic pressure calls for a compensation by other components of the pressure balance, most likely a higher density of interstellar plasma and strength of interstellar magnetic field.

  15. Neural network based system for equipment surveillance

    DOEpatents

    Vilim, R.B.; Gross, K.C.; Wegerich, S.W.

    1998-04-28

    A method and system are disclosed for performing surveillance of transient signals of an industrial device to ascertain the operating state. The method and system involves the steps of reading into a memory training data, determining neural network weighting values until achieving target outputs close to the neural network output. If the target outputs are inadequate, wavelet parameters are determined to yield neural network outputs close to the desired set of target outputs and then providing signals characteristic of an industrial process and comparing the neural network output to the industrial process signals to evaluate the operating state of the industrial process. 33 figs.

  16. Neural network based system for equipment surveillance

    DOEpatents

    Vilim, Richard B.; Gross, Kenneth C.; Wegerich, Stephan W.

    1998-01-01

    A method and system for performing surveillance of transient signals of an industrial device to ascertain the operating state. The method and system involves the steps of reading into a memory training data, determining neural network weighting values until achieving target outputs close to the neural network output. If the target outputs are inadequate, wavelet parameters are determined to yield neural network outputs close to the desired set of target outputs and then providing signals characteristic of an industrial process and comparing the neural network output to the industrial process signals to evaluate the operating state of the industrial process.

  17. Development of a Triple-Color Pseudovirion-Based Assay to Detect Neutralizing Antibodies against Human Papillomavirus

    PubMed Central

    Nie, Jianhui; Liu, Yangyang; Huang, Weijin; Wang, Youchun

    2016-01-01

    Pseudovirion-based neutralization assay is considered the gold standard method for evaluating the immune response to human papillomavirus (HPV) vaccines. In this study, we developed a multicolor neutralization assay to simultaneously detect the neutralizing antibodies against different HPV types. FluoroSpot was used to interpret the fluorescent protein expression instead of flow cytometry. The results of FluoroSpot and flow cytometry showed good consistency, with R2 > 0.98 for the log-transformed IC50 values. Regardless of the reporter color, the single-, dual-, and triple-color neutralization assays reported identical results for the same samples. In low-titer samples from naturally HPV-infected individuals, there was strong agreement between the single- and triple-color assays, with kappa scores of 0.92, 0.89, and 0.96 for HPV16, HPV18, and HPV58, respectively. Good reproducibility was observed for the triple-color assay, with coefficients of variation of 2.0%–41.5% within the assays and 8.3%–36.2% between the assays. Three triple-color systems, HPV16-18-58, HPV6-33-45, and HPV11-31-52, were developed that could evaluate the immunogenicity of a nonavalent vaccine in three rounds of the assay. With the advantages of an easy-to-use procedure and less sample consumption, the multiple-color assay is more suitable than classical assays for large sero-epidemiological studies and clinical trials and is more amenable to automation. PMID:27120611

  18. Development of a Triple-Color Pseudovirion-Based Assay to Detect Neutralizing Antibodies against Human Papillomavirus.

    PubMed

    Nie, Jianhui; Liu, Yangyang; Huang, Weijin; Wang, Youchun

    2016-04-01

    Pseudovirion-based neutralization assay is considered the gold standard method for evaluating the immune response to human papillomavirus (HPV) vaccines. In this study, we developed a multicolor neutralization assay to simultaneously detect the neutralizing antibodies against different HPV types. FluoroSpot was used to interpret the fluorescent protein expression instead of flow cytometry. The results of FluoroSpot and flow cytometry showed good consistency, with R² > 0.98 for the log-transformed IC50 values. Regardless of the reporter color, the single-, dual-, and triple-color neutralization assays reported identical results for the same samples. In low-titer samples from naturally HPV-infected individuals, there was strong agreement between the single- and triple-color assays, with kappa scores of 0.92, 0.89, and 0.96 for HPV16, HPV18, and HPV58, respectively. Good reproducibility was observed for the triple-color assay, with coefficients of variation of 2.0%-41.5% within the assays and 8.3%-36.2% between the assays. Three triple-color systems, HPV16-18-58, HPV6-33-45, and HPV11-31-52, were developed that could evaluate the immunogenicity of a nonavalent vaccine in three rounds of the assay. With the advantages of an easy-to-use procedure and less sample consumption, the multiple-color assay is more suitable than classical assays for large sero-epidemiological studies and clinical trials and is more amenable to automation. PMID:27120611

  19. Immobilization of neutralized cladding-removal waste in a cement-based grout

    SciTech Connect

    Sams, T.L.; McDaniel, E.W.; Gilliam, T.M.

    1986-01-01

    Oak Ridge National Laboratory (ORNL) is providing technical support for the Transportable Grout Facility (TGF) currently being designed by Rockwell Hanford Operations in Richland, Washington. The grout formulas to be used in the TGF for disposal of low-level radioactive waste streams are being developed at ORNL. One such waste stream, neutralized cladding-removal waste (NCRW), has been identified for disposal, and a grout formula has subsequently been developed. The development of this formula required extensive testing to achieve adherence to several performance criteria. Both the grout formula and the results of this testing are presented. 9 refs., 3 figs., 5 tabs.

  20. New Neutral Interstellar Helium Flow Parameters Based on IBEX-Lo Observations

    NASA Astrophysics Data System (ADS)

    Bzowski, M.; Kubiak, M. A.; Moebius, E.; Bochsler, P. A.; Leonard, T.; Heirtzler, D.; Kucharek, H.; Crew, G. B.; Sokol, J. M.; Hlond, M.; Schwadron, N. A.; Fuselier, S. A.; McComas, D. J.

    2011-12-01

    Because of its high ionization potential and weak interaction with hydrogen, Neutral Interstellar Helium (NISHe) is almost unaffected at the heliospheric interface with the interstellar medium and freely enters the solar system. This second most abundant species provides some of the best information on the characteristics of the interstellar gas in the Local Interstellar Cloud (LIC). The Interstellar Boundary Explorer is the second mission to directly detect NISHe (after Ulysses) and the first to directly detect other interstellar neutrals. We present a comparison between recent IBEX NISHe observations and simulations carried out using a well-tested quantitative simulation code. This code includes motion of the spacecraft and the Earth relative to the incident NISHe in the inner heliosphere and accounts for both major and minor interactions between NISHe and its surrounding medium. The interactions include gravitational attraction by the Sun and losses by solar photoionization, electron impact ionization, and charge exchange with solar wind protons and alphas. Simulation and observation results compare well for times when measured fluxes are dominated by NISHe (and contributions from other species are small). Differences between simulations and observations indicate previously undetected secondary population of neutral helium, likely produced by interaction of helium with plasma in the outer heliosheath. Interstellar neutral parameters are statistically different from previous results: the newly-established flow direction is ecliptic longitude 79.2°, latitude -5.1°, velocity 22.8 km/s. These new results imply a markedly lower absolute velocity of the gas and thus significantly lower dynamic pressure on the boundaries of the heliosphere and different orientation of the Hydrogen Deflection Plane (the plane that contains the inflow vectors of hydrogen and helium in the inner heliosphere) compared to prior results from Ulysses. A different orientation of this plane

  1. Universal gates based on targeted phase shifts in a 3D neutral atom array

    NASA Astrophysics Data System (ADS)

    Kumar, Aishwarya; Wang, Yang; Wu, Tsung-Yao; Weiss, David

    2016-05-01

    We demonstrate a new approach to making targeted single qubit gates using Cesium atoms in a 5x5x5 3D neutral atom array. It combines targeted AC Zeeman phase shifts with global microwave pulses to produce arbitrary single qubit gates. Non-targeted atoms are left virtually untouched by the gates. We have addressed 48 sites, targeted individually, in a 40% full array. We have also performed Randomized Benchmarking to characterize the fidelity and crosstalk errors of this gate. These gates are highly insensitive to addressing beam imperfections and can be applied to other systems and geometries. Supported by NSF.

  2. The guitar chord-generating algorithm based on complex network

    NASA Astrophysics Data System (ADS)

    Ren, Tao; Wang, Yi-fan; Du, Dan; Liu, Miao-miao; Siddiqi, Awais

    2016-02-01

    This paper aims to generate chords for popular songs automatically based on complex network. Firstly, according to the characteristics of guitar tablature, six chord networks of popular songs by six pop singers are constructed and the properties of all networks are concluded. By analyzing the diverse chord networks, the accompaniment regulations and features are shown, with which the chords can be generated automatically. Secondly, in terms of the characteristics of popular songs, a two-tiered network containing a verse network and a chorus network is constructed. With this network, the verse and chorus can be composed respectively with the random walk algorithm. Thirdly, the musical motif is considered for generating chords, with which the bad chord progressions can be revised. This method can make the accompaniments sound more melodious. Finally, a popular song is chosen for generating chords and the new generated accompaniment sounds better than those done by the composers.

  3. Evidence That Calls-Based and Mobility Networks Are Isomorphic.

    PubMed

    Coscia, Michele; Hausmann, Ricardo

    2015-01-01

    Social relations involve both face-to-face interaction as well as telecommunications. We can observe the geography of phone calls and of the mobility of cell phones in space. These two phenomena can be described as networks of connections between different points in space. We use a dataset that includes billions of phone calls made in Colombia during a six-month period. We draw the two networks and find that the call-based network resembles a higher order aggregation of the mobility network and that both are isomorphic except for a higher spatial decay coefficient of the mobility network relative to the call-based network: when we discount distance effects on the call connections with the same decay observed for mobility connections, the two networks are virtually indistinguishable. PMID:26713730

  4. Evidence That Calls-Based and Mobility Networks Are Isomorphic

    PubMed Central

    Coscia, Michele; Hausmann, Ricardo

    2015-01-01

    Social relations involve both face-to-face interaction as well as telecommunications. We can observe the geography of phone calls and of the mobility of cell phones in space. These two phenomena can be described as networks of connections between different points in space. We use a dataset that includes billions of phone calls made in Colombia during a six-month period. We draw the two networks and find that the call-based network resembles a higher order aggregation of the mobility network and that both are isomorphic except for a higher spatial decay coefficient of the mobility network relative to the call-based network: when we discount distance effects on the call connections with the same decay observed for mobility connections, the two networks are virtually indistinguishable. PMID:26713730

  5. Research on Individualized Product Requirement Expression Based on Semantic Network

    NASA Astrophysics Data System (ADS)

    Yang, Qin; Pan, Xiuqin; Wei, Daozhu; Wu, Ke

    In order to establish an effective platform for individualized product development, the individualized product requirement expression forms were put forward. The diversity Semantic Network of product knowledge representation was researched based on the dualistic semantic network, and the product requirement framework model was established. Thereby the validity, reliability and consistency of the requirement expression process were ensured. Finally an example of customer requirement expression model about differential mechanism based on semantic network was described to satisfy with the individualized product design system.

  6. On Determining if Tree-based Networks Contain Fixed Trees.

    PubMed

    Anaya, Maria; Anipchenko-Ulaj, Olga; Ashfaq, Aisha; Chiu, Joyce; Kaiser, Mahedi; Ohsawa, Max Shoji; Owen, Megan; Pavlechko, Ella; St John, Katherine; Suleria, Shivam; Thompson, Keith; Yap, Corrine

    2016-05-01

    We address an open question of Francis and Steel about phylogenetic networks and trees. They give a polynomial time algorithm to decide if a phylogenetic network, N, is tree-based and pose the problem: given a fixed tree T and network N, is N based on T? We show that it is [Formula: see text]-hard to decide, by reduction from 3-Dimensional Matching (3DM) and further that the problem is fixed-parameter tractable. PMID:27125655

  7. Modeling activities on the negative-ion-based Neutral Beam Injectors of the Large Helical Device

    SciTech Connect

    Agostinetti, P.; Antoni, V.; Chitarin, G.; Pilan, N.; Serianni, G.; Veltri, P.; Cavenago, M.; Nakano, H.; Takeiri, Y.; Tsumori, K.

    2011-09-26

    At the National Institute for Fusion Science (NIFS) large-scaled negative ion sources have been widely used for the Neutral Beam Injectors (NBIs) mounted on the Large Helical Device (LHD), which is the world-largest superconducting helical system. These injectors have achieved outstanding performances in terms of beam energy, negative-ion current and optics, and represent a reference for the development of heating and current drive NBIs for ITER.In the framework of the support activities for the ITER NBIs, the PRIMA test facility, which includes a RF-drive ion source with 100 keV accelerator (SPIDER) and a complete 1 MeV Neutral Beam system (MITICA) is under construction at Consorzio RFX in Padova.An experimental validation of the codes has been undertaken in order to prove the accuracy of the simulations and the soundness of the SPIDER and MITICA design. To this purpose, the whole set of codes have been applied to the LHD NBIs in a joint activity between Consorzio RFX and NIFS, with the goal of comparing and benchmarking the codes with the experimental data. A description of these modeling activities and a discussion of the main results obtained are reported in this paper.

  8. Earthquake networks based on similar activity patterns.

    PubMed

    Tenenbaum, Joel N; Havlin, Shlomo; Stanley, H Eugene

    2012-10-01

    Earthquakes are a complex spatiotemporal phenomenon, the underlying mechanism for which is still not fully understood despite decades of research and analysis. We propose and develop a network approach to earthquake events. In this network, a node represents a spatial location while a link between two nodes represents similar activity patterns in the two different locations. The strength of a link is proportional to the strength of the cross correlation in activities of two nodes joined by the link. We apply our network approach to a Japanese earthquake catalog spanning the 14-year period 1985-1998. We find strong links representing large correlations between patterns in locations separated by more than 1000 kilometers, corroborating prior observations that earthquake interactions have no characteristic length scale. We find network characteristics not attributable to chance alone, including a large number of network links, high node assortativity, and strong stability over time. PMID:23214652

  9. Network Anomaly Detection Based on Wavelet Analysis

    NASA Astrophysics Data System (ADS)

    Lu, Wei; Ghorbani, Ali A.

    2008-12-01

    Signal processing techniques have been applied recently for analyzing and detecting network anomalies due to their potential to find novel or unknown intrusions. In this paper, we propose a new network signal modelling technique for detecting network anomalies, combining the wavelet approximation and system identification theory. In order to characterize network traffic behaviors, we present fifteen features and use them as the input signals in our system. We then evaluate our approach with the 1999 DARPA intrusion detection dataset and conduct a comprehensive analysis of the intrusions in the dataset. Evaluation results show that the approach achieves high-detection rates in terms of both attack instances and attack types. Furthermore, we conduct a full day's evaluation in a real large-scale WiFi ISP network where five attack types are successfully detected from over 30 millions flows.

  10. Pattern recognition tool based on complex network-based approach

    NASA Astrophysics Data System (ADS)

    Casanova, Dalcimar; Backes, André Ricardo; Martinez Bruno, Odemir

    2013-02-01

    This work proposed a generalization of the method proposed by the authors: 'A complex network-based approach for boundary shape analysis'. Instead of modelling a contour into a graph and use complex networks rules to characterize it, here, we generalize the technique. This way, the work proposes a mathematical tool for characterization signals, curves and set of points. To evaluate the pattern description power of the proposal, an experiment of plat identification based on leaf veins image are conducted. Leaf vein is a taxon characteristic used to plant identification proposes, and one of its characteristics is that these structures are complex, and difficult to be represented as a signal or curves and this way to be analyzed in a classical pattern recognition approach. Here, we model the veins as a set of points and model as graphs. As features, we use the degree and joint degree measurements in a dynamic evolution. The results demonstrates that the technique has a good power of discrimination and can be used for plant identification, as well as other complex pattern recognition tasks.

  11. Index : A Rule Based Expert System For Computer Network Maintenance

    NASA Astrophysics Data System (ADS)

    Chaganty, Srinivas; Pitchai, Anandhi; Morgan, Thomas W.

    1988-03-01

    Communications is an expert intensive discipline. The application of expert systems for maintenance of large and complex networks, mainly as an aid in trouble shooting, can simplify the task of network management. The important steps involved in troubleshooting are fault detection, fault reporting, fault interpretation and fault isolation. At present, Network Maintenance Facilities are capable of detecting and reporting the faults to network personnel. Fault interpretation refers to the next step in the process, which involves coming up with reasons for the failure. Fault interpretation can be characterized in two ways. First, it involves such a diversity of facts that it is difficult to predict. Secondly, it embodies a wealth of knowledge in the form of network management personnel. The application of expert systems in these interpretive tasks is an important step towards automation of network maintenance. In this paper, INDEX (Intelligent Network Diagnosis Expediter), a rule based production system for computer network alarm interpretation is described. It acts as an intelligent filter for people analyzing network alarms. INDEX analyzes the alarms in the network and identifies proper maintenance action to be taken.The important feature of this production system is that it is data driven. Working memory is the principal data repository of production systems and its contents represent the current state of the problem. Control is based upon which productions match the constantly changing working memory elements. Implementation of the prototype is in OPS83. Major issues in rule based system development such as rule base organization, implementation and efficiency are discussed.

  12. Improving Student Engagement Using Course-Based Social Networks

    ERIC Educational Resources Information Center

    Imlawi, Jehad Mohammad

    2013-01-01

    This study proposes an engagement model that supports use of course-based online social networks for engaging student, and hence, improving their educational outcomes. This research demonstrates that instructors who create course-based online social networks to communicate with students can increase the student engagement in these online social…

  13. Impact of short and long-range effects on the magnetic interactions in neutral organic radical-based materials.

    PubMed

    Domingo, Alex; Vérot, Martin; Mota, Fernando; de Graaf, Coen; Novoa, Juan J; Robert, Vincent

    2013-05-14

    The mutual influence of electronic structure and environment of the constituent units of neutral organic radical-based materials (radical dimers) is analysed by means of wave function calculations (Difference Dedicated Configuration Interaction, DDCI). Focus is put on the magnetic property modulations of two classes of neutral organic materials by inspecting both short- and long-range effects. The exchange coupling constant J for the high-temperature phase of the 1,3,5-trithia-2,4,6-triazapentalenyl (TTTA) material is calculated to be J= -95 cm(-1) at the DDCI level. The environmental electronic polarization is taken into account self-consistently using the individual polarizabilities of the atoms in a finite block of the crystal lattice (Discrete Reaction Field, DRF) and accounts for less than 5% of the calculated J value in TTTA. Furthermore, taking advantage of the chemical flexibility of the verdazyl radical family, the contribution of strong electron-withdrawing groups is analysed by extracting the J, U, t and K parameters from pairs of substituted verdazyl-based radicals. Our ab initio calculations of verdazyl radical pairs suggest that the addition of NO2 groups cause (i) the variations of the ferromagnetic and antiferromagnetic contributions to cancel out, leaving an almost constant exchange coupling constant, ca. J≈ 20 cm(-1), and that (ii) enhanced conduction properties can be anticipated. In contrast to inorganic analogues, one may conclude that the magnetic behaviour of neutral organic radical-based materials is mostly governed by the supramolecular arrangement, whereas environmental effects have a lesser impact. PMID:23552727

  14. Palladium on Nitrogen-Doped Mesoporous Carbon: A Bifunctional Catalyst for Formate-Based, Carbon-Neutral Hydrogen Storage.

    PubMed

    Wang, Fanan; Xu, Jinming; Shao, Xianzhao; Su, Xiong; Huang, Yanqiang; Zhang, Tao

    2016-02-01

    The lack of safe, efficient, and economical hydrogen storage technologies is a hindrance to the realization of the hydrogen economy. Reported herein is a reversible formate-based carbon-neutral hydrogen storage system that is established over a novel catalyst comprising palladium nanoparticles supported on nitrogen-doped mesoporous carbon. The support was fabricated by a hard template method and nitridated under a flow of ammonia. Detailed analyses demonstrate that this bicarbonate/formate redox equilibrium is promoted by the cooperative role of the doped nitrogen functionalities and the well-dispersed, electron-enriched palladium nanoparticles. PMID:26763714

  15. Networks based on collisions among mobile agents

    NASA Astrophysics Data System (ADS)

    González, Marta C.; Lind, Pedro G.; Herrmann, Hans J.

    2006-12-01

    We investigate in detail a recent model of colliding mobile agents [M.C. González, P.G. Lind, H.J. Herrmann, Phys. Rev. Lett. 96 (2006) 088702. cond-mat/0602091], used as an alternative approach for constructing evolving networks of interactions formed by collisions governed by suitable dynamical rules. The system of mobile agents evolves towards a quasi-stationary state which is, apart from small fluctuations, well characterized by the density of the system and the residence time of the agents. The residence time defines a collision rate, and by varying this collision rate, the system percolates at a critical value, with the emergence of a giant cluster whose critical exponents are the ones of two-dimensional percolation. Further, the degree and clustering coefficient distributions, and the average path length, show that the network associated with such a system presents non-trivial features which, depending on the collision rules, enables one not only to recover the main properties of standard networks, such as exponential, random and scale-free networks, but also to obtain other topological structures. To illustrate, we show a specific example where the obtained structure has topological features which characterize the structure and evolution of social networks accurately in different contexts, ranging from networks of acquaintances to networks of sexual contacts.

  16. Neural Network Based Intelligent Sootblowing System

    SciTech Connect

    Mark Rhode

    2005-04-01

    , particulate matter is also a by-product of coal combustion. Modern day utility boilers are usually fitted with electrostatic precipitators to aid in the collection of particulate matter. Although extremely efficient, these devices are sensitive to rapid changes in inlet mass concentration as well as total mass loading. Traditionally, utility boilers are equipped with devices known as sootblowers, which use, steam, water or air to dislodge and clean the surfaces within the boiler and are operated based upon established rule or operator's judgment. Poor sootblowing regimes can influence particulate mass loading to the electrostatic precipitators. The project applied a neural network intelligent sootblowing system in conjunction with state-of-the-art controls and instruments to optimize the operation of a utility boiler and systematically control boiler slagging/fouling. This optimization process targeted reduction of NOx of 30%, improved efficiency of 2% and a reduction in opacity of 5%. The neural network system proved to be a non-invasive system which can readily be adapted to virtually any utility boiler. Specific conclusions from this neural network application are listed below. These conclusions should be used in conjunction with the specific details provided in the technical discussions of this report to develop a thorough understanding of the process.

  17. Image-Based Structural Modeling of the Cardiac Purkinje Network

    PubMed Central

    Liu, Benjamin R.; Cherry, Elizabeth M.

    2015-01-01

    The Purkinje network is a specialized conduction system within the heart that ensures the proper activation of the ventricles to produce effective contraction. Its role during ventricular arrhythmias is less clear, but some experimental studies have suggested that the Purkinje network may significantly affect the genesis and maintenance of ventricular arrhythmias. Despite its importance, few structural models of the Purkinje network have been developed, primarily because current physical limitations prevent examination of the intact Purkinje network. In previous modeling efforts Purkinje-like structures have been developed through either automated or hand-drawn procedures, but these networks have been created according to general principles rather than based on real networks. To allow for greater realism in Purkinje structural models, we present a method for creating three-dimensional Purkinje networks based directly on imaging data. Our approach uses Purkinje network structures extracted from photographs of dissected ventricles and projects these flat networks onto realistic endocardial surfaces. Using this method, we create models for the combined ventricle-Purkinje system that can fully activate the ventricles through a stimulus delivered to the Purkinje network and can produce simulated activation sequences that match experimental observations. The combined models have the potential to help elucidate Purkinje network contributions during ventricular arrhythmias. PMID:26583120

  18. Resiliency of EEG-Based Brain Functional Networks

    PubMed Central

    Jalili, Mahdi

    2015-01-01

    Applying tools available in network science and graph theory to study brain networks has opened a new era in understanding brain mechanisms. Brain functional networks extracted from EEG time series have been frequently studied in health and diseases. In this manuscript, we studied failure resiliency of EEG-based brain functional networks. The network structures were extracted by analysing EEG time series obtained from 30 healthy subjects in resting state eyes-closed conditions. As the network structure was extracted, we measured a number of metrics related to their resiliency. In general, the brain networks showed worse resilient behaviour as compared to corresponding random networks with the same degree sequences. Brain networks had higher vulnerability than the random ones (P < 0.05), indicating that their global efficiency (i.e., communicability between the regions) is more affected by removing the important nodes. Furthermore, the breakdown happened as a result of cascaded failures in brain networks was severer (i.e., less nodes survived) as compared to randomized versions (P < 0.05). These results suggest that real EEG-based networks have not been evolved to possess optimal resiliency against failures. PMID:26295341

  19. Best practice recommendations for the transfer of cell-based assays for the measurement of neutralizing anti-drug antibodies.

    PubMed

    Belouski, Shelley S; Born, Danika; Jacques, Susan; Harder, Brandon; Reynhardt, Kai; Kaliyaperumal, Arunan; Gupta, Shalini

    2016-09-01

    We recommend the application of a strategically designed step-wise approach to transfer cell-based assays that includes assessing analytical performance (through a fit for purpose validation and/or design of experiment robustness characterization), clinical performance (i.e., concordance) and performance or proficiency testing for long-term method monitoring. Here we focus on the application of this strategy to cell-based assays for the measurement of neutralizing anti-drug antibodies. This application is unique in that it requires a custom cell-based assay to be used over a long period of time (potentially phase 1a through the life of a marketed product) with the confidence of consistent method performance and result reporting. But, the process is adaptable to a variety of assay types and applications. We present lessons learned from two cell-based assay transfers that met relevant challenges while implementing alternative permutations of the recommended method transfer process. PMID:27523191

  20. Space-Based Voice over IP Networks

    NASA Technical Reports Server (NTRS)

    Nguyen, Sam P.; Okino, Clayton; Walsh, William; Clare, Loren

    2007-01-01

    In human space exploration missions (e.g. a return to the Moon and for future missions to Mars), there will be a need to provide voice communications services. In this work we focus on the performance of Voice over IP (VoIP) techniques applied to space networks, where long range latencies, simplex links, and significant bit error rates occur. Link layer and network layer overhead issues are examined. Finally, we provide some discussion on issues related to voice conferencing in the space network environment.

  1. Structure-based ligand discovery for the Large-neutral Amino Acid Transporter 1, LAT-1.

    PubMed

    Geier, Ethan G; Schlessinger, Avner; Fan, Hao; Gable, Jonathan E; Irwin, John J; Sali, Andrej; Giacomini, Kathleen M

    2013-04-01

    The Large-neutral Amino Acid Transporter 1 (LAT-1)--a sodium-independent exchanger of amino acids, thyroid hormones, and prescription drugs--is highly expressed in the blood-brain barrier and various types of cancer. LAT-1 plays an important role in cancer development as well as in mediating drug and nutrient delivery across the blood-brain barrier, making it a key drug target. Here, we identify four LAT-1 ligands, including one chemically novel substrate, by comparative modeling, virtual screening, and experimental validation. These results may rationalize the enhanced brain permeability of two drugs, including the anticancer agent acivicin. Finally, two of our hits inhibited proliferation of a cancer cell line by distinct mechanisms, providing useful chemical tools to characterize the role of LAT-1 in cancer metabolism. PMID:23509259

  2. Color-neutral switchable mirrors based on magnesium-titanium thin films

    NASA Astrophysics Data System (ADS)

    Bao, S.; Tajima, K.; Yamada, Y.; Okada, M.; Yoshimura, K.

    2007-06-01

    In an investigation of smart-window applications of switchable mirror thin films, Pd-capped magnesium-titanium thin films were prepared by dc magnetron sputtering. Their optical properties, switching durability and crystalline structures have been investigated. We show that Pd/Mg-Ti thin films with specific thicknesses are completely color-neutral in the transparent state and their optical switching properties are suitable for building and automobile window glass applications. The ternary hydrides of Mg(1-x)Tix thin films with Pd overlayers are identified by in situ X-ray diffraction measurements during a hydrogen gas loading of 4%. Pd/Mg(1-x)Tix thin film switchable mirrors show fast hydriding and dehydriding kinetics as compared to a Pd-capped pure Mg thin film due to the catalytic role of doped metallic Ti.

  3. Structure-based ligand discovery for the Large-neutral Amino Acid Transporter 1, LAT-1

    PubMed Central

    Geier, Ethan G.; Schlessinger, Avner; Fan, Hao; Gable, Jonathan E.; Irwin, John J.; Sali, Andrej; Giacomini, Kathleen M.

    2013-01-01

    The Large-neutral Amino Acid Transporter 1 (LAT-1)—a sodium-independent exchanger of amino acids, thyroid hormones, and prescription drugs—is highly expressed in the blood–brain barrier and various types of cancer. LAT-1 plays an important role in cancer development as well as in mediating drug and nutrient delivery across the blood–brain barrier, making it a key drug target. Here, we identify four LAT-1 ligands, including one chemically novel substrate, by comparative modeling, virtual screening, and experimental validation. These results may rationalize the enhanced brain permeability of two drugs, including the anticancer agent acivicin. Finally, two of our hits inhibited proliferation of a cancer cell line by distinct mechanisms, providing useful chemical tools to characterize the role of LAT-1 in cancer metabolism. PMID:23509259

  4. Zone-Based Routing Protocol for Wireless Sensor Networks

    PubMed Central

    Venkateswarlu Kumaramangalam, Muni; Adiyapatham, Kandasamy; Kandasamy, Chandrasekaran

    2014-01-01

    Extensive research happening across the globe witnessed the importance of Wireless Sensor Network in the present day application world. In the recent past, various routing algorithms have been proposed to elevate WSN network lifetime. Clustering mechanism is highly successful in conserving energy resources for network activities and has become promising field for researches. However, the problem of unbalanced energy consumption is still open because the cluster head activities are tightly coupled with role and location of a particular node in the network. Several unequal clustering algorithms are proposed to solve this wireless sensor network multihop hot spot problem. Current unequal clustering mechanisms consider only intra- and intercluster communication cost. Proper organization of wireless sensor network into clusters enables efficient utilization of limited resources and enhances lifetime of deployed sensor nodes. This paper considers a novel network organization scheme, energy-efficient edge-based network partitioning scheme, to organize sensor nodes into clusters of equal size. Also, it proposes a cluster-based routing algorithm, called zone-based routing protocol (ZBRP), for elevating sensor network lifetime. Experimental results show that ZBRP out-performs interims of network lifetime and energy conservation with its uniform energy consumption among the cluster heads.

  5. Synthetic thermosphere winds based on CHAMP neutral and plasma density measurements

    NASA Astrophysics Data System (ADS)

    Gasperini, F.; Forbes, J. M.; Doornbos, E. N.; Bruinsma, S. L.

    2016-04-01

    Meridional winds in the thermosphere are key to understanding latitudinal coupling and thermosphere-ionosphere coupling, and yet global measurements of this wind component are scarce. In this work, neutral and electron densities measured by the Challenging Minisatellite Payload (CHAMP) satellite at solar low and geomagnetically quiet conditions are converted to pressure gradient and ion drag forces, which are then used to solve the horizontal momentum equation to estimate low latitude to midlatitude zonal and meridional "synthetic" winds. We validate the method by showing that neutral and electron densities output from National Center for Atmospheric Research (NCAR) Thermosphere Ionosphere Mesosphere Electrodynamics-General Circulation Model (TIME-GCM) can be used to derive solutions to the momentum equations that replicate reasonably well (over 85% of the variance) the winds self-consistently calculated within the TIME-GCM. CHAMP cross-track winds are found to share over 65% of the variance with the synthetic zonal winds, providing further reassurance that this wind product should provide credible results. Comparisons with the Horizontal Wind Model 14 (HWM14) show that the empirical model largely underestimates wind speeds and does not reproduce much of the observed variability. Additionally, in this work we reveal the longitude, latitude, local time, and seasonal variability in the winds; show evidence of ionosphere-thermosphere (IT) coupling, with enhanced postsunset eastward winds due to depleted ion drag; demonstrate superrotation speeds of ˜27 m/s at the equator; discuss vertical wave coupling due the diurnal eastward propagating tide with zonal wave number 3 and the semidiurnal eastward propagating tide with zonal wave number 2.

  6. Research of home networking system based on XML/BACnet

    NASA Astrophysics Data System (ADS)

    Wang, Zhongming

    2008-11-01

    To standardize home networking information and simplify its management, this paper form a universal information module of various devices in home networking by adopting XML technology and BACnet protocol(XML/BACnet). Then, a software architecture of home networking based on this module is designed, having the function like auto management and maintenance, safety, real-time and remote controlling. Consequently, a home networking system based on this architecture is completed. Tested and evaluated, this system is one easy-using, easy-realizing, nice real-time system with strong heterogeneity and stable safety system.

  7. Development of a neutralization assay for influenza virus using an endpoint assessment based on quantitative reverse-transcription PCR.

    PubMed

    Teferedegne, Belete; Lewis, Andrew M; Peden, Keith; Murata, Haruhiko

    2013-01-01

    A microneutralization assay using an ELISA-based endpoint assessment (ELISA-MN) is widely used to measure the serological response to influenza virus infection and vaccination. We have developed an alternative microneutralization assay for influenza virus using a quantitative reverse transcription PCR-based endpoint assessment (qPCR-MN) in order to improve upon technical limitations associated with ELISA-MN. For qPCR-MN, infected MDCK-London cells in 96-well cell-culture plates are processed with minimal steps such that resulting samples are amenable to high-throughput analysis by downstream one-step quantitative reverse transcription PCR (qRT-PCR; SYBR Green chemistry with primers targeting a conserved region of the M1 gene of influenza A viruses). The growth curves of three recent vaccine strains demonstrated that the qRT-PCR signal detected at 6 hours post-infection reflected an amplification of at least 100-fold over input. Using ferret antisera, we have established the feasibility of measuring virus neutralization at 6 hours post-infection, a duration likely confined to a single virus-replication cycle. The neutralization titer for qPCR-MN was defined as the highest reciprocal serum dilution necessary to achieve a 90% inhibition of the qRT-PCR signal; this endpoint was found to be in agreement with ELISA-MN using the same critical reagents in each assay. qPCR-MN was robust with respect to assay duration (6 hours vs. 12 hours). In addition, qPCR-MN appeared to be compliant with the Percentage Law (i.e., virus neutralization results appear to be consistent over an input virus dose ranging from 500 to 12,000 TCID(50)). Compared with ELISA-MN, qPCR-MN might have inherent properties conducive to reducing intra- and inter-laboratory variability while affording suitability for automation and high-throughput uses. Finally, our qRT-PCR-based approach may be broadly applicable to the development of neutralization assays for a wide variety of viruses. PMID:23437084

  8. Cointegration-based financial networks study in Chinese stock market

    NASA Astrophysics Data System (ADS)

    Tu, Chengyi

    2014-05-01

    We propose a method based on cointegration instead of correlation to construct financial complex network in Chinese stock market. The network is obtained starting from the matrix of p-value calculated by Engle-Granger cointegration test between all pairs of stocks. Then some tools for filtering information in complex network are implemented to prune the complete graph described by the above matrix, such as setting a level of statistical significance as a threshold and Planar Maximally Filtered Graph. We also calculate Partial Correlation Planar Graph of these stocks to compare the above networks. Last, we analyze these directed, weighted and non-symmetric networks by using standard methods of network analysis, including degree centrality, PageRank, HITS, local clustering coefficient, K-shell and strongly and weakly connected components. The results shed a new light on the underlying mechanisms and driving forces in a financial market and deepen our understanding of financial complex network.

  9. Constructing Phylogenetic Networks Based on the Isomorphism of Datasets

    PubMed Central

    Zhang, Zhibin; Li, Yanjuan

    2016-01-01

    Constructing rooted phylogenetic networks from rooted phylogenetic trees has become an important problem in molecular evolution. So far, many methods have been presented in this area, in which most efficient methods are based on the incompatible graph, such as the CASS, the LNETWORK, and the BIMLR. This paper will research the commonness of the methods based on the incompatible graph, the relationship between incompatible graph and the phylogenetic network, and the topologies of incompatible graphs. We can find out all the simplest datasets for a topology G and construct a network for every dataset. For any one dataset 𝒞, we can compute a network from the network representing the simplest dataset which is isomorphic to 𝒞. This process will save more time for the algorithms when constructing networks. PMID:27547759

  10. Finite-sample based learning algorithms for feedforward networks

    SciTech Connect

    Rao, N.S.V.; Protopopescu, V.; Mann, R.C.; Oblow, E.M.; Iyengar, S.S.

    1995-04-01

    We discuss two classes of convergent algorithms for learning continuous functions (and also regression functions) that are represented by FeedForward Networks (FFN). The first class of algorithms, applicable to networks with unknown weights located only in the output layer, is obtained by utilizing the potential function methods of Aizerman et al. The second class, applicable to general feedforward networks, is obtained by utilizing the classical Robbins-Monro style stochastic approximation methods. Conditions relating the sample sizes to the error bounds are derived for both classes of algorithms using martingale-type inequalities. For concreteness, the discussion is presented in terms of neural networks, but the results are applicable to general feedforward networks, in particular to wavelet networks. The algorithms can also be directly applied to concept learning problems. A main distinguishing feature of the this work is that the sample sizes are based on explicit algorithms rather than information-based methods.

  11. Constructing Phylogenetic Networks Based on the Isomorphism of Datasets.

    PubMed

    Wang, Juan; Zhang, Zhibin; Li, Yanjuan

    2016-01-01

    Constructing rooted phylogenetic networks from rooted phylogenetic trees has become an important problem in molecular evolution. So far, many methods have been presented in this area, in which most efficient methods are based on the incompatible graph, such as the CASS, the LNETWORK, and the BIMLR. This paper will research the commonness of the methods based on the incompatible graph, the relationship between incompatible graph and the phylogenetic network, and the topologies of incompatible graphs. We can find out all the simplest datasets for a topology G and construct a network for every dataset. For any one dataset , we can compute a network from the network representing the simplest dataset which is isomorphic to . This process will save more time for the algorithms when constructing networks. PMID:27547759

  12. Blur identification by multilayer neural network based on multivalued neurons.

    PubMed

    Aizenberg, Igor; Paliy, Dmitriy V; Zurada, Jacek M; Astola, Jaakko T

    2008-05-01

    A multilayer neural network based on multivalued neurons (MLMVN) is a neural network with a traditional feedforward architecture. At the same time, this network has a number of specific different features. Its backpropagation learning algorithm is derivative-free. The functionality of MLMVN is superior to that of the traditional feedforward neural networks and of a variety kernel-based networks. Its higher flexibility and faster adaptation to the target mapping enables to model complex problems using simpler networks. In this paper, the MLMVN is used to identify both type and parameters of the point spread function, whose precise identification is of crucial importance for the image deblurring. The simulation results show the high efficiency of the proposed approach. It is confirmed that the MLMVN is a powerful tool for solving classification problems, especially multiclass ones. PMID:18467216

  13. Development and validation of cell-based assays for the detection of neutralizing antibodies to drug products: a practical approach.

    PubMed

    Jolicoeur, Pierre; Tacey, Richard L

    2012-12-01

    Neutralizing antibodies (NAbs) that bind to drug products and may diminish or eliminate the associated biological activity are an unintended and undesirable outcome of some drug products. Standard immunoassays can detect drug-specific antibodies but cannot distinguish NAbs, so cell-based assays are often preferred because they closely mimic the mechanism by which NAbs and drug products interact in vivo. Each cell-based NAb assay is unique and based on several factors, such as the drug product, study population and phase of development (preclinical or clinical). The type of NAb assay (direct or indirect) depends on the drug's mechanism of action. Key steps in assay development are: selecting a suitable cell line, choosing the proper cellular response (end point method), selection of proper controls and optimization of assay parameters. Once developed, the assay must be rigorously tested (validated) to ensure that it meets several important criteria and is fit for its intended purpose. PMID:23244285

  14. Sentiment Diffusion of Public Opinions about Hot Events: Based on Complex Network.

    PubMed

    Hao, Xiaoqing; An, Haizhong; Zhang, Lijia; Li, Huajiao; Wei, Guannan

    2015-01-01

    To study the sentiment diffusion of online public opinions about hot events, we collected people's posts through web data mining techniques. We calculated the sentiment value of each post based on a sentiment dictionary. Next, we divided those posts into five different orientations of sentiments: strongly positive (P), weakly positive (p), neutral (o), weakly negative (n), and strongly negative (N). These sentiments are combined into modes through coarse graining. We constructed sentiment mode complex network of online public opinions (SMCOP) with modes as nodes and the conversion relation in chronological order between different types of modes as edges. We calculated the strength, k-plex clique, clustering coefficient and betweenness centrality of the SMCOP. The results show that the strength distribution obeys power law. Most posts' sentiments are weakly positive and neutral, whereas few are strongly negative. There are weakly positive subgroups and neutral subgroups with ppppp and ooooo as the core mode, respectively. Few modes have larger betweenness centrality values and most modes convert to each other with these higher betweenness centrality modes as mediums. Therefore, the relevant person or institutes can take measures to lead people's sentiments regarding online hot events according to the sentiment diffusion mechanism. PMID:26462230

  15. Sentiment Diffusion of Public Opinions about Hot Events: Based on Complex Network

    PubMed Central

    Hao, Xiaoqing; An, Haizhong; Zhang, Lijia; Li, Huajiao; Wei, Guannan

    2015-01-01

    To study the sentiment diffusion of online public opinions about hot events, we collected people’s posts through web data mining techniques. We calculated the sentiment value of each post based on a sentiment dictionary. Next, we divided those posts into five different orientations of sentiments: strongly positive (P), weakly positive (p), neutral (o), weakly negative (n), and strongly negative (N). These sentiments are combined into modes through coarse graining. We constructed sentiment mode complex network of online public opinions (SMCOP) with modes as nodes and the conversion relation in chronological order between different types of modes as edges. We calculated the strength, k-plex clique, clustering coefficient and betweenness centrality of the SMCOP. The results show that the strength distribution obeys power law. Most posts’ sentiments are weakly positive and neutral, whereas few are strongly negative. There are weakly positive subgroups and neutral subgroups with ppppp and ooooo as the core mode, respectively. Few modes have larger betweenness centrality values and most modes convert to each other with these higher betweenness centrality modes as mediums. Therefore, the relevant person or institutes can take measures to lead people’s sentiments regarding online hot events according to the sentiment diffusion mechanism. PMID:26462230

  16. Protecting infrastructure networks from cost-based attacks

    NASA Astrophysics Data System (ADS)

    Wang, Xingang; Guan, Shuguang; Heng Lai, Choy

    2009-03-01

    It is well known that heterogeneous networks are vulnerable to the intentional removal of a small fraction of highly connected or loaded nodes, implying that to protect the network effectively, the important nodes should be allocated more defense resource than the others. However, if too much resource is allocated to the few important nodes, the numerous less-important nodes will be less protected, which if attacked together can still lead to devastating damage. A natural question is therefore how to efficiently distribute the limited defense resource among the network nodes such that the network damage is minimized against any attack strategy. In this paper, taking into account the factor of attack cost, the problem of network security is reconsidered in terms of efficient network defense against cost-based attacks. The results show that, for a general complex network, there exists an optimal distribution of the defense resource with which the network is best protected from cost-based attacks. Furthermore, it is found that the configuration of the optimal defense is dependent on the network parameters. Specifically, networks of larger size, sparser connection and more heterogeneous structure will more likely benefit from the defense optimization.

  17. Neural network based speech synthesizer: A preliminary report

    NASA Technical Reports Server (NTRS)

    Villarreal, James A.; Mcintire, Gary

    1987-01-01

    A neural net based speech synthesis project is discussed. The novelty is that the reproduced speech was extracted from actual voice recordings. In essence, the neural network learns the timing, pitch fluctuations, connectivity between individual sounds, and speaking habits unique to that individual person. The parallel distributed processing network used for this project is the generalized backward propagation network which has been modified to also learn sequences of actions or states given in a particular plan.

  18. Improved community model for social networks based on social mobility

    NASA Astrophysics Data System (ADS)

    Lu, Zhe-Ming; Wu, Zhen; Luo, Hao; Wang, Hao-Xian

    2015-07-01

    This paper proposes an improved community model for social networks based on social mobility. The relationship between the group distribution and the community size is investigated in terms of communication rate and turnover rate. The degree distributions, clustering coefficients, average distances and diameters of networks are analyzed. Experimental results demonstrate that the proposed model possesses the small-world property and can reproduce social networks effectively and efficiently.

  19. Neutral particle beam intensity controller

    DOEpatents

    Dagenhart, W.K.

    1984-05-29

    The neutral beam intensity controller is based on selected magnetic defocusing of the ion beam prior to neutralization. The defocused portion of the beam is dumped onto a beam dump disposed perpendicular to the beam axis. Selective defocusing is accomplished by means of a magnetic field generator disposed about the neutralizer so that the field is transverse to the beam axis. The magnetic field intensity is varied to provide the selected partial beam defocusing of the ions prior to neutralization. The desired focused neutral beam portion passes along the beam path through a defining aperture in the beam dump, thereby controlling the desired fraction of neutral particles transmitted to a utilization device without altering the kinetic energy level of the desired neutral particle fraction. By proper selection of the magnetic field intensity, virtually zero through 100% intensity control of the neutral beam is achieved.

  20. A novel interacting multiple model based network intrusion detection scheme

    NASA Astrophysics Data System (ADS)

    Xin, Ruichi; Venkatasubramanian, Vijay; Leung, Henry

    2006-04-01

    In today's information age, information and network security are of primary importance to any organization. Network intrusion is a serious threat to security of computers and data networks. In internet protocol (IP) based network, intrusions originate in different kinds of packets/messages contained in the open system interconnection (OSI) layer 3 or higher layers. Network intrusion detection and prevention systems observe the layer 3 packets (or layer 4 to 7 messages) to screen for intrusions and security threats. Signature based methods use a pre-existing database that document intrusion patterns as perceived in the layer 3 to 7 protocol traffics and match the incoming traffic for potential intrusion attacks. Alternately, network traffic data can be modeled and any huge anomaly from the established traffic pattern can be detected as network intrusion. The latter method, also known as anomaly based detection is gaining popularity for its versatility in learning new patterns and discovering new attacks. It is apparent that for a reliable performance, an accurate model of the network data needs to be established. In this paper, we illustrate using collected data that network traffic is seldom stationary. We propose the use of multiple models to accurately represent the traffic data. The improvement in reliability of the proposed model is verified by measuring the detection and false alarm rates on several datasets.

  1. FPGA-based artificial neural network using CORDIC modules

    NASA Astrophysics Data System (ADS)

    Liddicoat, Albert A.; Slivovsky, Lynne A.; McLenegan, Tim; Heyer, Don

    2006-08-01

    Artificial neural networks have been used in applications that require complex procedural algorithms and in systems which lack an analytical mathematic model. By designing a large network of computing nodes based on the artificial neuron model, new solutions can be developed for computational problems in fields such as image processing and speech recognition. Neural networks are inherently parallel since each neuron, or node, acts as an autonomous computational element. Artificial neural networks use a mathematical model for each node that processes information from other nodes in the same region. The information processing entails computing a weighted average computation followed by a nonlinear mathematical transformation. Some typical artificial neural network applications use the exponential function or trigonometric functions for the nonlinear transformation. Various simple artificial neural networks have been implemented using a processor to compute the output for each node sequentially. This approach uses sequential processing and does not take advantage of the parallelism of a complex artificial neural network. In this work a hardware-based approach is investigated for artificial neural network applications. A Field Programmable Gate Arrays (FPGAs) is used to implement an artificial neuron using hardware multipliers, adders and CORDIC functional units. In order to create a large scale artificial neural network, area efficient hardware units such as CORDIC units are needed. High performance and low cost bit serial CORDIC implementations are presented. Finally, the FPGA resources and the performance of a hardware-based artificial neuron are presented.

  2. Fault location of underground distribution network based on RBF network optimized by improved PSO algorithm

    NASA Astrophysics Data System (ADS)

    Tian, Shu; Zhao, Min

    2013-03-01

    To solve the difficult problem that exists in the location of single-phase ground fault for coal mine underground distribution network, a fault location method using RBF network optimized by improved PSO algorithm based on the mapping relationship between wavelet packet transform modulus maxima of specific frequency bands transient state zero sequence current in the fault line and fault point position is presented. The simulation analysis results in the cases of different transition resistances and fault distances show that the RBF network optimized by improved PSO algorithm can obtain accurate and reliable fault location results, and the fault location perfor- mance is better than traditional RBF network.

  3. A novel mechanism for antibody-based anthrax toxin neutralization: inhibition of prepore-to-pore conversion.

    PubMed

    Mechaly, Adva; Levy, Haim; Epstein, Eyal; Rosenfeld, Ronit; Marcus, Hadar; Ben-Arie, Einat; Shafferman, Avigdor; Ordentlich, Arie; Mazor, Ohad

    2012-09-21

    Protective antigen (PA), a key component of anthrax toxin, mediates the entry of lethal factor (LF) or edema factor (EF) through a membranal pore into target cells. We have previously reported the isolation and chimerization of cAb29, an anti-PA monoclonal antibody that effectively neutralizes anthrax toxin in an unknown mechanism. The aim of this study was to elucidate the neutralizing mechanism of this antibody in vitro and to test its ability to confer post-exposure protection against anthrax in vivo. By systematic evaluation of the steps taking place during the PA-based intoxication process, we found that cAb29 did not interfere with the initial steps of intoxication, namely its ability to bind to the anthrax receptor, the consecutive proteolytic cleavage to PA(63), oligomerization, prepore formation, or LF binding. However, the binding of cAb29 to the prepore prevented its pH-triggered transition to the transmembranal pore, thus preventing the last step of intoxication, i.e. the translocation of LF/EF into the cell. Epitope mapping, using a phage display peptide library, revealed that cAb29 binds the 2α(1) loop in domain 2 of PA, a loop that undergoes major conformational changes during pore formation. In vivo, we found that 100% of anthrax-infected rabbits survived when treated with cAb29 12 h after exposure. In conclusion, these experiments demonstrate that cAb29 exerts its potent neutralizing activity in a unique manner by blocking the prepore-to-pore conversion process. PMID:22869370

  4. The Net Neutrality Debate: The Basics

    ERIC Educational Resources Information Center

    Greenfield, Rich

    2006-01-01

    Rich Greenfield examines the basics of today's net neutrality debate that is likely to be an ongoing issue for society. Greenfield states the problems inherent in the definition of "net neutrality" used by Common Cause: "Network neutrality is the principle that Internet users should be able to access any web content they choose and use any…

  5. Segmenting the human genome based on states of neutral genetic divergence.

    PubMed

    Kuruppumullage Don, Prabhani; Ananda, Guruprasad; Chiaromonte, Francesca; Makova, Kateryna D

    2013-09-01

    Many studies have demonstrated that divergence levels generated by different mutation types vary and covary across the human genome. To improve our still-incomplete understanding of the mechanistic basis of this phenomenon, we analyze several mutation types simultaneously, anchoring their variation to specific regions of the genome. Using hidden Markov models on insertion, deletion, nucleotide substitution, and microsatellite divergence estimates inferred from human-orangutan alignments of neutrally evolving genomic sequences, we segment the human genome into regions corresponding to different divergence states--each uniquely characterized by specific combinations of divergence levels. We then parsed the mutagenic contributions of various biochemical processes associating divergence states with a broad range of genomic landscape features. We find that high divergence states inhabit guanine- and cytosine (GC)-rich, highly recombining subtelomeric regions; low divergence states cover inner parts of autosomes; chromosome X forms its own state with lowest divergence; and a state of elevated microsatellite mutability is interspersed across the genome. These general trends are mirrored in human diversity data from the 1000 Genomes Project, and departures from them highlight the evolutionary history of primate chromosomes. We also find that genes and noncoding functional marks [annotations from the Encyclopedia of DNA Elements (ENCODE)] are concentrated in high divergence states. Our results provide a powerful tool for biomedical data analysis: segmentations can be used to screen personal genome variants--including those associated with cancer and other diseases--and to improve computational predictions of noncoding functional elements. PMID:23959903

  6. Network-based prediction of protein function

    PubMed Central

    Sharan, Roded; Ulitsky, Igor; Shamir, Ron

    2007-01-01

    Functional annotation of proteins is a fundamental problem in the post-genomic era. The recent availability of protein interaction networks for many model species has spurred on the development of computational methods for interpreting such data in order to elucidate protein function. In this review, we describe the current computational approaches for the task, including direct methods, which propagate functional information through the network, and module-assisted methods, which infer functional modules within the network and use those for the annotation task. Although a broad variety of interesting approaches has been developed, further progress in the field will depend on systematic evaluation of the methods and their dissemination in the biological community. PMID:17353930

  7. Self-organized topology of recurrence-based complex networks

    SciTech Connect

    Yang, Hui Liu, Gang

    2013-12-15

    With the rapid technological advancement, network is almost everywhere in our daily life. Network theory leads to a new way to investigate the dynamics of complex systems. As a result, many methods are proposed to construct a network from nonlinear time series, including the partition of state space, visibility graph, nearest neighbors, and recurrence approaches. However, most previous works focus on deriving the adjacency matrix to represent the complex network and extract new network-theoretic measures. Although the adjacency matrix provides connectivity information of nodes and edges, the network geometry can take variable forms. The research objective of this article is to develop a self-organizing approach to derive the steady geometric structure of a network from the adjacency matrix. We simulate the recurrence network as a physical system by treating the edges as springs and the nodes as electrically charged particles. Then, force-directed algorithms are developed to automatically organize the network geometry by minimizing the system energy. Further, a set of experiments were designed to investigate important factors (i.e., dynamical systems, network construction methods, force-model parameter, nonhomogeneous distribution) affecting this self-organizing process. Interestingly, experimental results show that the self-organized geometry recovers the attractor of a dynamical system that produced the adjacency matrix. This research addresses a question, i.e., “what is the self-organizing geometry of a recurrence network?” and provides a new way to reproduce the attractor or time series from the recurrence plot. As a result, novel network-theoretic measures (e.g., average path length and proximity ratio) can be achieved based on actual node-to-node distances in the self-organized network topology. The paper brings the physical models into the recurrence analysis and discloses the spatial geometry of recurrence networks.

  8. Self-organized topology of recurrence-based complex networks

    NASA Astrophysics Data System (ADS)

    Yang, Hui; Liu, Gang

    2013-12-01

    With the rapid technological advancement, network is almost everywhere in our daily life. Network theory leads to a new way to investigate the dynamics of complex systems. As a result, many methods are proposed to construct a network from nonlinear time series, including the partition of state space, visibility graph, nearest neighbors, and recurrence approaches. However, most previous works focus on deriving the adjacency matrix to represent the complex network and extract new network-theoretic measures. Although the adjacency matrix provides connectivity information of nodes and edges, the network geometry can take variable forms. The research objective of this article is to develop a self-organizing approach to derive the steady geometric structure of a network from the adjacency matrix. We simulate the recurrence network as a physical system by treating the edges as springs and the nodes as electrically charged particles. Then, force-directed algorithms are developed to automatically organize the network geometry by minimizing the system energy. Further, a set of experiments were designed to investigate important factors (i.e., dynamical systems, network construction methods, force-model parameter, nonhomogeneous distribution) affecting this self-organizing process. Interestingly, experimental results show that the self-organized geometry recovers the attractor of a dynamical system that produced the adjacency matrix. This research addresses a question, i.e., "what is the self-organizing geometry of a recurrence network?" and provides a new way to reproduce the attractor or time series from the recurrence plot. As a result, novel network-theoretic measures (e.g., average path length and proximity ratio) can be achieved based on actual node-to-node distances in the self-organized network topology. The paper brings the physical models into the recurrence analysis and discloses the spatial geometry of recurrence networks.

  9. Connected Dominating Set Based Topology Control in Wireless Sensor Networks

    ERIC Educational Resources Information Center

    He, Jing

    2012-01-01

    Wireless Sensor Networks (WSNs) are now widely used for monitoring and controlling of systems where human intervention is not desirable or possible. Connected Dominating Sets (CDSs) based topology control in WSNs is one kind of hierarchical method to ensure sufficient coverage while reducing redundant connections in a relatively crowded network.…

  10. Place Based Assistance Tools: Networking and Resident Surveys.

    ERIC Educational Resources Information Center

    Department of Housing and Urban Development, Washington, DC.

    "Place-based assistance" is not a new concept. Asking what people want and finding ways to give it to them sounds simplistic, but it can result in "win-win" solutions in which everyone involved benefits. This document is a guide to using networking and surveys of residents to determine community needs. Some case studies show networking and surveys…

  11. Computer-Based Semantic Network in Molecular Biology: A Demonstration.

    ERIC Educational Resources Information Center

    Callman, Joshua L.; And Others

    This paper analyzes the hardware and software features that would be desirable in a computer-based semantic network system for representing biology knowledge. It then describes in detail a prototype network of molecular biology knowledge that has been developed using Filevision software and a Macintosh computer. The prototype contains about 100…

  12. Network motif-based method for identifying coronary artery disease

    PubMed Central

    LI, YIN; CONG, YAN; ZHAO, YUN

    2016-01-01

    The present study aimed to develop a more efficient method for identifying coronary artery disease (CAD) than the conventional method using individual differentially expressed genes (DEGs). GSE42148 gene microarray data were downloaded, preprocessed and screened for DEGs. Additionally, based on transcriptional regulation data obtained from ENCODE database and protein-protein interaction data from the HPRD, the common genes were downloaded and compared with genes annotated from gene microarrays to screen additional common genes in order to construct an integrated regulation network. FANMOD was then used to detect significant three-gene network motifs. Subsequently, GlobalAncova was used to screen differential three-gene network motifs between the CAD group and the normal control data from GSE42148. Genes involved in the differential network motifs were then subjected to functional annotation and pathway enrichment analysis. Finally, clustering analysis of the CAD and control samples was performed based on individual DEGs and the top 20 network motifs identified. In total, 9,008 significant three-node network motifs were detected from the integrated regulation network; these were categorized into 22 interaction modes, each containing a minimum of one transcription factor. Subsequently, 1,132 differential network motifs involving 697 genes were screened between the CAD and control group. The 697 genes were enriched in 154 gene ontology terms, including 119 biological processes, and 14 KEGG pathways. Identifying patients with CAD based on the top 20 network motifs provided increased accuracy compared with the conventional method based on individual DEGs. The results of the present study indicate that the network motif-based method is more efficient and accurate for identifying CAD patients than the conventional method based on individual DEGs. PMID:27347046

  13. Optical-Correlator Neural Network Based On Neocognitron

    NASA Technical Reports Server (NTRS)

    Chao, Tien-Hsin; Stoner, William W.

    1994-01-01

    Multichannel optical correlator implements shift-invariant, high-discrimination pattern-recognizing neural network based on paradigm of neocognitron. Selected as basic building block of this neural network because invariance under shifts is inherent advantage of Fourier optics included in optical correlators in general. Neocognitron is conceptual electronic neural-network model for recognition of visual patterns. Multilayer processing achieved by iteratively feeding back output of feature correlator to input spatial light modulator and updating Fourier filters. Neural network trained by use of characteristic features extracted from target images. Multichannel implementation enables parallel processing of large number of selected features.

  14. Diagnosis of helicopter gearboxes using structure-based networks

    NASA Technical Reports Server (NTRS)

    Jammu, Vinay B.; Danai, Kourosh; Lewicki, David G.

    1995-01-01

    A connectionist network is introduced for fault diagnosis of helicopter gearboxes that incorporates knowledge of the gearbox structure and characteristics of the vibration features as its fuzzy weights. Diagnosis is performed by propagating the abnormal features of vibration measurements through this Structure-Based Connectionist Network (SBCN), the outputs of which represent the fault possibility values for individual components of the gearbox. The performance of this network is evaluated by applying it to experimental vibration data from an OH-58A helicopter gearbox. The diagnostic results indicate that the network performance is comparable to those obtained from supervised pattern classification.

  15. Infections on Temporal Networks--A Matrix-Based Approach.

    PubMed

    Koher, Andreas; Lentz, Hartmut H K; Hövel, Philipp; Sokolov, Igor M

    2016-01-01

    We extend the concept of accessibility in temporal networks to model infections with a finite infectious period such as the susceptible-infected-recovered (SIR) model. This approach is entirely based on elementary matrix operations and unifies the disease and network dynamics within one algebraic framework. We demonstrate the potential of this formalism for three examples of networks with high temporal resolution: networks of social contacts, sexual contacts, and livestock-trade. Our investigations provide a new methodological framework that can be used, for instance, to estimate the epidemic threshold, a quantity that determines disease parameters, for which a large-scale outbreak can be expected. PMID:27035128

  16. CO2-neutral fuels

    NASA Astrophysics Data System (ADS)

    Goede, A. P. H.

    2015-08-01

    The need for storage of renewable energy (RE) generated by photovoltaic, concentrated solar and wind arises from the fact that supply and demand are ill-matched both geographically and temporarily. This already causes problems of overcapacity and grid congestion in countries where the fraction of RE exceeds the 20% level. A system approach is needed, which focusses not only on the energy source, but includes conversion, storage, transport, distribution, use and, last but not least, the recycling of waste. Furthermore, there is a need for more flexibility in the energy system, rather than relying on electrification, integration with other energy systems, for example the gas network, would yield a system less vulnerable to failure and better adapted to requirements. For example, long-term large-scale storage of electrical energy is limited by capacity, yet needed to cover weekly to seasonal demand. This limitation can be overcome by coupling the electricity net to the gas system, considering the fact that the Dutch gas network alone has a storage capacity of 552 TWh, sufficient to cover the entire EU energy demand for over a month. This lecture explores energy storage in chemicals bonds. The focus is on chemicals other than hydrogen, taking advantage of the higher volumetric energy density of hydrocarbons, in this case methane, which has an approximate 3.5 times higher volumetric energy density. More importantly, it allows the ready use of existing gas infrastructure for energy storage, transport and distribution. Intermittent wind electricity generated is converted into synthetic methane, the Power to Gas (P2G) scheme, by splitting feedstock CO2 and H2O into synthesis gas, a mixture of CO and H2. Syngas plays a central role in the synthesis of a range of hydrocarbon products, including methane, diesel and dimethyl ether. The splitting is accomplished by innovative means; plasmolysis and high-temperature solid oxygen electrolysis. A CO2-neutral fuel cycle is

  17. Hybrid network defense model based on fuzzy evaluation.

    PubMed

    Cho, Ying-Chiang; Pan, Jen-Yi

    2014-01-01

    With sustained and rapid developments in the field of information technology, the issue of network security has become increasingly prominent. The theme of this study is network data security, with the test subject being a classified and sensitive network laboratory that belongs to the academic network. The analysis is based on the deficiencies and potential risks of the network's existing defense technology, characteristics of cyber attacks, and network security technologies. Subsequently, a distributed network security architecture using the technology of an intrusion prevention system is designed and implemented. In this paper, first, the overall design approach is presented. This design is used as the basis to establish a network defense model, an improvement over the traditional single-technology model that addresses the latter's inadequacies. Next, a distributed network security architecture is implemented, comprising a hybrid firewall, intrusion detection, virtual honeynet projects, and connectivity and interactivity between these three components. Finally, the proposed security system is tested. A statistical analysis of the test results verifies the feasibility and reliability of the proposed architecture. The findings of this study will potentially provide new ideas and stimuli for future designs of network security architecture. PMID:24574870

  18. Hybrid Network Defense Model Based on Fuzzy Evaluation

    PubMed Central

    2014-01-01

    With sustained and rapid developments in the field of information technology, the issue of network security has become increasingly prominent. The theme of this study is network data security, with the test subject being a classified and sensitive network laboratory that belongs to the academic network. The analysis is based on the deficiencies and potential risks of the network's existing defense technology, characteristics of cyber attacks, and network security technologies. Subsequently, a distributed network security architecture using the technology of an intrusion prevention system is designed and implemented. In this paper, first, the overall design approach is presented. This design is used as the basis to establish a network defense model, an improvement over the traditional single-technology model that addresses the latter's inadequacies. Next, a distributed network security architecture is implemented, comprising a hybrid firewall, intrusion detection, virtual honeynet projects, and connectivity and interactivity between these three components. Finally, the proposed security system is tested. A statistical analysis of the test results verifies the feasibility and reliability of the proposed architecture. The findings of this study will potentially provide new ideas and stimuli for future designs of network security architecture. PMID:24574870

  19. Physical parameters collection based on wireless senor network

    NASA Astrophysics Data System (ADS)

    Chen, Xin; Wu, Hong; Ji, Lei

    2013-12-01

    With the development of sensor technology, wireless senor network has been applied in the medical, military, entertainment field and our daily life. But the existing available wireless senor networks applied in human monitoring system still have some problems, such as big power consumption, low security and so on. To improve senor network applied in health monitoring system, the paper introduces a star wireless senor networks based on msp430 and DSP. We design a low-cost heart-rate monitor senor node. The communication between senor node and sink node is realized according to the newest protocol proposed by the IEEE 802.15.6 Task Group. This wireless senor network will be more energy-efficient and faster compared to traditional senor networks.

  20. Graph-based pigment network detection in skin images

    NASA Astrophysics Data System (ADS)

    Sadeghi, M.; Razmara, M.; Ester, M.; Lee, T. K.; Atkins, M. S.

    2010-03-01

    Detecting pigmented network is a crucial step for melanoma diagnosis. In this paper, we present a novel graphbased pigment network detection method that can find and visualize round structures belonging to the pigment network. After finding sharp changes of the luminance image by an edge detection function, the resulting binary image is converted to a graph, and then all cyclic sub-graphs are detected. Theses cycles represent meshes that belong to the pigment network. Then, we create a new graph of the cyclic structures based on their distance. According to the density ratio of the new graph of the pigment network, the image is classified as "Absent" or "Present". Being Present means that a pigment network is detected in the skin lesion. Using this approach, we achieved an accuracy of 92.6% on five hundred unseen images.

  1. Ontology-Based Peer Exchange Network (OPEN)

    ERIC Educational Resources Information Center

    Dong, Hui

    2010-01-01

    In current Peer-to-Peer networks, distributed and semantic free indexing is widely used by systems adopting "Distributed Hash Table" ("DHT") mechanisms. Although such systems typically solve a. user query rather fast in a deterministic way, they only support a very narrow search scheme, namely the exact hash key match. Furthermore, DHT systems put…

  2. Network-Based Models in Molecular Biology

    NASA Astrophysics Data System (ADS)

    Beyer, Andreas

    Biological systems are characterized by a large number of diverse interactions. Interaction maps have been used to abstract those interactions at all biological scales ranging from food webs at the ecosystem level down to protein interaction networks at the molecular scale.

  3. A Tetraspecific VHH-Based Neutralizing Antibody Modifies Disease Outcome in Three Animal Models of Clostridium difficile Infection.

    PubMed

    Schmidt, Diane J; Beamer, Gillian; Tremblay, Jacqueline M; Steele, Jennifer A; Kim, Hyeun Bum; Wang, Yaunkai; Debatis, Michele; Sun, Xingmin; Kashentseva, Elena A; Dmitriev, Igor P; Curiel, David T; Shoemaker, Charles B; Tzipori, Saul

    2016-09-01

    Clostridium difficile infection (CDI), a leading cause of nosocomial infection, is a serious disease in North America, Europe, and Asia. CDI varies greatly from asymptomatic carriage to life-threatening diarrhea, toxic megacolon, and toxemia. The incidence of community-acquired infection has increased due to the emergence of hypervirulent antibiotic-resistant strains. These new strains contribute to the frequent occurrence of disease relapse, complicating treatment, increasing hospital stays, and increasing morbidity and mortality among patients. Therefore, it is critical to develop new therapeutic approaches that bypass the development of antimicrobial resistance and avoid disruption of gut microflora. Here, we describe the construction of a single heteromultimeric VHH-based neutralizing agent (VNA) that targets the two primary virulence factors of Clostridium difficile, toxins A (TcdA) and B (TcdB). Designated VNA2-Tcd, this agent has subnanomolar toxin neutralization potencies for both C. difficile toxins in cell assays. When given systemically by parenteral administration, VNA2-Tcd protected against CDI in gnotobiotic piglets and mice and to a lesser extent in hamsters. Protection from CDI was also observed in gnotobiotic piglets treated by gene therapy with an adenovirus that promoted the expression of VNA2-Tcd. PMID:27413067

  4. Neutralizing antibodies and broad, functional T cell immune response following immunization with hepatitis C virus proteins-based vaccine formulation.

    PubMed

    Martinez-Donato, Gillian; Amador-Cañizares, Yalena; Alvarez-Lajonchere, Liz; Guerra, Ivis; Pérez, Angel; Dubuisson, Jean; Wychowsk, Czeslaw; Musacchio, Alexis; Aguilar, Daylen; Dueñas-Carrera, Santiago

    2014-03-26

    HCV is a worldwide health problem despite the recent advances in the development of more effective therapies. No preventive vaccine is available against this pathogen. However, non-sterilizing immunity has been demonstrated and supports the potential success of HCV vaccines. Induction of cross-neutralizing antibodies and T cell responses targeting several conserved epitopes, have been related to hepatitis C virus (HCV) clearance. Therefore, in this work, the immunogenicity of a preparation (MixprotHC) based on protein variants of HCV Core, E1, E2 and NS3 was evaluated in mice and monkeys. IgG from MixprotHC immunized mice and monkeys neutralized the infectivity of heterologous HCVcc. Moreover, strong CD4+ and CD8+ T cells proliferative and IFN-γ secretion responses were elicited against HCV proteins. Remarkably, immunization with MixprotHC induced control of viremia in a surrogate challenge model in mice. These results suggest that MixprotHC might constitute an effective immunogen against HCV in humans with potential for reducing the likelihood of immune escape and viral persistence. PMID:24486345

  5. Evaluating conducting network based transparent electrodes from geometrical considerations

    NASA Astrophysics Data System (ADS)

    Kumar, Ankush; Kulkarni, G. U.

    2016-01-01

    Conducting nanowire networks have been developed as viable alternative to existing indium tin oxide based transparent electrode (TE). The nature of electrical conduction and process optimization for electrodes have gained much from the theoretical models based on percolation transport using Monte Carlo approach and applying Kirchhoff's law on individual junctions and loops. While most of the literature work pertaining to theoretical analysis is focussed on networks obtained from conducting rods (mostly considering only junction resistance), hardly any attention has been paid to those made using template based methods, wherein the structure of network is neither similar to network obtained from conducting rods nor similar to well periodic geometry. Here, we have attempted an analytical treatment based on geometrical arguments and applied image analysis on practical networks to gain deeper insight into conducting networked structure particularly in relation to sheet resistance and transmittance. Many literature examples reporting networks with straight or curvilinear wires with distributions in wire width and length have been analysed by treating the networks as two dimensional graphs and evaluating the sheet resistance based on wire density and wire width. The sheet resistance values from our analysis compare well with the experimental values. Our analysis on various examples has revealed that low sheet resistance is achieved with high wire density and compactness with straight rather than curvilinear wires and with narrower wire width distribution. Similarly, higher transmittance for given sheet resistance is possible with narrower wire width but of higher thickness, minimal curvilinearity, and maximum connectivity. For the purpose of evaluating active fraction of the network, the algorithm was made to distinguish and quantify current carrying backbone regions as against regions containing only dangling or isolated wires. The treatment can be helpful in predicting

  6. A PC-PCL-based control system for the high-voltage pulsed-power operation of the Intense Diagnostic Neutral Beam (IDNB) Experiment

    SciTech Connect

    Gribble, R.

    1993-06-01

    A stand-alone, semiautomated control system for the high-voltage pulsed-power energy sources on the Intense Diagnostic Neutral Beam Experiment at Los Alamos National Laboratory using personal computer (PC) and programmable logic controller (PLC) technology has been developed and implemented. The control system, consisting of a PC with the graphic operator interface, the network connecting the PC to the PLC, the PLC, the PLC I/O modules, fiber-optic interfaces and software, is described.

  7. Bioinspired Evolutionary Algorithm Based for Improving Network Coverage in Wireless Sensor Networks

    PubMed Central

    Abbasi, Mohammadjavad; Bin Abd Latiff, Muhammad Shafie

    2014-01-01

    Wireless sensor networks (WSNs) include sensor nodes in which each node is able to monitor the physical area and send collected information to the base station for further analysis. The important key of WSNs is detection and coverage of target area which is provided by random deployment. This paper reviews and addresses various area detection and coverage problems in sensor network. This paper organizes many scenarios for applying sensor node movement for improving network coverage based on bioinspired evolutionary algorithm and explains the concern and objective of controlling sensor node coverage. We discuss area coverage and target detection model by evolutionary algorithm. PMID:24693247

  8. Enhanced Weight based DSR for Mobile Ad Hoc Networks

    NASA Astrophysics Data System (ADS)

    Verma, Samant; Jain, Sweta

    2011-12-01

    Routing in ad hoc network is a great problematic, since a good routing protocol must ensure fast and efficient packet forwarding, which isn't evident in ad hoc networks. In literature there exists lot of routing protocols however they don't include all the aspects of ad hoc networks as mobility, device and medium constraints which make these protocols not efficient for some configuration and categories of ad hoc networks. Thus in this paper we propose an improvement of Weight Based DSR in order to include some of the aspects of ad hoc networks as stability, remaining battery power, load and trust factor and proposing a new approach Enhanced Weight Based DSR.

  9. Evolution based on chromosome affinity from a network perspective

    NASA Astrophysics Data System (ADS)

    Monteiro, R. L. S.; Fontoura, J. R. A.; Carneiro, T. K. G.; Moret, M. A.; Pereira, H. B. B.

    2014-06-01

    Recent studies have focused on models to simulate the complex phenomenon of evolution of species. Several studies have been performed with theoretical models based on Darwin's theories to associate them with the actual evolution of species. However, none of the existing models include the affinity between individuals using network properties. In this paper, we present a new model based on the concept of affinity. The model is used to simulate the evolution of species in an ecosystem composed of individuals and their relationships. We propose an evolutive algorithm that incorporates the degree centrality and efficiency network properties to perform the crossover process and to obtain the network topology objective, respectively. Using a real network as a starting point, we simulate its evolution and compare its results with the results of 5788 computer-generated networks.

  10. A network-based dynamical ranking system for competitive sports

    NASA Astrophysics Data System (ADS)

    Motegi, Shun; Masuda, Naoki

    2012-12-01

    From the viewpoint of networks, a ranking system for players or teams in sports is equivalent to a centrality measure for sports networks, whereby a directed link represents the result of a single game. Previously proposed network-based ranking systems are derived from static networks, i.e., aggregation of the results of games over time. However, the score of a player (or team) fluctuates over time. Defeating a renowned player in the peak performance is intuitively more rewarding than defeating the same player in other periods. To account for this factor, we propose a dynamic variant of such a network-based ranking system and apply it to professional men's tennis data. We derive a set of linear online update equations for the score of each player. The proposed ranking system predicts the outcome of the future games with a higher accuracy than the static counterparts.

  11. A network-based dynamical ranking system for competitive sports

    PubMed Central

    Motegi, Shun; Masuda, Naoki

    2012-01-01

    From the viewpoint of networks, a ranking system for players or teams in sports is equivalent to a centrality measure for sports networks, whereby a directed link represents the result of a single game. Previously proposed network-based ranking systems are derived from static networks, i.e., aggregation of the results of games over time. However, the score of a player (or team) fluctuates over time. Defeating a renowned player in the peak performance is intuitively more rewarding than defeating the same player in other periods. To account for this factor, we propose a dynamic variant of such a network-based ranking system and apply it to professional men's tennis data. We derive a set of linear online update equations for the score of each player. The proposed ranking system predicts the outcome of the future games with a higher accuracy than the static counterparts. PMID:23226590

  12. Evaluation of Network-Based Minimally Invasive VR Surgery Simulator.

    PubMed

    Tagawa, Kazuyoshi; Tanaka, Hiromi T; Kurumi, Yoshimasa; Komori, Masaru; Morikawa, Shigehiro

    2016-01-01

    In this paper, we report a result of an experiment of a field trial of our network-based minimally invasive surgery simulator. In our previous paper, we proposed a network-based visuohaptic surgery training system for laparoscopic surgery. In addition, we proposed a volume-based haptic communication approach, which allows participants at remote sites on the network to simultaneously interact with the same target object in virtual environments presented by multi-level computer performance systems, by only exchanging a small set of manipulation parameters for the target object and additional packet for synchronization of status of binary tree and deformation of shared volume model. We implemented the approach into our network-based surgery simulator, and field trial of the simulator at three locations was performed. PMID:27046613

  13. Polymeric membrane neutral phenol-sensitive electrodes for potentiometric G-quadruplex/hemin DNAzyme-based biosensing.

    PubMed

    Wang, Xuewei; Ding, Zhaofeng; Ren, Qingwei; Qin, Wei

    2013-02-01

    The first potentiometric transducer for G-quadruplex/hemin DNAzyme-based biosensing has been developed by using potential responses of electrically neutral oligomeric phenols on polymeric membrane electrodes. In the presence of G-quadruplex/hemin DNAzyme and H(2)O(2), monomeric phenols (e.g., phenol, methylphenols, and methoxyphenols) can be condensed into oligomeric phenols. Because both substrates and products are nonionic under optimal pH conditions, these reactions are traditionally not considered in designing potentiometric biosensing schemes. However, in this paper, the electrically neutral oligomeric phenols have been found to induce highly sensitive potential responses on quaternary ammonium salt-doped polymeric membrane electrodes owing to their high lipophilicities. In contrast, the potential responses to monomeric phenolic substrates are rather low. Thus, the G-quadruplex/hemin DNAzyme-catalyzed oxidative coupling of monomeric phenols can induce large potential signals, and the catalytic activities of DNAzymes can be probed. A comparison of potential responses induced by peroxidations of 13 monomeric phenols indicates that p-methoxyphenol is the most efficient substrate for potentiometric detection of G-quadruplex/hemin DNAzymes. Finally, two label-free and separation-free potentiometric DNA assay protocols based on the G-quadruplex/hemin DNAzyme have been developed with sensitivities higher than those of colorimetric and fluorometric methods. Coupled with other features such as reliable instrumentation, low cost, ease of miniaturization, and resistance to color and turbid interferences, the proposed polymeric membrane-based potentiometric sensor promises to be a competitive transducer for peroxidase-mimicking DNAzyme-involved biosensing. PMID:23289675

  14. Comparison of adaptive neuro-fuzzy inference system and artificial neutral networks model to categorize patients in the emergency department.

    PubMed

    Azeez, Dhifaf; Ali, Mohd Alauddin Mohd; Gan, Kok Beng; Saiboon, Ismail

    2013-01-01

    Unexpected disease outbreaks and disasters are becoming primary issues facing our world. The first points of contact either at the disaster scenes or emergency department exposed the frontline workers and medical physicians to the risk of infections. Therefore, there is a persuasive demand for the integration and exploitation of heterogeneous biomedical information to improve clinical practice, medical research and point of care. In this paper, a primary triage model was designed using two different methods: an adaptive neuro-fuzzy inference system (ANFIS) and artificial neural network (ANN).When the patient is presented at the triage counter, the system will capture their vital signs and chief complains beside physiology stat and general appearance of the patient. This data will be managed and analyzed in the data server and the patient's emergency status will be reported immediately. The proposed method will help to reduce the queue time at the triage counter and the emergency physician's burden especially duringdisease outbreak and serious disaster. The models have been built with 2223 data set extracted from the Emergency Department of the Universiti Kebangsaan Malaysia Medical Centre to predict the primary triage category. Multilayer feed forward with one hidden layer having 12 neurons has been used for the ANN architecture. Fuzzy subtractive clustering has been used to find the fuzzy rules for the ANFIS model. The results showed that the RMSE, %RME and the accuracy which evaluated by measuring specificity and sensitivity for binary classificationof the training data were 0.14, 5.7 and 99 respectively for the ANN model and 0.85, 32.00 and 96.00 respectively for the ANFIS model. As for unseen data the root mean square error, percentage the root mean square error and the accuracy for ANN is 0.18, 7.16 and 96.7 respectively, 1.30, 49.84 and 94 respectively for ANFIS model. The ANN model was performed better for both training and unseen data than ANFIS model in

  15. Analysis of amino acids network based on distance matrix

    NASA Astrophysics Data System (ADS)

    Ali, Tazid; Akhtar, Adil; Gohain, Nisha

    2016-06-01

    In this paper we have constructed a distance matrix of the amino acids. The distance is defined based on the relative evolutionary importance of the base position of the corresponding codons. From this distance matrix a network of the amino acids is obtained. We have argued that this network depicts the evolutionary pattern of the amino acids. To examine the relative importance of the amino acids with respect to this network we have discussed different measures of centrality. We have also investigated the correlation coefficients between different measures of centrality. Further we have explored clustering coefficient as well as degree of distribution.

  16. Implementation of the safety components base on industrial networks

    NASA Astrophysics Data System (ADS)

    Michalski, P.; Hetmańczyk, M. P.

    2015-11-01

    Capabilities of modern automation systems, especially in the field of industrial networks applications, encouraging them to favor during the process of developing the automation project [2,3,5]. Extensive network topologies and simplicity and clear structure causing displacement of the classic wiring. The article presents: project workflow for creating laboratory stand based on industrial network and base on it implementing the safety system. The individual steps of the process are described. In addition, the paper presents the main concept for controlling the safety functions of the system.

  17. Ionic liquid based multifunctional double network gel

    NASA Astrophysics Data System (ADS)

    Ahmed, Kumkum; Higashihara, Tomoya; Arafune, Hiroyuki; Kamijo, Toshio; Morinaga, Takashi; Sato, Takaya; Furukawa, Hidemitsu

    2015-04-01

    Gels are a promising class of soft and wet materials with diverse application in tissue engineering and bio-medical purpose. In order to accelerate the development of gels, it is required to synthesize multi-functional gels of high mechanical strength, ultra low surface friction and suitable elastic modulus with a variety of methods and new materials. Among many types of gel ionic gel made from ionic liquids (ILs) could be used for diverse applications in electrochemical devices and in the field of tribology. IL, a promising materials for lubrication, is a salt with a melting point lower than 100 °C. As a lubricant, ILs are characterized by an extremely low vapor pressure, high thermal stability and high ion conductivity. In this work a novel approach of making double network DN ionic gel using IL has been made utilizing photo polymerization process. A hydrophobic monomer Methyl methacrylate (MMA) has been used as a first network and a hydrophobic IL monomer, N,N-diethyl-N-(2-mthacryloylethyl)-N-methylammonium bistrifluoromethylsulfonyl)imide (DEMM-TFSI) has been used as a second network using photo initiator benzophenon and crosslinker triethylene glycol dimethacrylate (TEGDMA). The resulting DN ionic gel shows transparency, flexibility, high thermal stability, good mechanical toughness and low friction coefficient value which can be a potential candidate as a gel slider in different mechanical devices and can open a new area in the field of gel tribology.

  18. Epidemic Spreading in an Animal Trade Network - Comparison of Distance-Based and Network-Based Control Measures.

    PubMed

    Büttner, K; Krieter, J; Traulsen, A; Traulsen, I

    2016-02-01

    This study considered a simple SIR model for the spread of epidemics amongst holdings of a producer community in Northern Germany, based on the directed network of animal movements. The aim of this study was to evaluate the efficiency of different control measures to reduce the epidemic size substantially. The currently applied control measures based on the distance to an infected holding were compared with the control measures based on the specific network-based centrality parameters. We found that network-based measures led to a more efficient control of epidemics with a much smaller number of removed holdings. To assess the impact of different holding types, the analysed control measures were implemented by both including and excluding these holding types. The comparison revealed a crucial role of multipliers in the spread of an epidemic. The network-based control measures depending on the removal by out-degree, outgoing infection chain, betweenness centrality and outgoing closeness centrality showed the best results: In the three-year network, on average, 2.75, 4.15, 3.73 and 3.43 times more holdings had to be removed by the control measures based on the 1, 3, 5 and 10 km radius to reduce the epidemic to the same size compared with the network-based control measures. In an area with a higher holding density, the improvement of the network-based control measures may become even more obvious. The removal of holdings based on the above-mentioned centrality parameters did thus not only rapidly decompose the network into fragments, but also reduced the epidemic size most efficiently. PMID:25056832

  19. Content-Based Multi-Channel Network Coding Algorithm in the Millimeter-Wave Sensor Network.

    PubMed

    Lin, Kai; Wang, Di; Hu, Long

    2016-01-01

    With the development of wireless technology, the widespread use of 5G is already an irreversible trend, and millimeter-wave sensor networks are becoming more and more common. However, due to the high degree of complexity and bandwidth bottlenecks, the millimeter-wave sensor network still faces numerous problems. In this paper, we propose a novel content-based multi-channel network coding algorithm, which uses the functions of data fusion, multi-channel and network coding to improve the data transmission; the algorithm is referred to as content-based multi-channel network coding (CMNC). The CMNC algorithm provides a fusion-driven model based on the Dempster-Shafer (D-S) evidence theory to classify the sensor nodes into different classes according to the data content. By using the result of the classification, the CMNC algorithm also provides the channel assignment strategy and uses network coding to further improve the quality of data transmission in the millimeter-wave sensor network. Extensive simulations are carried out and compared to other methods. Our simulation results show that the proposed CMNC algorithm can effectively improve the quality of data transmission and has better performance than the compared methods. PMID:27376302

  20. Content-Based Multi-Channel Network Coding Algorithm in the Millimeter-Wave Sensor Network

    PubMed Central

    Lin, Kai; Wang, Di; Hu, Long

    2016-01-01

    With the development of wireless technology, the widespread use of 5G is already an irreversible trend, and millimeter-wave sensor networks are becoming more and more common. However, due to the high degree of complexity and bandwidth bottlenecks, the millimeter-wave sensor network still faces numerous problems. In this paper, we propose a novel content-based multi-channel network coding algorithm, which uses the functions of data fusion, multi-channel and network coding to improve the data transmission; the algorithm is referred to as content-based multi-channel network coding (CMNC). The CMNC algorithm provides a fusion-driven model based on the Dempster-Shafer (D-S) evidence theory to classify the sensor nodes into different classes according to the data content. By using the result of the classification, the CMNC algorithm also provides the channel assignment strategy and uses network coding to further improve the quality of data transmission in the millimeter-wave sensor network. Extensive simulations are carried out and compared to other methods. Our simulation results show that the proposed CMNC algorithm can effectively improve the quality of data transmission and has better performance than the compared methods. PMID:27376302

  1. Ensemble-Based Network Aggregation Improves the Accuracy of Gene Network Reconstruction

    PubMed Central

    Xiao, Guanghua; Xie, Yang

    2014-01-01

    Reverse engineering approaches to constructing gene regulatory networks (GRNs) based on genome-wide mRNA expression data have led to significant biological findings, such as the discovery of novel drug targets. However, the reliability of the reconstructed GRNs needs to be improved. Here, we propose an ensemble-based network aggregation approach to improving the accuracy of network topologies constructed from mRNA expression data. To evaluate the performances of different approaches, we created dozens of simulated networks from combinations of gene-set sizes and sample sizes and also tested our methods on three Escherichia coli datasets. We demonstrate that the ensemble-based network aggregation approach can be used to effectively integrate GRNs constructed from different studies – producing more accurate networks. We also apply this approach to building a network from epithelial mesenchymal transition (EMT) signature microarray data and identify hub genes that might be potential drug targets. The R code used to perform all of the analyses is available in an R package entitled “ENA”, accessible on CRAN (http://cran.r-project.org/web/packages/ENA/). PMID:25390635

  2. Mutual information-based LPI optimisation for radar network

    NASA Astrophysics Data System (ADS)

    Shi, Chenguang; Zhou, Jianjiang; Wang, Fei; Chen, Jun

    2015-07-01

    Radar network can offer significant performance improvement for target detection and information extraction employing spatial diversity. For a fixed number of radars, the achievable mutual information (MI) for estimating the target parameters may extend beyond a predefined threshold with full power transmission. In this paper, an effective low probability of intercept (LPI) optimisation algorithm is presented to improve LPI performance for radar network. Based on radar network system model, we first provide Schleher intercept factor for radar network as an optimisation metric for LPI performance. Then, a novel LPI optimisation algorithm is presented, where for a predefined MI threshold, Schleher intercept factor for radar network is minimised by optimising the transmission power allocation among radars in the network such that the enhanced LPI performance for radar network can be achieved. The genetic algorithm based on nonlinear programming (GA-NP) is employed to solve the resulting nonconvex and nonlinear optimisation problem. Some simulations demonstrate that the proposed algorithm is valuable and effective to improve the LPI performance for radar network.

  3. Event-driven approach of layered multicast to network adaptation in RED-based IP networks

    NASA Astrophysics Data System (ADS)

    Nahm, Kitae; Li, Qing; Kuo, C.-C. J.

    2003-11-01

    In this work, we investigate the congestion control problem for layered video multicast in IP networks of active queue management (AQM) using a simple random early detection (RED) queue model. AQM support from networks improves the visual quality of video streaming but makes network adaptation more di+/-cult for existing layered video multicast proticols that use the event-driven timer-based approach. We perform a simplified analysis on the response of the RED algorithm to burst traffic. The analysis shows that the primary problem lies in the weak correlation between the network feedback and the actual network congestion status when the RED queue is driven by burst traffic. Finally, a design guideline of the layered multicast protocol is proposed to overcome this problem.

  4. High performance network and channel-based storage

    NASA Technical Reports Server (NTRS)

    Katz, Randy H.

    1991-01-01

    In the traditional mainframe-centered view of a computer system, storage devices are coupled to the system through complex hardware subsystems called input/output (I/O) channels. With the dramatic shift towards workstation-based computing, and its associated client/server model of computation, storage facilities are now found attached to file servers and distributed throughout the network. We discuss the underlying technology trends that are leading to high performance network-based storage, namely advances in networks, storage devices, and I/O controller and server architectures. We review several commercial systems and research prototypes that are leading to a new approach to high performance computing based on network-attached storage.

  5. Degree-based attacks and defense strategies in complex networks

    NASA Astrophysics Data System (ADS)

    Yehezkel, Aviv; Cohen, Reuven

    2012-12-01

    We study the stability of random scale-free networks to degree-dependent attacks. We present analytical and numerical results to compute the critical fraction pc of nodes that need to be removed for destroying the network under this attack for different attack parameters. We study the effect of different defense strategies, based on the addition of a constant number of links on network robustness. We test defense strategies based on adding links to either low degree, middegree or high degree nodes. We find using analytical results and simulations that the middegree nodes defense strategy leads to the largest improvement to the network robustness against degree-based attacks. We also test these defense strategies on an internet autonomous systems map and obtain similar results.

  6. Degree-based attacks and defense strategies in complex networks.

    PubMed

    Yehezkel, Aviv; Cohen, Reuven

    2012-12-01

    We study the stability of random scale-free networks to degree-dependent attacks. We present analytical and numerical results to compute the critical fraction p_{c} of nodes that need to be removed for destroying the network under this attack for different attack parameters. We study the effect of different defense strategies, based on the addition of a constant number of links on network robustness. We test defense strategies based on adding links to either low degree, middegree or high degree nodes. We find using analytical results and simulations that the middegree nodes defense strategy leads to the largest improvement to the network robustness against degree-based attacks. We also test these defense strategies on an internet autonomous systems map and obtain similar results. PMID:23368011

  7. CD-Based Indices for Link Prediction in Complex Network.

    PubMed

    Wang, Tao; Wang, Hongjue; Wang, Xiaoxia

    2016-01-01

    Lots of similarity-based algorithms have been designed to deal with the problem of link prediction in the past decade. In order to improve prediction accuracy, a novel cosine similarity index CD based on distance between nodes and cosine value between vectors is proposed in this paper. Firstly, node coordinate matrix can be obtained by node distances which are different from distance matrix and row vectors of the matrix are regarded as coordinates of nodes. Then, cosine value between node coordinates is used as their similarity index. A local community density index LD is also proposed. Then, a series of CD-based indices include CD-LD-k, CD*LD-k, CD-k and CDI are presented and applied in ten real networks. Experimental results demonstrate the effectiveness of CD-based indices. The effects of network clustering coefficient and assortative coefficient on prediction accuracy of indices are analyzed. CD-LD-k and CD*LD-k can improve prediction accuracy without considering the assortative coefficient of network is negative or positive. According to analysis of relative precision of each method on each network, CD-LD-k and CD*LD-k indices have excellent average performance and robustness. CD and CD-k indices perform better on positive assortative networks than on negative assortative networks. For negative assortative networks, we improve and refine CD index, referred as CDI index, combining the advantages of CD index and evolutionary mechanism of the network model BA. Experimental results reveal that CDI index can increase prediction accuracy of CD on negative assortative networks. PMID:26752405

  8. CD-Based Indices for Link Prediction in Complex Network

    PubMed Central

    Wang, Tao; Wang, Hongjue; Wang, Xiaoxia

    2016-01-01

    Lots of similarity-based algorithms have been designed to deal with the problem of link prediction in the past decade. In order to improve prediction accuracy, a novel cosine similarity index CD based on distance between nodes and cosine value between vectors is proposed in this paper. Firstly, node coordinate matrix can be obtained by node distances which are different from distance matrix and row vectors of the matrix are regarded as coordinates of nodes. Then, cosine value between node coordinates is used as their similarity index. A local community density index LD is also proposed. Then, a series of CD-based indices include CD-LD-k, CD*LD-k, CD-k and CDI are presented and applied in ten real networks. Experimental results demonstrate the effectiveness of CD-based indices. The effects of network clustering coefficient and assortative coefficient on prediction accuracy of indices are analyzed. CD-LD-k and CD*LD-k can improve prediction accuracy without considering the assortative coefficient of network is negative or positive. According to analysis of relative precision of each method on each network, CD-LD-k and CD*LD-k indices have excellent average performance and robustness. CD and CD-k indices perform better on positive assortative networks than on negative assortative networks. For negative assortative networks, we improve and refine CD index, referred as CDI index, combining the advantages of CD index and evolutionary mechanism of the network model BA. Experimental results reveal that CDI index can increase prediction accuracy of CD on negative assortative networks. PMID:26752405

  9. Genetic-algorithm-based tri-state neural networks

    NASA Astrophysics Data System (ADS)

    Uang, Chii-Maw; Chen, Wen-Gong; Horng, Ji-Bin

    2002-09-01

    A new method, using genetic algorithms, for constructing a tri-state neural network is presented. The global searching features of the genetic algorithms are adopted to help us easily find the interconnection weight matrix of a bipolar neural network. The construction method is based on the biological nervous systems, which evolve the parameters encoded in genes. Taking the advantages of conventional (binary) genetic algorithms, a two-level chromosome structure is proposed for training the tri-state neural network. A Matlab program is developed for simulating the network performances. The results show that the proposed genetic algorithms method not only has the features of accurate of constructing the interconnection weight matrix, but also has better network performance.

  10. A Re-Examiniation of Phonological Neutralization.

    ERIC Educational Resources Information Center

    Dinnsen, D.

    1985-01-01

    Reviews research studies that raise serious questions about phonological neutralization, that is, the merger of a contrast in certain contexts. Some findings cast doubt on the very existence of neutralization and the correctness of the theoretical principles that make assumptions based on neutralization. Reanalyzes neutralization in light of these…

  11. Measurement of neutralizing serum antibodies of patients vaccinated with human papillomavirus L1 or L2-based immunogens using furin-cleaved HPV Pseudovirions.

    PubMed

    Wang, Joshua W; Jagu, Subhashini; Wang, Chenguang; Kitchener, Henry C; Daayana, Sai; Stern, Peter L; Pang, Susana; Day, Patricia M; Huh, Warner K; Roden, Richard B S

    2014-01-01

    Antibodies specific for neutralizing epitopes in either Human papillomavirus (HPV) capsid protein L1 or L2 can mediate protection from viral challenge and thus their accurate and sensitive measurement at high throughput is likely informative for monitoring response to prophylactic vaccination. Here we compare measurement of L1 and L2-specific neutralizing antibodies in human sera using the standard Pseudovirion-Based Neutralization Assay (L1-PBNA) with the newer Furin-Cleaved Pseudovirion-Based Neutralization Assay (FC-PBNA), a modification of the L1-PBNA intended to improve sensitivity towards L2-specific neutralizing antibodies without compromising assay of L1-specific responses. For detection of L1-specific neutralizing antibodies in human sera, the FC- PBNA and L1-PBNA assays showed similar sensitivity and a high level of correlation using WHO standard sera (n = 2), and sera from patients vaccinated with Gardasil (n = 30) or an experimental human papillomavirus type 16 (HPV16) L1 VLP vaccine (n = 70). The detection of L1-specific cross-neutralizing antibodies in these sera using pseudovirions of types phylogenetically-related to those targeted by the L1 virus-like particle (VLP) vaccines was also consistent between the two assays. However, for sera from patients (n = 17) vaccinated with an L2-based immunogen (TA-CIN), the FC-PBNA was more sensitive than the L1-PBNA in detecting L2-specific neutralizing antibodies. Further, the neutralizing antibody titers measured with the FC-PBNA correlated with those determined with the L2-PBNA, another modification of the L1-PBNA that spacio-temporally separates primary and secondary receptor engagement, as well as the protective titers measured using passive transfer studies in the murine genital-challenge model. In sum, the FC-PBNA provided sensitive measurement for both L1 VLP and L2-specific neutralizing antibody in human sera. Vaccination with TA-CIN elicits weak cross-protective antibody in a subset of

  12. Development of Novel Random Network Theory-Based Approaches to Identify Network Interactions among Nitrifying Bacteria

    SciTech Connect

    Shi, Cindy

    2015-07-17

    The interactions among different microbial populations in a community could play more important roles in determining ecosystem functioning than species numbers and their abundances, but very little is known about such network interactions at a community level. The goal of this project is to develop novel framework approaches and associated software tools to characterize the network interactions in microbial communities based on high throughput, large scale high-throughput metagenomics data and apply these approaches to understand the impacts of environmental changes (e.g., climate change, contamination) on network interactions among different nitrifying populations and associated microbial communities.

  13. Recommendations for the design, optimization, and qualification of cell-based assays used for the detection of neutralizing antibody responses elicited to biological therapeutics.

    PubMed

    Gupta, Shalini; Indelicato, Stephen R; Jethwa, Vijay; Kawabata, Thomas; Kelley, Marian; Mire-Sluis, Anthony R; Richards, Susan M; Rup, Bonita; Shores, Elizabeth; Swanson, Steven J; Wakshull, Eric

    2007-04-10

    The administration of biological therapeutics can evoke some level of immune response to the drug product in the receiving subjects. An immune response comprised of neutralizing antibodies can lead to loss of efficacy or potentially more serious clinical sequelae. Therefore, it is important to monitor the immunogenicity of biological therapeutics throughout the drug product development cycle. Immunoassays are typically used to screen for the presence and development of anti-drug product antibodies. However, in-vitro cell-based assays prove extremely useful for the characterization of immunoassay-positive samples to determine if the detected antibodies have neutralizing properties. This document provides scientific recommendations based on the experience of the authors for the development of cell-based assays for the detection of neutralizing antibodies in non-clinical and clinical studies. PMID:17307199

  14. VoIP attacks detection engine based on neural network

    NASA Astrophysics Data System (ADS)

    Safarik, Jakub; Slachta, Jiri

    2015-05-01

    The security is crucial for any system nowadays, especially communications. One of the most successful protocols in the field of communication over IP networks is Session Initiation Protocol. It is an open-source project used by different kinds of applications, both open-source and proprietary. High penetration and text-based principle made SIP number one target in IP telephony infrastructure, so security of SIP server is essential. To keep up with hackers and to detect potential malicious attacks, security administrator needs to monitor and evaluate SIP traffic in the network. But monitoring and following evaluation could easily overwhelm the security administrator in networks, typically in networks with a number of SIP servers, users and logically or geographically separated networks. The proposed solution lies in automatic attack detection systems. The article covers detection of VoIP attacks through a distributed network of nodes. Then the gathered data analyze aggregation server with artificial neural network. Artificial neural network means multilayer perceptron network trained with a set of collected attacks. Attack data could also be preprocessed and verified with a self-organizing map. The source data is detected by distributed network of detection nodes. Each node contains a honeypot application and traffic monitoring mechanism. Aggregation of data from each node creates an input for neural networks. The automatic classification on a centralized server with low false positive detection reduce the cost of attack detection resources. The detection system uses modular design for easy deployment in final infrastructure. The centralized server collects and process detected traffic. It also maintains all detection nodes.

  15. Artificial neural network based on SQUIDs: demonstration of network training and operation

    NASA Astrophysics Data System (ADS)

    Chiarello, F.; Carelli, P.; Castellano, M. G.; Torrioli, G.

    2013-12-01

    We propose a scheme for the realization of artificial neural networks based on superconducting quantum interference devices (SQUIDs). In order to demonstrate the operation of this scheme we designed and successfully tested a small network that implements an XOR gate and is trained by means of examples. The proposed scheme can be particularly convenient as support for superconducting applications such as detectors for astrophysics, high energy experiments, medicine imaging and so on.

  16. Fast Fragmentation of Networks Using Module-Based Attacks.

    PubMed

    Requião da Cunha, Bruno; González-Avella, Juan Carlos; Gonçalves, Sebastián

    2015-01-01

    In the multidisciplinary field of Network Science, optimization of procedures for efficiently breaking complex networks is attracting much attention from a practical point of view. In this contribution, we present a module-based method to efficiently fragment complex networks. The procedure firstly identifies topological communities through which the network can be represented using a well established heuristic algorithm of community finding. Then only the nodes that participate of inter-community links are removed in descending order of their betweenness centrality. We illustrate the method by applying it to a variety of examples in the social, infrastructure, and biological fields. It is shown that the module-based approach always outperforms targeted attacks to vertices based on node degree or betweenness centrality rankings, with gains in efficiency strongly related to the modularity of the network. Remarkably, in the US power grid case, by deleting 3% of the nodes, the proposed method breaks the original network in fragments which are twenty times smaller in size than the fragments left by betweenness-based attack. PMID:26569610

  17. Fast Fragmentation of Networks Using Module-Based Attacks

    PubMed Central

    Requião da Cunha, Bruno; González-Avella, Juan Carlos; Gonçalves, Sebastián

    2015-01-01

    In the multidisciplinary field of Network Science, optimization of procedures for efficiently breaking complex networks is attracting much attention from a practical point of view. In this contribution, we present a module-based method to efficiently fragment complex networks. The procedure firstly identifies topological communities through which the network can be represented using a well established heuristic algorithm of community finding. Then only the nodes that participate of inter-community links are removed in descending order of their betweenness centrality. We illustrate the method by applying it to a variety of examples in the social, infrastructure, and biological fields. It is shown that the module-based approach always outperforms targeted attacks to vertices based on node degree or betweenness centrality rankings, with gains in efficiency strongly related to the modularity of the network. Remarkably, in the US power grid case, by deleting 3% of the nodes, the proposed method breaks the original network in fragments which are twenty times smaller in size than the fragments left by betweenness-based attack. PMID:26569610

  18. Identification of Biochemical Network Modules Based on Shortest Retroactive Distances

    PubMed Central

    Sridharan, Gautham Vivek; Hassoun, Soha; Lee, Kyongbum

    2011-01-01

    Modularity analysis offers a route to better understand the organization of cellular biochemical networks as well as to derive practically useful, simplified models of these complex systems. While there is general agreement regarding the qualitative properties of a biochemical module, there is no clear consensus on the quantitative criteria that may be used to systematically derive these modules. In this work, we investigate cyclical interactions as the defining characteristic of a biochemical module. We utilize a round trip distance metric, termed Shortest Retroactive Distance (ShReD), to characterize the retroactive connectivity between any two reactions in a biochemical network and to group together network components that mutually influence each other. We evaluate the metric on two types of networks that feature feedback interactions: (i) epidermal growth factor receptor (EGFR) signaling and (ii) liver metabolism supporting drug transformation. For both networks, the ShReD partitions found hierarchically arranged modules that confirm biological intuition. In addition, the partitions also revealed modules that are less intuitive. In particular, ShReD-based partition of the metabolic network identified a ‘redox’ module that couples reactions of glucose, pyruvate, lipid and drug metabolism through shared production and consumption of NADPH. Our results suggest that retroactive interactions arising from feedback loops and metabolic cycles significantly contribute to the modularity of biochemical networks. For metabolic networks, cofactors play an important role as allosteric effectors that mediate the retroactive interactions. PMID:22102800

  19. Structural analysis of metabolic networks based on flux centrality.

    PubMed

    Koschützki, Dirk; Junker, Björn H; Schwender, Jörg; Schreiber, Falk

    2010-08-01

    Metabolic reactions are fundamental to living organisms, and a large number of reactions simultaneously occur at a given time in living cells transforming diverse metabolites into each other. There has been an ongoing debate on how to classify metabolites with respect to their importance for metabolic performance, usually based on the analysis of topological properties of genome scale metabolic networks. However, none of these studies have accounted quantitatively for flux in metabolic networks, thus lacking an important component of a cell's biochemistry. We therefore analyzed a genome scale metabolic network of Escherichia coli by comparing growth under 19 different growth conditions, using flux balance analysis and weighted network centrality investigation. With this novel concept of flux centrality we generated metabolite rankings for each particular growth condition. In contrast to the results of conventional analysis of genome scale metabolic networks, different metabolites were top-ranking dependent on the growth condition. At the same time, several metabolites were consistently among the high ranking ones. Those are associated with pathways that have been described by biochemists as the most central part of metabolism, such as glycolysis, tricarboxylic acid cycle and pentose phosphate pathway. The values for the average path length of the analyzed metabolite networks were between 10.5 and 12.6, supporting recent findings that the metabolic network of E. coli is not a small-world network. PMID:20471988

  20. General Chemistry Students' Conceptual Understanding and Language Fluency: Acid-Base Neutralization and Conductometry

    ERIC Educational Resources Information Center

    Nyachwaya, James M.

    2016-01-01

    The objective of this study was to examine college general chemistry students' conceptual understanding and language fluency in the context of the topic of acids and bases. 115 students worked in groups of 2-4 to complete an activity on conductometry, where they were given a scenario in which a titration of sodium hydroxide solution and dilute…

  1. Wealth Neutrality Revisited: Guaranteed Tax Base Formulas and Local Choice in Public Education.

    ERIC Educational Resources Information Center

    Reilly, Gilbert J.

    1982-01-01

    Proposes a model for evaluating state equalization aid formulas, accounting for municipal overburden and tradeoffs between expenditures and taxes. Tests the model using the Michigan state aid formula. Results relate elasticities to spending and tax levels and suggest that relatively unrestricted guaranteed tax base formulas can work. (PGD)

  2. Lévy flights in neutral fitness landscapes

    NASA Astrophysics Data System (ADS)

    Tomassini, Marco

    2016-04-01

    Regions of equal or close fitness are common in biological and artificial evolutionary systems. Customary hill-climbing optimizing paradigms turn out to be unsuitable to walk and search such large neutral networks. Here we propose a new technique to quickly jump out of neutral networks and to reach better fitness regions. The algorithm, based on Lévy flights, is compared to an established nearest neighbors random drift technique on two families of constructive neutral landscapes called the NKq and the NKp ensembles. The results of our numerical simulations clearly show that the new algorithm performs better than the nearest neighbors random drift for all studied landscapes. We conclude with some explanations of the observed behavior and some suggestions for the use of Lévy flights in more general search and optimization heuristics.

  3. A Cell Line-Based Neutralization Assay for Primary Human Immunodeficiency Virus Type 1 Isolates That Use either the CCR5 or the CXCR4 Coreceptor

    PubMed Central

    Trkola, Alexandra; Matthews, Jamie; Gordon, Cynthia; Ketas, Tom; Moore, John P.

    1999-01-01

    We describe here a cell line-based assay for the evaluation of human immunodeficiency virus type 1 (HIV-1) neutralization. The assay is based on CEM.NKR cells, transfected to express the HIV-1 coreceptor CCR5 to supplement the endogenous expression of CD4 and the CXCR4 coreceptor. The resulting CEM.NKR-CCR5 cells efficiently replicate primary HIV-1 isolates of both R5 and X4 phenotypes. A comparison of the CEM.NKR-CCR5 cells with mitogen-activated peripheral blood mononuclear cells (PBMC) in neutralization assays with sera from HIV-1-infected individuals or specific anti-HIV-1 monoclonal antibodies shows that the sensitivity of HIV-1 neutralization is similar in the two cell types. The CEM.NKR-CCR5 cell assay, however, is more convenient to perform and eliminates the donor-to-donor variation in HIV-1 replication efficiency, which is one of the principal drawbacks of the PBMC-based neutralization assay. We suggest that this new assay is suitable for the general measurement of HIV-1 neutralization by antibodies. PMID:10516002

  4. Network-based model of the growth of termite nests

    NASA Astrophysics Data System (ADS)

    Eom, Young-Ho; Perna, Andrea; Fortunato, Santo; Darrouzet, Eric; Theraulaz, Guy; Jost, Christian

    2015-12-01

    We present a model for the growth of the transportation network inside nests of the social insect subfamily Termitinae (Isoptera, termitidae). These nests consist of large chambers (nodes) connected by tunnels (edges). The model based on the empirical analysis of the real nest networks combined with pruning (edge removal, either random or weighted by betweenness centrality) and a memory effect (preferential growth from the latest added chambers) successfully predicts emergent nest properties (degree distribution, size of the largest connected component, average path lengths, backbone link ratios, and local graph redundancy). The two pruning alternatives can be associated with different genuses in the subfamily. A sensitivity analysis on the pruning and memory parameters indicates that Termitinae networks favor fast internal transportation over efficient defense strategies against ant predators. Our results provide an example of how complex network organization and efficient network properties can be generated from simple building rules based on local interactions and contribute to our understanding of the mechanisms that come into play for the formation of termite networks and of biological transportation networks in general.

  5. Energy Efficient Cluster Based Scheduling Scheme for Wireless Sensor Networks

    PubMed Central

    Srie Vidhya Janani, E.; Ganesh Kumar, P.

    2015-01-01

    The energy utilization of sensor nodes in large scale wireless sensor network points out the crucial need for scalable and energy efficient clustering protocols. Since sensor nodes usually operate on batteries, the maximum utility of network is greatly dependent on ideal usage of energy leftover in these sensor nodes. In this paper, we propose an Energy Efficient Cluster Based Scheduling Scheme for wireless sensor networks that balances the sensor network lifetime and energy efficiency. In the first phase of our proposed scheme, cluster topology is discovered and cluster head is chosen based on remaining energy level. The cluster head monitors the network energy threshold value to identify the energy drain rate of all its cluster members. In the second phase, scheduling algorithm is presented to allocate time slots to cluster member data packets. Here congestion occurrence is totally avoided. In the third phase, energy consumption model is proposed to maintain maximum residual energy level across the network. Moreover, we also propose a new packet format which is given to all cluster member nodes. The simulation results prove that the proposed scheme greatly contributes to maximum network lifetime, high energy, reduced overhead, and maximum delivery ratio. PMID:26495417

  6. Network-based model of the growth of termite nests.

    PubMed

    Eom, Young-Ho; Perna, Andrea; Fortunato, Santo; Darrouzet, Eric; Theraulaz, Guy; Jost, Christian

    2015-12-01

    We present a model for the growth of the transportation network inside nests of the social insect subfamily Termitinae (Isoptera, termitidae). These nests consist of large chambers (nodes) connected by tunnels (edges). The model based on the empirical analysis of the real nest networks combined with pruning (edge removal, either random or weighted by betweenness centrality) and a memory effect (preferential growth from the latest added chambers) successfully predicts emergent nest properties (degree distribution, size of the largest connected component, average path lengths, backbone link ratios, and local graph redundancy). The two pruning alternatives can be associated with different genuses in the subfamily. A sensitivity analysis on the pruning and memory parameters indicates that Termitinae networks favor fast internal transportation over efficient defense strategies against ant predators. Our results provide an example of how complex network organization and efficient network properties can be generated from simple building rules based on local interactions and contribute to our understanding of the mechanisms that come into play for the formation of termite networks and of biological transportation networks in general. PMID:26764747

  7. Genetic Algorithm Based Neural Networks for Nonlinear Optimization

    Energy Science and Technology Software Center (ESTSC)

    1994-09-28

    This software develops a novel approach to nonlinear optimization using genetic algorithm based neural networks. To our best knowledge, this approach represents the first attempt at applying both neural network and genetic algorithm techniques to solve a nonlinear optimization problem. The approach constructs a neural network structure and an appropriately shaped energy surface whose minima correspond to optimal solutions of the problem. A genetic algorithm is employed to perform a parallel and powerful search ofmore » the energy surface.« less

  8. Neural network based expert system for compressor stall monitoring

    NASA Technical Reports Server (NTRS)

    Lo, Ching F.; Shi, G. Z.

    1991-01-01

    This research is designed to apply a new information processing technology, artificial neural networks, to monitoring compressor stall. The outputs of neural networks support the dynamic knowledge data base of an expert system. This is the open-loop mode to avoid compressor stall. The integration of a control system with neural networks is the closed-loop mode in stall avoidance. The feasibility of the concept has been demonstrated for the compressor of 16-foot transonic/supersonic propulsion wind tunnels. The construction of a prototpye expert system has been initiated.

  9. An intelligent service-based network architecture for wearable robots.

    PubMed

    Lee, Ka Keung; Zhang, Ping; Xu, Yangsheng; Liang, Bin

    2004-08-01

    We are developing a novel robot concept called the wearable robot. Wearable robots are mobile information devices capable of supporting remote communication and intelligent interaction between networked entities. In this paper, we explore the possible functions of such a robotic network and will present a distributed network architecture based on service components. In order to support the interaction and communication between the components in the wearable robot system, we have developed an intelligent network architecture. This service-based architecture involves three major mechanisms. The first mechanism involves the use of a task coordinator service such that the execution of the services can be managed using a priority queue. The second mechanism enables the system to automatically push the required service proxy to the client intelligently based on certain system-related conditions. In the third mechanism, we allow the system to automatically deliver services based on contextual information. Using a fuzzy-logic-based decision making system, the matching service can determine whether the service should be automatically delivered utilizing the information provided by the service, client, lookup service, and context sensors. An application scenario has been implemented to demonstrate the feasibility of this distributed service-based robot architecture. The architecture is implemented as extensions to the Jini network model. PMID:15462452

  10. Microturbine control based on fuzzy neural network

    NASA Astrophysics Data System (ADS)

    Yan, Shijie; Bian, Chunyuan; Wang, Zhiqiang

    2006-11-01

    As microturbine generator (MTG) is a clean, efficient, low cost and reliable energy supply system. From outside characteristics of MTG, it is multi-variable, time-varying and coupling system, so it is difficult to be identified on-line and conventional control law adopted before cannot achieve desirable result. A novel fuzzy-neural networks (FNN) control algorithm was proposed in combining with the conventional PID control. In the paper, IF-THEN rules for tuning were applied by a first-order Sugeno fuzzy model with seven fuzzy rules and the membership function was given as the continuous GAUSSIAN function. Some sample data were utilized to train FNN. Through adjusting shape of membership function and weight continually, objective of auto-tuning fuzzy-rules can be achieved. The FNN algorithm had been applied to "100kW Microturbine control and power converter system". The results of simulation and experiment are shown that the algorithm can work very well.

  11. Neural network-based sensor signal accelerator.

    SciTech Connect

    Vogt, M. C.

    2000-10-16

    A strategy has been developed to computationally accelerate the response time of a generic electronic sensor. The strategy can be deployed as an algorithm in a control system or as a physical interface (on an embedded microcontroller) between a slower responding external sensor and a higher-speed control system. Optional code implementations are available to adjust algorithm performance when computational capability is limited. In one option, the actual sensor signal can be sampled at the slower rate with adaptive linear neural networks predicting the sensor's future output and interpolating intermediate synthetic output values. In another option, a synchronized collection of predictors sequentially controls the corresponding synthetic output voltage. Error is adaptively corrected in both options. The core strategy has been demonstrated with automotive oxygen sensor data. A prototype interface device is under construction. The response speed increase afforded by this strategy could greatly offset the cost of developing a replacement sensor with a faster physical response time.

  12. Optimized and enhanced DNA plasmid vector based in vivo construction of a neutralizing anti-HIV-1 envelope glycoprotein Fab.

    PubMed

    Muthumani, Kar; Flingai, Seleeke; Wise, Megan; Tingey, Colleen; Ugen, Kenneth E; Weiner, David B

    2013-10-01

    Monoclonal antibody preparations have demonstrated considerable clinical utility in the treatment of specific malignancies, as well as inflammatory and infectious diseases. Antibodies are conventionally delivered by passive administration, typically requiring costly large-scale laboratory development and production. Additional limitations include the necessity for repeat administrations, and the length of in vivo potency. Therefore, the development of methods to generate therapeutic antibodies and antibody like molecules in vivo, distinct from an active antigen-based immunization strategy, would have considerable clinical utility. In fact, adeno-associated viral (AAV) vector mediated delivery of immunoglobulin genes with subsequent generation of functional antibodies has recently been developed. As well, anon-viral vector mediated nucleic acid based delivery technology could permit the generation of therapeutic/prophylactic antibodies in vivo, obviating potential safety issues associated with viral vector based gene delivery. This delivery strategy has limitations as well, mainly due to very low in vivo production and expression of protein from the delivered gene. In the study reported here we have constructed an "enhanced and optimized" DNA plasmid technology to generate immunoglobulin heavy and light chains (i.e., Fab fragments) from an established neutralizing anti-HIV envelope glycoprotein monoclonal antibody (VRC01). This "enhanced" DNA (E-DNA) plasmid technology includes codon/RNA optimization, leader sequence utilization, as well as targeted potentiation of delivery and expression of the Fab immunoglobulin genes through use of "adaptive" in vivo electroporation. The results demonstrate that delivery by this method of a single administration of the optimized Fab expressing constructs resulted in generation of Fab molecules in mouse sera possessing high antigen specific binding and HIV neutralization activity for at least 7 d after injection, against diverse

  13. Optimized and enhanced DNA plasmid vector based in vivo construction of a neutralizing anti-HIV-1 envelope glycoprotein Fab

    PubMed Central

    Muthumani, Kar; Flingai, Seleeke; Wise, Megan; Tingey, Colleen; Ugen, Kenneth E; Weiner, David B

    2013-01-01

    Monoclonal antibody preparations have demonstrated considerable clinical utility in the treatment of specific malignancies, as well as inflammatory and infectious diseases. Antibodies are conventionally delivered by passive administration, typically requiring costly large-scale laboratory development and production. Additional limitations include the necessity for repeat administrations, and the length of in vivo potency. Therefore, the development of methods to generate therapeutic antibodies and antibody like molecules in vivo, distinct from an active antigen-based immunization strategy, would have considerable clinical utility. In fact, adeno-associated viral (AAV) vector mediated delivery of immunoglobulin genes with subsequent generation of functional antibodies has recently been developed. As well, anon-viral vector mediated nucleic acid based delivery technology could permit the generation of therapeutic/prophylactic antibodies in vivo, obviating potential safety issues associated with viral vector based gene delivery. This delivery strategy has limitations as well, mainly due to very low in vivo production and expression of protein from the delivered gene. In the study reported here we have constructed an “enhanced and optimized” DNA plasmid technology to generate immunoglobulin heavy and light chains (i.e., Fab fragments) from an established neutralizing anti-HIV envelope glycoprotein monoclonal antibody (VRC01). This “enhanced” DNA (E-DNA) plasmid technology includes codon/RNA optimization, leader sequence utilization, as well as targeted potentiation of delivery and expression of the Fab immunoglobulin genes through use of “adaptive” in vivo electroporation. The results demonstrate that delivery by this method of a single administration of the optimized Fab expressing constructs resulted in generation of Fab molecules in mouse sera possessing high antigen specific binding and HIV neutralization activity for at least 7 d after injection

  14. A silane pre-treatment for improving corrosion resistance performances of emeraldine base-coated aluminium samples in neutral environment

    NASA Astrophysics Data System (ADS)

    Cecchetto, Laura; Denoyelle, Alain; Delabouglise, Didier; Petit, Jean-Pierre

    2008-01-01

    An aluminium-magnesium alloy AA5182 substrate pre-treated with a 3-aminopropyl-triethoxysilane (APS)-based solution and coated with emeraldine base (EB) showed improved corrosion resistance to neutral salt spray test, compared to samples pre-treated with phosphoric acid-based solutions prior to the EB coating. Scanning electron microscopy (SEM) and energy dispersive X-ray spectrometry (EDX) characterisations of samples pre-treated with APS showed the presence of an uneven silane coating on the aluminium surface according to the surface microstructure. The potentiodynamic study performed on the EB-coated samples showed a noticeable reduction of corrosion current of coupons pre-treated with APS, while no relevant difference in corrosion behaviour was observed between APS and phosphoric acid pre-treated samples prior to the EB coating. The coupling activity of APS between the AA5182 surface and EB coating at the most sensitive corrosion sites could be responsible of an improved adhesion of the EB coating at these points and could explain the observed improved corrosion resistance.

  15. Design development of a neural network-based telemetry monitor

    NASA Technical Reports Server (NTRS)

    Lembeck, Michael F.

    1992-01-01

    This paper identifies the requirements and describes an architectural framework for an artificial neural network-based system that is capable of fulfilling monitoring and control requirements of future aerospace missions. Incorporated into this framework are a newly developed training algorithm and the concept of cooperative network architectures. The feasibility of such an approach is demonstrated for its ability to identify faults in low frequency waveforms.

  16. On effectiveness of network sensor-based defense framework

    NASA Astrophysics Data System (ADS)

    Zhang, Difan; Zhang, Hanlin; Ge, Linqiang; Yu, Wei; Lu, Chao; Chen, Genshe; Pham, Khanh

    2012-06-01

    Cyber attacks are increasing in frequency, impact, and complexity, which demonstrate extensive network vulnerabilities with the potential for serious damage. Defending against cyber attacks calls for the distributed collaborative monitoring, detection, and mitigation. To this end, we develop a network sensor-based defense framework, with the aim of handling network security awareness, mitigation, and prediction. We implement the prototypical system and show its effectiveness on detecting known attacks, such as port-scanning and distributed denial-of-service (DDoS). Based on this framework, we also implement the statistical-based detection and sequential testing-based detection techniques and compare their respective detection performance. The future implementation of defensive algorithms can be provisioned in our proposed framework for combating cyber attacks.

  17. Chain-based communication in cylindrical underwater wireless sensor networks.

    PubMed

    Javaid, Nadeem; Jafri, Mohsin Raza; Khan, Zahoor Ali; Alrajeh, Nabil; Imran, Muhammad; Vasilakos, Athanasios

    2015-01-01

    Appropriate network design is very significant for Underwater Wireless Sensor Networks (UWSNs). Application-oriented UWSNs are planned to achieve certain objectives. Therefore, there is always a demand for efficient data routing schemes, which can fulfill certain requirements of application-oriented UWSNs. These networks can be of any shape, i.e., rectangular, cylindrical or square. In this paper, we propose chain-based routing schemes for application-oriented cylindrical networks and also formulate mathematical models to find a global optimum path for data transmission. In the first scheme, we devise four interconnected chains of sensor nodes to perform data communication. In the second scheme, we propose routing scheme in which two chains of sensor nodes are interconnected, whereas in third scheme single-chain based routing is done in cylindrical networks. After finding local optimum paths in separate chains, we find global optimum paths through their interconnection. Moreover, we develop a computational model for the analysis of end-to-end delay. We compare the performance of the above three proposed schemes with that of Power Efficient Gathering System in Sensor Information Systems (PEGASIS) and Congestion adjusted PEGASIS (C-PEGASIS). Simulation results show that our proposed 4-chain based scheme performs better than the other selected schemes in terms of network lifetime, end-to-end delay, path loss, transmission loss, and packet sending rate. PMID:25658394

  18. Chain-Based Communication in Cylindrical Underwater Wireless Sensor Networks

    PubMed Central

    Javaid, Nadeem; Jafri, Mohsin Raza; Khan, Zahoor Ali; Alrajeh, Nabil; Imran, Muhammad; Vasilakos, Athanasios

    2015-01-01

    Appropriate network design is very significant for Underwater Wireless Sensor Networks (UWSNs). Application-oriented UWSNs are planned to achieve certain objectives. Therefore, there is always a demand for efficient data routing schemes, which can fulfill certain requirements of application-oriented UWSNs. These networks can be of any shape, i.e., rectangular, cylindrical or square. In this paper, we propose chain-based routing schemes for application-oriented cylindrical networks and also formulate mathematical models to find a global optimum path for data transmission. In the first scheme, we devise four interconnected chains of sensor nodes to perform data communication. In the second scheme, we propose routing scheme in which two chains of sensor nodes are interconnected, whereas in third scheme single-chain based routing is done in cylindrical networks. After finding local optimum paths in separate chains, we find global optimum paths through their interconnection. Moreover, we develop a computational model for the analysis of end-to-end delay. We compare the performance of the above three proposed schemes with that of Power Efficient Gathering System in Sensor Information Systems (PEGASIS) and Congestion adjusted PEGASIS (C-PEGASIS). Simulation results show that our proposed 4-chain based scheme performs better than the other selected schemes in terms of network lifetime, end-to-end delay, path loss, transmission loss, and packet sending rate. PMID:25658394

  19. Performance evaluation of a routing algorithm based on Hopfield Neural Network for network-on-chip

    NASA Astrophysics Data System (ADS)

    Esmaelpoor, Jamal; Ghafouri, Abdollah

    2015-12-01

    Network on chip (NoC) has emerged as a solution to overcome the system on chip growing complexity and design challenges. A proper routing algorithm is a key issue of an NoC design. An appropriate routing method balances load across the network channels and keeps path length as short as possible. This survey investigates the performance of a routing algorithm based on Hopfield Neural Network. It is a dynamic programming to provide optimal path and network monitoring in real time. The aim of this article is to analyse the possibility of using a neural network as a router. The algorithm takes into account the path with the lowest delay (cost) form source to destination. In other words, the path a message takes from source to destination depends on network traffic situation at the time and it is the fastest one. The simulation results show that the proposed approach improves average delay, throughput and network congestion efficiently. At the same time, the increase in power consumption is almost negligible.

  20. Metabolic Constraint-Based Refinement of Transcriptional Regulatory Networks

    PubMed Central

    Chandrasekaran, Sriram; Price, Nathan D.

    2013-01-01

    There is a strong need for computational frameworks that integrate different biological processes and data-types to unravel cellular regulation. Current efforts to reconstruct transcriptional regulatory networks (TRNs) focus primarily on proximal data such as gene co-expression and transcription factor (TF) binding. While such approaches enable rapid reconstruction of TRNs, the overwhelming combinatorics of possible networks limits identification of mechanistic regulatory interactions. Utilizing growth phenotypes and systems-level constraints to inform regulatory network reconstruction is an unmet challenge. We present our approach Gene Expression and Metabolism Integrated for Network Inference (GEMINI) that links a compendium of candidate regulatory interactions with the metabolic network to predict their systems-level effect on growth phenotypes. We then compare predictions with experimental phenotype data to select phenotype-consistent regulatory interactions. GEMINI makes use of the observation that only a small fraction of regulatory network states are compatible with a viable metabolic network, and outputs a regulatory network that is simultaneously consistent with the input genome-scale metabolic network model, gene expression data, and TF knockout phenotypes. GEMINI preferentially recalls gold-standard interactions (p-value = 10−172), significantly better than using gene expression alone. We applied GEMINI to create an integrated metabolic-regulatory network model for Saccharomyces cerevisiae involving 25,000 regulatory interactions controlling 1597 metabolic reactions. The model quantitatively predicts TF knockout phenotypes in new conditions (p-value = 10−14) and revealed potential condition-specific regulatory mechanisms. Our results suggest that a metabolic constraint-based approach can be successfully used to help reconstruct TRNs from high-throughput data, and highlights the potential of using a biochemically-detailed mechanistic framework

  1. Metabolic constraint-based refinement of transcriptional regulatory networks.

    PubMed

    Chandrasekaran, Sriram; Price, Nathan D

    2013-01-01

    There is a strong need for computational frameworks that integrate different biological processes and data-types to unravel cellular regulation. Current efforts to reconstruct transcriptional regulatory networks (TRNs) focus primarily on proximal data such as gene co-expression and transcription factor (TF) binding. While such approaches enable rapid reconstruction of TRNs, the overwhelming combinatorics of possible networks limits identification of mechanistic regulatory interactions. Utilizing growth phenotypes and systems-level constraints to inform regulatory network reconstruction is an unmet challenge. We present our approach Gene Expression and Metabolism Integrated for Network Inference (GEMINI) that links a compendium of candidate regulatory interactions with the metabolic network to predict their systems-level effect on growth phenotypes. We then compare predictions with experimental phenotype data to select phenotype-consistent regulatory interactions. GEMINI makes use of the observation that only a small fraction of regulatory network states are compatible with a viable metabolic network, and outputs a regulatory network that is simultaneously consistent with the input genome-scale metabolic network model, gene expression data, and TF knockout phenotypes. GEMINI preferentially recalls gold-standard interactions (p-value = 10(-172)), significantly better than using gene expression alone. We applied GEMINI to create an integrated metabolic-regulatory network model for Saccharomyces cerevisiae involving 25,000 regulatory interactions controlling 1597 metabolic reactions. The model quantitatively predicts TF knockout phenotypes in new conditions (p-value = 10(-14)) and revealed potential condition-specific regulatory mechanisms. Our results suggest that a metabolic constraint-based approach can be successfully used to help reconstruct TRNs from high-throughput data, and highlights the potential of using a biochemically-detailed mechanistic framework to

  2. SSL: Signal Similarity-Based Localization for Ocean Sensor Networks

    PubMed Central

    Chen, Pengpeng; Ma, Honglu; Gao, Shouwan; Huang, Yan

    2015-01-01

    Nowadays, wireless sensor networks are often deployed on the sea surface for ocean scientific monitoring. One of the important challenges is to localize the nodes’ positions. Existing localization schemes can be roughly divided into two types: range-based and range-free. The range-based localization approaches heavily depend on extra hardware capabilities, while range-free ones often suffer from poor accuracy and low scalability, far from the practical ocean monitoring applications. In response to the above limitations, this paper proposes a novel signal similarity-based localization (SSL) technology, which localizes the nodes’ positions by fully utilizing the similarity of received signal strength and the open-air characteristics of the sea surface. In the localization process, we first estimate the relative distance between neighboring nodes through comparing the similarity of received signal strength and then calculate the relative distance for non-neighboring nodes with the shortest path algorithm. After that, the nodes’ relative relation map of the whole network can be obtained. Given at least three anchors, the physical locations of nodes can be finally determined based on the multi-dimensional scaling (MDS) technology. The design is evaluated by two types of ocean experiments: a zonal network and a non-regular network using 28 nodes. Results show that the proposed design improves the localization accuracy compared to typical connectivity-based approaches and also confirm its effectiveness for large-scale ocean sensor networks. PMID:26610520

  3. SSL: Signal Similarity-Based Localization for Ocean Sensor Networks.

    PubMed

    Chen, Pengpeng; Ma, Honglu; Gao, Shouwan; Huang, Yan

    2015-01-01

    Nowadays, wireless sensor networks are often deployed on the sea surface for ocean scientific monitoring. One of the important challenges is to localize the nodes' positions. Existing localization schemes can be roughly divided into two types: range-based and range-free. The range-based localization approaches heavily depend on extra hardware capabilities, while range-free ones often suffer from poor accuracy and low scalability, far from the practical ocean monitoring applications. In response to the above limitations, this paper proposes a novel signal similarity-based localization (SSL) technology, which localizes the nodes' positions by fully utilizing the similarity of received signal strength and the open-air characteristics of the sea surface. In the localization process, we first estimate the relative distance between neighboring nodes through comparing the similarity of received signal strength and then calculate the relative distance for non-neighboring nodes with the shortest path algorithm. After that, the nodes' relative relation map of the whole network can be obtained. Given at least three anchors, the physical locations of nodes can be finally determined based on the multi-dimensional scaling (MDS) technology. The design is evaluated by two types of ocean experiments: a zonal network and a non-regular network using 28 nodes. Results show that the proposed design improves the localization accuracy compared to typical connectivity-based approaches and also confirm its effectiveness for large-scale ocean sensor networks. PMID:26610520

  4. MODEL-BASED CLUSTERING OF LARGE NETWORKS1

    PubMed Central

    Vu, Duy Q.; Hunter, David R.; Schweinberger, Michael

    2015-01-01

    We describe a network clustering framework, based on finite mixture models, that can be applied to discrete-valued networks with hundreds of thousands of nodes and billions of edge variables. Relative to other recent model-based clustering work for networks, we introduce a more flexible modeling framework, improve the variational-approximation estimation algorithm, discuss and implement standard error estimation via a parametric bootstrap approach, and apply these methods to much larger data sets than those seen elsewhere in the literature. The more flexible framework is achieved through introducing novel parameterizations of the model, giving varying degrees of parsimony, using exponential family models whose structure may be exploited in various theoretical and algorithmic ways. The algorithms are based on variational generalized EM algorithms, where the E-steps are augmented by a minorization-maximization (MM) idea. The bootstrapped standard error estimates are based on an efficient Monte Carlo network simulation idea. Last, we demonstrate the usefulness of the model-based clustering framework by applying it to a discrete-valued network with more than 131,000 nodes and 17 billion edge variables. PMID:26605002

  5. Study on automatic testing network based on LXI

    NASA Astrophysics Data System (ADS)

    Hu, Qin; Xu, Xing

    2006-11-01

    LXI (LAN eXtensions for Instrumentation), which is an extension of the widely used Ethernet technology in the automatic testing field, is the next generation instrumental platform. LXI standard is based on the industry standard Ethernet technolog, using the standard PC interface as the primary communication bus between devices. It implements the IEEE802.3 standard and supports TCP/IP protocol. LXI takes the advantage of the ease of use of GPIB-based instruments, the high performance and compact size of VXI/PXI instruments, and the flexibility and high throughput of Ethernet all at the same time. The paper firstly introduces the specification of LXI standard. Then, an automatic testing network architecture which is based on LXI platform is proposed. The automatic testing network is composed of several sets of LXI-based instruments, which are connected via an Ethernet switch or router. The network is computer-centric, and all the LXI-based instruments in the network are configured and initialized in computer. The computer controls the data acquisition, and displays the data on the screen. The instruments are using Ethernet connection as I/O interface, and can be triggered over a wired trigger interface, over LAN or over IEEE 1588 Precision Time Protocol running over the LAN interface. A hybrid automatic testing network comprised of LXI compliant devices and legacy instruments including LAN instruments as well as GPIB, VXI and PXI products connected via internal or external adaptors is also discussed at the end of the paper.

  6. Automated Induction Of Rule-Based Neural Networks

    NASA Technical Reports Server (NTRS)

    Smyth, Padhraic J.; Goodman, Rodney M.

    1994-01-01

    Prototype expert systems implemented in software and are functionally equivalent to neural networks set up automatically and placed into operation within minutes following information-theoretic approach to automated acquisition of knowledge from large example data bases. Approach based largely on use of ITRULE computer program.

  7. Pattern-based fault diagnosis using neural networks

    NASA Technical Reports Server (NTRS)

    Dietz, W. E.; Kiech, E. L.; Ali, M.

    1988-01-01

    An architecture for a real-time pattern-based diagnostic expert system capable of accommodating noisy, incomplete, and possibly erroneous input data is outlined. Results from prototype systems applied to jet and rocket engine fault diagnosis are presented. The ability of a neural network-based system to be trained via the presentation of behavioral patterns associated with fault conditions is demonstrated.

  8. Single-qubit gates based on targeted phase shifts in a 3D neutral atom array.

    PubMed

    Wang, Yang; Kumar, Aishwarya; Wu, Tsung-Yao; Weiss, David S

    2016-06-24

    Although the quality of individual quantum bits (qubits) and quantum gates has been steadily improving, the number of qubits in a single system has increased quite slowly. Here, we demonstrate arbitrary single-qubit gates based on targeted phase shifts, an approach that can be applied to atom, ion, or other atom-like systems. These gates are highly insensitive to addressing beam imperfections and have little cross-talk, allowing for a dramatic scaling up of qubit number. We have performed gates in series on 48 individually targeted sites in a 40% full 5 by 5 by 5 three-dimensional array created by an optical lattice. Using randomized benchmarking, we demonstrate an average gate fidelity of 0.9962(16), with an average cross-talk fidelity of 0.9979(2) (numbers in parentheses indicate the one standard deviation uncertainty in the final digits). PMID:27339984

  9. High Photothermal Activity within Neutral Nickel Dithiolene Complexes Derived from Imidazolium-Based Ionic Liquids.

    PubMed

    Mebrouk, Kenny; Camerel, Franck; Jeannin, Olivier; Heinrich, Benoit; Donnio, Bertrand; Fourmigué, Marc

    2016-02-01

    A new series of nickel N,N'-dialkylimidazolidine-2,4,5-trithione complexes ([Ni(R2timdt)2]) carrying linear or branched carbon chains (R = n-C4H9, n-C8H17, n-C12H25, n-C16H33, 2-ethylhexyl, 2-butyloctyl, phytanyl) have been obtained through an original synthetic pathway starting from easily available imidazolium-based ionic liquids. The chemical structures of these nickel complexes were confirmed by NMR and high-resolution mass spectroscopies as well as by X-ray analysis performed on single crystals. The complexes strongly absorb in the near-IR (NIR) region around 1000 nm, with high extinction coefficients reaching 80 000 M(-1) cm(-1). They are able to efficiently convert NIR light into heat under laser irradiation with very high photothermal conversion efficiencies (around 30%). PMID:26788960

  10. A global model of the neutral thermosphere in magnetic coordinates based on OGO 6 data

    NASA Technical Reports Server (NTRS)

    Stehle, C. G.; Nisbet, J. S.; Bleuler, E.

    1982-01-01

    Data from the OGO 6 satellite have been analyzed in magnetic latitude and magnetic local time coordinates for various seasons and magnetic activity levels. These measurements show considerable detail, particularly in the auroral regions where the energy inputs are well organized in this coordinate system. This detail is not readily observed in models based on geographic coordinates. Atomic oxygen and helium densities and a parameter related to the molecular nitrogen density were analyzed. The long-term averages of these quantities are presented in graphical form and as analytic functions to provide models of these thermospheric parameters. The atomic oxygen and helium densities show minima at high latitudes in the postmidnight sector for nearly all seasons and magnetic activity levels. The exospheric temperature inferred from the N2 density increases toward high latitudes for all seasons and all magnetic activity levels. This inferred temperature is about 300 deg K higher at the summer magnetic pole than at the winter magnetic pole.

  11. Density-based and transport-based core-periphery structures in networks

    NASA Astrophysics Data System (ADS)

    Lee, Sang Hoon; Cucuringu, Mihai; Porter, Mason A.

    2014-03-01

    Networks often possess mesoscale structures, and studying them can yield insights into both structure and function. It is most common to study community structure, but numerous other types of mesoscale structures also exist. In this paper, we examine core-periphery structures based on both density and transport. In such structures, core network components are well-connected both among themselves and to peripheral components, which are not well-connected to anything. We examine core-periphery structures in a wide range of examples of transportation, social, and financial networks—including road networks in large urban areas, a rabbit warren, a dolphin social network, a European interbank network, and a migration network between counties in the United States. We illustrate that a recently developed transport-based notion of node coreness is very useful for characterizing transportation networks. We also generalize this notion to examine core versus peripheral edges, and we show that the resulting diagnostic is also useful for transportation networks. To examine the properties of transportation networks further, we develop a family of generative models of roadlike networks. We illustrate the effect of the dimensionality of the embedding space on transportation networks, and we demonstrate that the correlations between different measures of coreness can be very different for different types of networks.

  12. Dynamic QoS Provisioning for Ethernet-based Networks

    NASA Astrophysics Data System (ADS)

    Angelopoulos, J.; Kanonakis, K.; Leligou, H. C.; Orfanoudakis, Th.; Katsigiannis, M.

    2008-11-01

    The evolution towards packet-based access networks and the importance of quality of experience brings the need for access networks that support the offer of a wide range of multimedia services not currently available to the desired extent. Legacy networks based on circuit switching used explicit signalling that travelled to all nodes along the path to book resources before the launce of the media stream. This approach does not scale well and is not in line with the philosophy of packet networks. Still, the need to reserve resources in advance remains since real-time services have limited if any means of adjusting their rates to the prevailing network conditions and to preserve customer satisfaction the traditional preventive approach that needs accurate estimates of resource needs for the duration of the session is the only option. The paper describes a possible CAC solution based on measuring flows and enriches the network with implicit admission control (without obviating explicit control if available) and can manage resource allocation to protect quality-demanding services from degradation. The basis is a flow measurement system, which will estimate the traffic load produced by the flow and activate admission control. However, because in most cases these initial indication may well be misleading, it will be cross checked against a database of previously recorded flows per customer interface which can provide long term data on the flows leaving only a few cases that have to be corrected on the fly. The overall product is a self-learning autonomic system that supports QoS in the access network for services that do not communicate with the network layer such as, for example, peer-to-peer real-time multimedia applications.

  13. Pharmaceutical quality control of acid and neutral drugs based on competitive self-assembly in amphiphilic systems.

    PubMed

    Pedraza, Ana; Sicilia, María Dolores; Rubio, Soledad; Pérez-Bendito, Dolores

    2006-01-01

    An aggregation parameter-based methodology for determining acid and neutral drugs in pharmaceutical dosage forms is presented. The method is based on competitive self-assembly in ternary dye-surfactant-drug aqueous mixtures. Dyes bearing charge of opposite sign to that of surfactants bind to surfactant to form mixed dye-surfactant aggregates, which are monitored from changes in the spectra features of the dye. The drug competes with the dye to interact with the surfactant to form drug-surfactant aggregates, which results in a decrease in the surfactant to dye binding degree proportional to the drug concentration in the aqueous solution. Coomassie Brilliant Blue G (CBBG) and didodecyldimethylammonium bromide (DDABr) were the dye and surfactant reactant used, respectively. The suitability of the surfactant to dye binding degree (SDBD) method to determine drugs with very different molecular structure: propionic (flurbiprofen, ibuprofen, naproxen and ketoprofen) and acetic (diclofenac, felbinac and zomepirac) acids, indolines (indomethacin and sulindac), glycyrrhetinic acid derivatives (carbenoxolone and enoxolone), salicylates (diflunisal and phenyl salicylate), oxicams (meloxicam, piroxicam and tenoxicam), pyrazolones (phenylbutazone and sulfinpyrazone) and hydrocortisones (dexamethasone and prednisolone) has been proved. The proposed method was successfully applied to the determination of drugs in commercial formulates (effervescent granulates, tablets, suppositories, gels and blisters) with a minimum sample treatment (dilution of liquid samples and dissolution of solid samples). PMID:16365667

  14. Value-based insurance design program in north Carolina increased medication adherence but was not cost neutral.

    PubMed

    Maciejewski, Matthew L; Wansink, Daryl; Lindquist, Jennifer H; Parker, John C; Farley, Joel F

    2014-02-01

    Value-based insurance design (VBID) has shown promise for improving medication adherence by lowering or eliminating patients' payments for some medications. Yet the business case for VBID remains unclear. VBID is based on the premise that higher medication and administrative expenses incurred by insurers will be offset by lower nonmedication expenditures that result from better disease control. This article examines Blue Cross Blue Shield of North Carolina's VBID program, which began in 2008. The program eliminated copayments for generic medications and reduced copays for brand-name medications. Patient adherence improved 2.7-3.4 percent during the two-year study period. Hospital admissions decreased modestly, but there were no significant changes in emergency department use or total health expenditures. The insurer incurred $6.4 million in higher medication expenditures; total nonmedication expenditures for the study population decreased $5.7 million. Our results provide limited support for the idea that VBID can be cost-neutral in specific subpopulations. The business case for VBID may be more compelling over the long term and in high risk subgroups for whose members cost is an important barrier to improved medication adherence. PMID:24493774

  15. Fiber-optic pH sensor based on sol-gel film immobilized with neutral red

    NASA Astrophysics Data System (ADS)

    Jeon, Dayeong; Yoo, Wook Jae; Seo, Jeong Ki; Shin, Sang Hun; Han, Ki-Tek; Kim, Seon Geun; Park, Jang-Yeon; Lee, Bongsoo

    2013-03-01

    In this study, we developed a fiber-optic pH sensor based on a sol-gel film immobilized with neutral red (NR). A solgel film was prepared by mixing tetramethylorthosilicate (TMOS), trimethoxymethylsilane (MTMS), ethanol (EtOH), distilled water (H2O), and NR powder. Accordingly, the thin pH sol-gel film was fabricated through a sol-gel process with a dip-coating method. The thickness and diameter of the fabricated pH sol-gel film are 0.11 and 0.6 mm, respectively. We measured the optical absorbance and the light intensity with the spectra of reflected light, which change with the color variation of the pH sol-gel film in the fiber-optic sensing probe. From the experimental results, we demonstrated that the proposed fiber-optic pH sensor has good reversibility, reproducibility, and a fast response time, in which the optical properties of the NR-based pH sol-gel film change with the pH value.

  16. Bicriteria Network Optimization Problem using Priority-based Genetic Algorithm

    NASA Astrophysics Data System (ADS)

    Gen, Mitsuo; Lin, Lin; Cheng, Runwei

    Network optimization is being an increasingly important and fundamental issue in the fields such as engineering, computer science, operations research, transportation, telecommunication, decision support systems, manufacturing, and airline scheduling. In many applications, however, there are several criteria associated with traversing each edge of a network. For example, cost and flow measures are both important in the networks. As a result, there has been recent interest in solving Bicriteria Network Optimization Problem. The Bicriteria Network Optimization Problem is known a NP-hard. The efficient set of paths may be very large, possibly exponential in size. Thus the computational effort required to solve it can increase exponentially with the problem size in the worst case. In this paper, we propose a genetic algorithm (GA) approach used a priority-based chromosome for solving the bicriteria network optimization problem including maximum flow (MXF) model and minimum cost flow (MCF) model. The objective is to find the set of Pareto optimal solutions that give possible maximum flow with minimum cost. This paper also combines Adaptive Weight Approach (AWA) that utilizes some useful information from the current population to readjust weights for obtaining a search pressure toward a positive ideal point. Computer simulations show the several numerical experiments by using some difficult-to-solve network design problems, and show the effectiveness of the proposed method.

  17. Earthquake networks based on space-time influence domain

    NASA Astrophysics Data System (ADS)

    He, Xuan; Zhao, Hai; Cai, Wei; Liu, Zheng; Si, Shuai-Zong

    2014-08-01

    A new construction method of earthquake networks based on the theory of complex networks is presented in this paper. We propose a space-time influence domain for each earthquake to quantify the subsequence of earthquakes which are directly influenced by the former earthquake. The size of the domain is according to the magnitude of earthquake. In this way, the seismic data in the region of California are mapped to a topology of earthquake network. It is discovered that the earthquake networks in different time spans behave as scale-free networks. This result can be interpreted in terms of the Gutenberg-Richter law. Discovery of small-world characteristic is also reported on the earthquake network constructed by our method. The Omori law emerges as a feature of seismicity for the out-going links of the network. These characteristics highlight a novel aspect of seismicity as a complex phenomenon and will help us to reveal the internal mechanism of seismic system.

  18. Analysing the Correlation between Social Network Analysis Measures and Performance of Students in Social Network-Based Engineering Education

    ERIC Educational Resources Information Center

    Putnik, Goran; Costa, Eric; Alves, Cátia; Castro, Hélio; Varela, Leonilde; Shah, Vaibhav

    2016-01-01

    Social network-based engineering education (SNEE) is designed and implemented as a model of Education 3.0 paradigm. SNEE represents a new learning methodology, which is based on the concept of social networks and represents an extended model of project-led education. The concept of social networks was applied in the real-life experiment,…

  19. A global model of the neutral thermosphere in magnetic coordinates based on AE-C data

    NASA Technical Reports Server (NTRS)

    Stehle, C. G.

    1980-01-01

    An empirical model of the global atomic oxygen and helium distributions in the thermosphere is developed in a magnetic coordinate system and compared to similar models which are expanded in geographic coordinates. The advantage of using magnetic coordinates is that fewer terms are needed to make predictions which are nearly identical to those which would be obtained from a geographic model with longitudinal and universal time corrections. Magnetic coordinates are more directly related to the major energy inputs in the polar regions than geographic coordinates and are more convenient to use in studies of high latitude energy deposition processes. This is important for comparison with theoretical models where the number of coordinates is limited. The effect of magnetic activity on the atomic oxygen distribution in the morning sector of the high latitude thermosphere in the auroral zone is also considered. A magnetic activity indicator (ML) based on an auroral electrojet index (AL) and the 3 hour ap index are used to relate the atomic oxygen density variations to magnetic activity in this region.

  20. Similarity-Based Classification in Partially Labeled Networks

    NASA Astrophysics Data System (ADS)

    Zhang, Qian-Ming; Shang, Ming-Sheng; Lü, Linyuan

    Two main difficulties in the problem of classification in partially labeled networks are the sparsity of the known labeled nodes and inconsistency of label information. To address these two difficulties, we propose a similarity-based method, where the basic assumption is that two nodes are more likely to be categorized into the same class if they are more similar. In this paper, we introduce ten similarity indices defined based on the network structure. Empirical results on the co-purchase network of political books show that the similarity-based method can, to some extent, overcome these two difficulties and give higher accurate classification than the relational neighbors method, especially when the labeled nodes are sparse. Furthermore, we find that when the information of known labeled nodes is sufficient, the indices considering only local information can perform as good as those global indices while having much lower computational complexity.

  1. Signalprint-Based Intrusion Detection in Wireless Networks

    NASA Astrophysics Data System (ADS)

    Mitchell, Rob; Chen, Ing-Ray; Eltoweissy, Mohamed

    Wireless networks are a critical part of global communication for which intrusion detection techniques should be applied to secure network access, or the cost associated with successful attacks will overshadow the benefits that wireless networks offer. In this paper we investigate a new scheme called Nodeprints to extend the existing centralized Signalprints design for authentication to a distributed voting-based design for intrusion detection. We analyze the effect of voting-based intrusion detection designs, the probability of an individual node voting incorrectly, the ratio of mobile nodes to base stations, and the rate at which nodes are compromised, on the system performance measured by the probability that the intrusion detection system yields a false result. We develop a performance model for evaluating our Nodeprints design and identify conditions under which Nodeprints outperforms the existing Signalprints design.

  2. Analog neural network-based helicopter gearbox health monitoring system.

    PubMed

    Monsen, P T; Dzwonczyk, M; Manolakos, E S

    1995-12-01

    The development of a reliable helicopter gearbox health monitoring system (HMS) has been the subject of considerable research over the past 15 years. The deployment of such a system could lead to a significant saving in lives and vehicles as well as dramatically reduce the cost of helicopter maintenance. Recent research results indicate that a neural network-based system could provide a viable solution to the problem. This paper presents two neural network-based realizations of an HMS system. A hybrid (digital/analog) neural system is proposed as an extremely accurate off-line monitoring tool used to reduce helicopter gearbox maintenance costs. In addition, an all analog neural network is proposed as a real-time helicopter gearbox fault monitor that can exploit the ability of an analog neural network to directly compute the discrete Fourier transform (DFT) as a sum of weighted samples. Hardware performance results are obtained using the Integrated Neural Computing Architecture (INCA/1) analog neural network platform that was designed and developed at The Charles Stark Draper Laboratory. The results indicate that it is possible to achieve a 100% fault detection rate with 0% false alarm rate by performing a DFT directly on the first layer of INCA/1 followed by a small-size two-layer feed-forward neural network and a simple post-processing majority voting stage. PMID:8550948

  3. Router Agent Technology for Policy-Based Network Management

    NASA Technical Reports Server (NTRS)

    Chow, Edward T.; Sudhir, Gurusham; Chang, Hsin-Ping; James, Mark; Liu, Yih-Chiao J.; Chiang, Winston

    2011-01-01

    This innovation can be run as a standalone network application on any computer in a networked environment. This design can be configured to control one or more routers (one instance per router), and can also be configured to listen to a policy server over the network to receive new policies based on the policy- based network management technology. The Router Agent Technology transforms the received policies into suitable Access Control List syntax for the routers it is configured to control. It commits the newly generated access control lists to the routers and provides feedback regarding any errors that were faced. The innovation also automatically generates a time-stamped log file regarding all updates to the router it is configured to control. This technology, once installed on a local network computer and started, is autonomous because it has the capability to keep listening to new policies from the policy server, transforming those policies to router-compliant access lists, and committing those access lists to a specified interface on the specified router on the network with any error feedback regarding commitment process. The stand-alone application is named RouterAgent and is currently realized as a fully functional (version 1) implementation for the Windows operating system and for CISCO routers.

  4. Network-based reading system for lung cancer screening CT

    NASA Astrophysics Data System (ADS)

    Fujino, Yuichi; Fujimura, Kaori; Nomura, Shin-ichiro; Kawashima, Harumi; Tsuchikawa, Megumu; Matsumoto, Toru; Nagao, Kei-ichi; Uruma, Takahiro; Yamamoto, Shinji; Takizawa, Hotaka; Kuroda, Chikazumi; Nakayama, Tomio

    2006-03-01

    This research aims to support chest computed tomography (CT) medical checkups to decrease the death rate by lung cancer. We have developed a remote cooperative reading system for lung cancer screening over the Internet, a secure transmission function, and a cooperative reading environment. It is called the Network-based Reading System. A telemedicine system involves many issues, such as network costs and data security if we use it over the Internet, which is an open network. In Japan, broadband access is widespread and its cost is the lowest in the world. We developed our system considering human machine interface and security. It consists of data entry terminals, a database server, a computer aided diagnosis (CAD) system, and some reading terminals. It uses a secure Digital Imaging and Communication in Medicine (DICOM) encrypting method and Public Key Infrastructure (PKI) based secure DICOM image data distribution. We carried out an experimental trial over the Japan Gigabit Network (JGN), which is the testbed for the Japanese next-generation network, and conducted verification experiments of secure screening image distribution, some kinds of data addition, and remote cooperative reading. We found that network bandwidth of about 1.5 Mbps enabled distribution of screening images and cooperative reading and that the encryption and image distribution methods we proposed were applicable to the encryption and distribution of general DICOM images via the Internet.

  5. Applying Model Based Systems Engineering to NASA's Space Communications Networks

    NASA Technical Reports Server (NTRS)

    Bhasin, Kul; Barnes, Patrick; Reinert, Jessica; Golden, Bert

    2013-01-01

    System engineering practices for complex systems and networks now require that requirement, architecture, and concept of operations product development teams, simultaneously harmonize their activities to provide timely, useful and cost-effective products. When dealing with complex systems of systems, traditional systems engineering methodology quickly falls short of achieving project objectives. This approach is encumbered by the use of a number of disparate hardware and software tools, spreadsheets and documents to grasp the concept of the network design and operation. In case of NASA's space communication networks, since the networks are geographically distributed, and so are its subject matter experts, the team is challenged to create a common language and tools to produce its products. Using Model Based Systems Engineering methods and tools allows for a unified representation of the system in a model that enables a highly related level of detail. To date, Program System Engineering (PSE) team has been able to model each network from their top-level operational activities and system functions down to the atomic level through relational modeling decomposition. These models allow for a better understanding of the relationships between NASA's stakeholders, internal organizations, and impacts to all related entities due to integration and sustainment of existing systems. Understanding the existing systems is essential to accurate and detailed study of integration options being considered. In this paper, we identify the challenges the PSE team faced in its quest to unify complex legacy space communications networks and their operational processes. We describe the initial approaches undertaken and the evolution toward model based system engineering applied to produce Space Communication and Navigation (SCaN) PSE products. We will demonstrate the practice of Model Based System Engineering applied to integrating space communication networks and the summary of its

  6. Attribute-based edge bundling for visualizing social networks

    NASA Astrophysics Data System (ADS)

    Guo, Lin; Zuo, Wanli; Peng, Tao; Adhikari, Binod Kumar

    2015-11-01

    Most nodes in complex networks have multiple attributes, which make them hard to analyze. Because general edge bundling algorithms fail to handle complex networks as a result of their intricate features, network simplification is extremely important. This paper proposes an attribute-based edge bundling algorithm that displays similar edges in nearby locations. Meanwhile, by analyzing complex networks at a community level, the overlapping clustering of nodes is well implemented, and better clustering effects can be achieved by grouping similar edges together. On the basis of datasets with different types and sizes, the experiments illustrate the simplification degree of the intricate graphs created by the algorithm proposed, which outperforms established competitors in correctness and effectiveness.

  7. Yarn Quality Prediction Based on Improved BP Neural Network

    NASA Astrophysics Data System (ADS)

    Yang, Jian-Guo; Xiong, Jing-Wei; Xun, Lan

    Aiming at the key quality indexes xbt in spinning processing is caused by many complex and interactions factors. A xbt prediction model is put forward based on the PSO-BP neural network, which adjusts weights of BP neural network using particle swarm optimization (PSO) rather than the traditional gradient descent method, is used to improve the convergence speed of neural network and the ability of getting the global optimal solution. As the object of a large number of field detection data in a spinning workshop, the results show that, compared with the traditional BP algorithm and GA-BP algorithm, the PSO-BP neural network can obvious improve yarn quality prediction model precision and stability.

  8. Neural Network-Based Sensor Validation for Turboshaft Engines

    NASA Technical Reports Server (NTRS)

    Moller, James C.; Litt, Jonathan S.; Guo, Ten-Huei

    1998-01-01

    Sensor failure detection, isolation, and accommodation using a neural network approach is described. An auto-associative neural network is configured to perform dimensionality reduction on the sensor measurement vector and provide estimated sensor values. The sensor validation scheme is applied in a simulation of the T700 turboshaft engine in closed loop operation. Performance is evaluated based on the ability to detect faults correctly and maintain stable and responsive engine operation. The set of sensor outputs used for engine control forms the network input vector. Analytical redundancy is verified by training networks of successively smaller bottleneck layer sizes. Training data generation and strategy are discussed. The engine maintained stable behavior in the presence of sensor hard failures. With proper selection of fault determination thresholds, stability was maintained in the presence of sensor soft failures.

  9. A Security Assessment Mechanism for Software-Defined Networking-Based Mobile Networks

    PubMed Central

    Luo, Shibo; Dong, Mianxiong; Ota, Kaoru; Wu, Jun; Li, Jianhua

    2015-01-01

    Software-Defined Networking-based Mobile Networks (SDN-MNs) are considered the future of 5G mobile network architecture. With the evolving cyber-attack threat, security assessments need to be performed in the network management. Due to the distinctive features of SDN-MNs, such as their dynamic nature and complexity, traditional network security assessment methodologies cannot be applied directly to SDN-MNs, and a novel security assessment methodology is needed. In this paper, an effective security assessment mechanism based on attack graphs and an Analytic Hierarchy Process (AHP) is proposed for SDN-MNs. Firstly, this paper discusses the security assessment problem of SDN-MNs and proposes a methodology using attack graphs and AHP. Secondly, to address the diversity and complexity of SDN-MNs, a novel attack graph definition and attack graph generation algorithm are proposed. In order to quantify security levels, the Node Minimal Effort (NME) is defined to quantify attack cost and derive system security levels based on NME. Thirdly, to calculate the NME of an attack graph that takes the dynamic factors of SDN-MN into consideration, we use AHP integrated with the Technique for Order Preference by Similarity to an Ideal Solution (TOPSIS) as the methodology. Finally, we offer a case study to validate the proposed methodology. The case study and evaluation show the advantages of the proposed security assessment mechanism. PMID:26694409

  10. A Security Assessment Mechanism for Software-Defined Networking-Based Mobile Networks.

    PubMed

    Luo, Shibo; Dong, Mianxiong; Ota, Kaoru; Wu, Jun; Li, Jianhua

    2015-01-01

    Software-Defined Networking-based Mobile Networks (SDN-MNs) are considered the future of 5G mobile network architecture. With the evolving cyber-attack threat, security assessments need to be performed in the network management. Due to the distinctive features of SDN-MNs, such as their dynamic nature and complexity, traditional network security assessment methodologies cannot be applied directly to SDN-MNs, and a novel security assessment methodology is needed. In this paper, an effective security assessment mechanism based on attack graphs and an Analytic Hierarchy Process (AHP) is proposed for SDN-MNs. Firstly, this paper discusses the security assessment problem of SDN-MNs and proposes a methodology using attack graphs and AHP. Secondly, to address the diversity and complexity of SDN-MNs, a novel attack graph definition and attack graph generation algorithm are proposed. In order to quantify security levels, the Node Minimal Effort (NME) is defined to quantify attack cost and derive system security levels based on NME. Thirdly, to calculate the NME of an attack graph that takes the dynamic factors of SDN-MN into consideration, we use AHP integrated with the Technique for Order Preference by Similarity to an Ideal Solution (TOPSIS) as the methodology. Finally, we offer a case study to validate the proposed methodology. The case study and evaluation show the advantages of the proposed security assessment mechanism. PMID:26694409

  11. Dynamic Network-Based Epistasis Analysis: Boolean Examples

    PubMed Central

    Azpeitia, Eugenio; Benítez, Mariana; Padilla-Longoria, Pablo; Espinosa-Soto, Carlos; Alvarez-Buylla, Elena R.

    2011-01-01

    In this article we focus on how the hierarchical and single-path assumptions of epistasis analysis can bias the inference of gene regulatory networks. Here we emphasize the critical importance of dynamic analyses, and specifically illustrate the use of Boolean network models. Epistasis in a broad sense refers to gene interactions, however, as originally proposed by Bateson, epistasis is defined as the blocking of a particular allelic effect due to the effect of another allele at a different locus (herein, classical epistasis). Classical epistasis analysis has proven powerful and useful, allowing researchers to infer and assign directionality to gene interactions. As larger data sets are becoming available, the analysis of classical epistasis is being complemented with computer science tools and system biology approaches. We show that when the hierarchical and single-path assumptions are not met in classical epistasis analysis, the access to relevant information and the correct inference of gene interaction topologies is hindered, and it becomes necessary to consider the temporal dynamics of gene interactions. The use of dynamical networks can overcome these limitations. We particularly focus on the use of Boolean networks that, like classical epistasis analysis, relies on logical formalisms, and hence can complement classical epistasis analysis and relax its assumptions. We develop a couple of theoretical examples and analyze them from a dynamic Boolean network model perspective. Boolean networks could help to guide additional experiments and discern among alternative regulatory schemes that would be impossible or difficult to infer without the elimination of these assumption from the classical epistasis analysis. We also use examples from the literature to show how a Boolean network-based approach has resolved ambiguities and guided epistasis analysis. Our article complements previous accounts, not only by focusing on the implications of the hierarchical and

  12. Wood Defect Identification Based on Artificial Neural Network

    NASA Astrophysics Data System (ADS)

    Zhu, Xiao-Dong; Cao, Jun; Wang, Feng-Hu; Sun, Jian-Ping; Liu, Yu

    Defects in wooden material reduce the value of timber. In order to save and improve the utilization of the timber, many studies are carried out on the ways to detect defects in wood. The recent development of computer technology, data processing technology and signal processing technology provides researchers with more damage identification problem solution ideas and methods. This article studies the vibration characteristics of wood. With an exploration of the wavelet analysis and artificial neural network for the wood composite material defects based on non-destructive testing, an artificial neural network model is established for wood-based composite materials non-destructive testing technology.

  13. Optimising base station location for UMTS cellular networks

    NASA Astrophysics Data System (ADS)

    Kalata, G.; Pozniak-Koszalka, I.; Koszalka, L.; Kasprzak, A.

    2014-12-01

    Rapid development of universal mobile telecommunication systems put demands on tools for assisting planning of cellular network infrastructure. The tools need to focus on critical issues in modern cellular networks and techniques used for previous generation system no longer serve useful. In this paper, an algorithm based on Branch & Bound approach is proposed for solving base station location problem, covering interference levels, traffic demands and power control mechanism. The efficiency of the algorithm is evaluated with respect to existing approaches for solving this problem - using the designed and implemented experimentation system.

  14. Operation of a DNA-Based Autocatalytic Network in Serum

    NASA Astrophysics Data System (ADS)

    Graugnard, Elton; Cox, Amber; Lee, Jeunghoon; Jorcyk, Cheryl; Yurke, Bernard; Hughes, William L.

    The potential for inferring the presence of cancer by the detection of miRNA in human blood has motivated research into the design and operation of DNA-based chemical amplifiers that can operate in bodily fluids. As a first step toward this goal, we have tested the operation of a DNA-based autocatalytic network in human serum and mouse serum. With the addition of sodium dodecyl sulfate to prevent degradation by nuclease activity, the network was found to operate successfully with both DNA and RNA catalysts.

  15. Parallel CFD design on network-based computer

    NASA Technical Reports Server (NTRS)

    Cheung, Samson

    1995-01-01

    Combining multiple engineering workstations into a network-based heterogeneous parallel computer allows application of aerodynamic optimization with advanced computational fluid dynamics codes, which can be computationally expensive on mainframe supercomputers. This paper introduces a nonlinear quasi-Newton optimizer designed for this network-based heterogeneous parallel computing environment utilizing a software called Parallel Virtual Machine. This paper will introduce the methodology behind coupling a Parabolized Navier-Stokes flow solver to the nonlinear optimizer. This parallel optimization package is applied to reduce the wave drag of a body of revolution and a wing/body configuration with results of 5% to 6% drag reduction.

  16. CFD Optimization on Network-Based Parallel Computer System

    NASA Technical Reports Server (NTRS)

    Cheung, Samson H.; Holst, Terry L. (Technical Monitor)

    1994-01-01

    Combining multiple engineering workstations into a network-based heterogeneous parallel computer allows application of aerodynamic optimization with advance computational fluid dynamics codes, which is computationally expensive in mainframe supercomputer. This paper introduces a nonlinear quasi-Newton optimizer designed for this network-based heterogeneous parallel computer on a software called Parallel Virtual Machine. This paper will introduce the methodology behind coupling a Parabolized Navier-Stokes flow solver to the nonlinear optimizer. This parallel optimization package has been applied to reduce the wave drag of a body of revolution and a wing/body configuration with results of 5% to 6% drag reduction.

  17. Network-based H∞ synchronization control of time-delay neural networks with communication constraints

    NASA Astrophysics Data System (ADS)

    Dong, Hui; Ling, Rongyao; Zhang, Dan

    2016-03-01

    This paper is concerned with the network-based H∞ synchronization control for a class of discrete time-delay neural networks, and attention is focused on how to reduce the communication rate since the communication resource is limited. Techniques such as the measurement size reduction, signal quantization and stochastic signal transmission are introduced to achieve the above goal. An uncertain switched system model is first proposed to capture the above-networked uncertainties. Based on the switched system theory and Lyapunov stability approach, a sufficient condition is obtained such that the closed-loop synchronization system is exponentially stable in the mean-square sense with a prescribed H∞ performance level. The controller gains are determined by solving a set of linear matrix inequalities (LMIs). A numerical example is finally presented to show the effectiveness of the proposed design method.

  18. A Network-Based Electrical Engineering Laboratory

    ERIC Educational Resources Information Center

    Asimopoulos, Nikolaos D.; Kyriakos, Nathanail; Mpatzakis, Vlasios

    2007-01-01

    Technical education is, by definition, a field that requires hands-on practice and experience by the student. When it comes to distant learning, technical education suffers from lack of such practical study, given the fact that e-learning is based on theoretical material being provided remotely to the student. This article presents the idea of…

  19. Cross-layer restoration with software defined networking based on IP over optical transport networks

    NASA Astrophysics Data System (ADS)

    Yang, Hui; Cheng, Lei; Deng, Junni; Zhao, Yongli; Zhang, Jie; Lee, Young

    2015-10-01

    The IP over optical transport network is a very promising networking architecture applied to the interconnection of geographically distributed data centers due to the performance guarantee of low delay, huge bandwidth and high reliability at a low cost. It can enable efficient resource utilization and support heterogeneous bandwidth demands in highly-available, cost-effective and energy-effective manner. In case of cross-layer link failure, to ensure a high-level quality of service (QoS) for user request after the failure becomes a research focus. In this paper, we propose a novel cross-layer restoration scheme for data center services with software defined networking based on IP over optical network. The cross-layer restoration scheme can enable joint optimization of IP network and optical network resources, and enhance the data center service restoration responsiveness to the dynamic end-to-end service demands. We quantitatively evaluate the feasibility and performances through the simulation under heavy traffic load scenario in terms of path blocking probability and path restoration latency. Numeric results show that the cross-layer restoration scheme improves the recovery success rate and minimizes the overall recovery time.

  20. Network-level accident-mapping: Distance based pattern matching using artificial neural network.

    PubMed

    Deka, Lipika; Quddus, Mohammed

    2014-04-01

    The objective of an accident-mapping algorithm is to snap traffic accidents onto the correct road segments. Assigning accidents onto the correct segments facilitate to robustly carry out some key analyses in accident research including the identification of accident hot-spots, network-level risk mapping and segment-level accident risk modelling. Existing risk mapping algorithms have some severe limitations: (i) they are not easily 'transferable' as the algorithms are specific to given accident datasets; (ii) they do not perform well in all road-network environments such as in areas of dense road network; and (iii) the methods used do not perform well in addressing inaccuracies inherent in and type of road environment. The purpose of this paper is to develop a new accident mapping algorithm based on the common variables observed in most accident databases (e.g. road name and type, direction of vehicle movement before the accident and recorded accident location). The challenges here are to: (i) develop a method that takes into account uncertainties inherent to the recorded traffic accident data and the underlying digital road network data, (ii) accurately determine the type and proportion of inaccuracies, and (iii) develop a robust algorithm that can be adapted for any accident set and road network of varying complexity. In order to overcome these challenges, a distance based pattern-matching approach is used to identify the correct road segment. This is based on vectors containing feature values that are common in the accident data and the network data. Since each feature does not contribute equally towards the identification of the correct road segments, an ANN approach using the single-layer perceptron is used to assist in "learning" the relative importance of each feature in the distance calculation and hence the correct link identification. The performance of the developed algorithm was evaluated based on a reference accident dataset from the UK confirming that

  1. Network Science Based Quantification of Resilience Demonstrated on the Indian Railways Network

    PubMed Central

    Bhatia, Udit; Kumar, Devashish; Kodra, Evan; Ganguly, Auroop R.

    2015-01-01

    The structure, interdependence, and fragility of systems ranging from power-grids and transportation to ecology, climate, biology and even human communities and the Internet have been examined through network science. While response to perturbations has been quantified, recovery strategies for perturbed networks have usually been either discussed conceptually or through anecdotal case studies. Here we develop a network science based quantitative framework for measuring, comparing and interpreting hazard responses as well as recovery strategies. The framework, motivated by the recently proposed temporal resilience paradigm, is demonstrated with the Indian Railways Network. Simulations inspired by the 2004 Indian Ocean Tsunami and the 2012 North Indian blackout as well as a cyber-physical attack scenario illustrate hazard responses and effectiveness of proposed recovery strategies. Multiple metrics are used to generate various recovery strategies, which are simply sequences in which system components should be recovered after a disruption. Quantitative evaluation of these strategies suggests that faster and more efficient recovery is possible through network centrality measures. Optimal recovery strategies may be different per hazard, per community within a network, and for different measures of partial recovery. In addition, topological characterization provides a means for interpreting the comparative performance of proposed recovery strategies. The methods can be directly extended to other Large-Scale Critical Lifeline Infrastructure Networks including transportation, water, energy and communications systems that are threatened by natural or human-induced hazards, including cascading failures. Furthermore, the quantitative framework developed here can generalize across natural, engineered and human systems, offering an actionable and generalizable approach for emergency management in particular as well as for network resilience in general. PMID:26536227

  2. Network Science Based Quantification of Resilience Demonstrated on the Indian Railways Network.

    PubMed

    Bhatia, Udit; Kumar, Devashish; Kodra, Evan; Ganguly, Auroop R

    2015-01-01

    The structure, interdependence, and fragility of systems ranging from power-grids and transportation to ecology, climate, biology and even human communities and the Internet have been examined through network science. While response to perturbations has been quantified, recovery strategies for perturbed networks have usually been either discussed conceptually or through anecdotal case studies. Here we develop a network science based quantitative framework for measuring, comparing and interpreting hazard responses as well as recovery strategies. The framework, motivated by the recently proposed temporal resilience paradigm, is demonstrated with the Indian Railways Network. Simulations inspired by the 2004 Indian Ocean Tsunami and the 2012 North Indian blackout as well as a cyber-physical attack scenario illustrate hazard responses and effectiveness of proposed recovery strategies. Multiple metrics are used to generate various recovery strategies, which are simply sequences in which system components should be recovered after a disruption. Quantitative evaluation of these strategies suggests that faster and more efficient recovery is possible through network centrality measures. Optimal recovery strategies may be different per hazard, per community within a network, and for different measures of partial recovery. In addition, topological characterization provides a means for interpreting the comparative performance of proposed recovery strategies. The methods can be directly extended to other Large-Scale Critical Lifeline Infrastructure Networks including transportation, water, energy and communications systems that are threatened by natural or human-induced hazards, including cascading failures. Furthermore, the quantitative framework developed here can generalize across natural, engineered and human systems, offering an actionable and generalizable approach for emergency management in particular as well as for network resilience in general. PMID:26536227

  3. Structure-Based Design of a Protein Immunogen that Displays an HIV-1 gp41 Neutralizing Epitope

    SciTech Connect

    Stanfield, Robyn L.; Julien, Jean-Philippe; Pejchal, Robert; Gach, Johannes S.; Zwick, Michael B.; Wilson, Ian A.

    2012-06-27

    Antibody Z13e1 is a relatively broadly neutralizing anti-human immunodeficiency virus type 1 antibody that recognizes the membrane-proximal external region (MPER) of the human immunodeficiency virus type 1 envelope glycoprotein gp41. Based on the crystal structure of an MPER epitope peptide in complex with Z13e1 Fab, we identified an unrelated protein, interleukin (IL)-22, with a surface-exposed region that is structurally homologous in its backbone to the gp41 Z13e1 epitope. By grafting the gp41 Z13e1 epitope sequence onto the structurally homologous region in IL-22, we engineered a novel protein (Z13-IL22-2) that contains the MPER epitope sequence for use as a potential immunogen and as a reagent for the detection of Z13e1-like antibodies. The Z13-IL22-2 protein binds Fab Z13e1 with a K{sub d} of 73 nM. The crystal structure of Z13-IL22-2 in complex with Fab Z13e1 shows that the epitope region is faithfully replicated in the Fab-bound scaffold protein; however, isothermal calorimetry studies indicate that Fab binding to Z13-IL22-2 is not a lock-and-key event, leaving open the question of whether conformational changes upon binding occur in the Fab, in Z13-IL-22, or in both.

  4. A potential therapeutic peptide-based neutralizer that potently inhibits Shiga toxin 2 in vitro and in vivo

    PubMed Central

    Li, Tao; Tu, Wei; Liu, Yuenan; Zhou, Peng; Cai, Kun; Li, Zhan; Liu, Xiong; Ning, Nianzhi; Huang, Jie; Wang, Shenghan; Huang, Jian; Wang, Hui

    2016-01-01

    Shiga toxin 2 (Stx2) is a major virulence factor in infections with Stx-producing Escherichia coli (STEC), which can cause serious clinical complications in humans, such as hemolytic uremic syndrome (HUS). Recently, we screened and identified two peptide-based Stx2 neutralizers, TF-1 and WA-8, which specifically and directly bind to Stx2. Computer simulations suggested that the majority of TF-1 or WA-8 binds tightly at the receptor-binding site 3 of Stx2. The two peptides also effectively inhibited the cytotoxic activity of Stx2 by blocking the binding of Stx2 to target cells. TF-1 exhibits remarkable therapeutic potency in both mice and rat toxicity models. In mice toxicity models, TF-1 provided full protection when mice were injected with 5 LD50 of Stx2. In rat toxicity models, TF-1 reduced fatal tissue damage and completely protected rats from the lethal challenges of Stx2. In these rats, TF-1 significantly decreased the concentration of Stx2 in blood and diminished tissue distribution levels of Stx2. Furthermore, TF-1 effectively protected rats from the pathological effects caused by Stx2, especially in the kidney, thymus, adrenal gland, and lung. Taken together, these results indicate that TF-1 is a promising therapeutic agent against the pathogenicity of Stx2. PMID:26903273

  5. Application of a Java-based, univel geometry, neutral particle Monte Carlo code to the searchlight problem

    SciTech Connect

    Charles A. Wemple; Joshua J. Cogliati

    2005-04-01

    A univel geometry, neutral particle Monte Carlo transport code, written entirely in the Java programming language, is under development for medical radiotherapy applications. The code uses ENDF-VI based continuous energy cross section data in a flexible XML format. Full neutron-photon coupling, including detailed photon production and photonuclear reactions, is included. Charged particle equilibrium is assumed within the patient model so that detailed transport of electrons produced by photon interactions may be neglected. External beam and internal distributed source descriptions for mixed neutron-photon sources are allowed. Flux and dose tallies are performed on a univel basis. A four-tap, shift-register-sequence random number generator is used. Initial verification and validation testing of the basic neutron transport routines is underway. The searchlight problem was chosen as a suitable first application because of the simplicity of the physical model. Results show excellent agreement with analytic solutions. Computation times for similar numbers of histories are comparable to other neutron MC codes written in C and FORTRAN.

  6. A potential therapeutic peptide-based neutralizer that potently inhibits Shiga toxin 2 in vitro and in vivo.

    PubMed

    Li, Tao; Tu, Wei; Liu, Yuenan; Zhou, Peng; Cai, Kun; Li, Zhan; Liu, Xiong; Ning, Nianzhi; Huang, Jie; Wang, Shenghan; Huang, Jian; Wang, Hui

    2016-01-01

    Shiga toxin 2 (Stx2) is a major virulence factor in infections with Stx-producing Escherichia coli (STEC), which can cause serious clinical complications in humans, such as hemolytic uremic syndrome (HUS). Recently, we screened and identified two peptide-based Stx2 neutralizers, TF-1 and WA-8, which specifically and directly bind to Stx2. Computer simulations suggested that the majority of TF-1 or WA-8 binds tightly at the receptor-binding site 3 of Stx2. The two peptides also effectively inhibited the cytotoxic activity of Stx2 by blocking the binding of Stx2 to target cells. TF-1 exhibits remarkable therapeutic potency in both mice and rat toxicity models. In mice toxicity models, TF-1 provided full protection when mice were injected with 5 LD50 of Stx2. In rat toxicity models, TF-1 reduced fatal tissue damage and completely protected rats from the lethal challenges of Stx2. In these rats, TF-1 significantly decreased the concentration of Stx2 in blood and diminished tissue distribution levels of Stx2. Furthermore, TF-1 effectively protected rats from the pathological effects caused by Stx2, especially in the kidney, thymus, adrenal gland, and lung. Taken together, these results indicate that TF-1 is a promising therapeutic agent against the pathogenicity of Stx2. PMID:26903273

  7. A Serum Neutralization Test for Infectious Bovine Rhinotracheitis Based on Colour Reaction and Cytopathic effects in Cell Culture

    PubMed Central

    Greig, A. S.

    1969-01-01

    A serum neutralization (SN) test based on a combination of indicator colour change in medium and cytopathic (CP) effect in cells has been devised for the detection of infectious bovine rhinotracheitis antibodies. Serum dilutions of 1:6, 1:18 and 1:54 are made in a medium containing phenol red and are mixed in equal quantities with a suspension of virus containing 100 cell culture infectious doses (CCID50) per volume of mixture. The serum-virus mixtures are held in small glass tubes and are covered with a layer of mineral oil. Following a two hour period of incubation at 37°C a quantity of bovine fetal kidney cells is added to each tube to detect the presence of unneutralized virus. After four to six days incubation the results of the SN test may be read by microscopic examination for CP effect by means of an inverted microscope, or by observing the colour of the phenol red. PMID:4305762

  8. High-ion temperature experiments with negative-ion-based neutral beam injection heating in Large Helical Device

    NASA Astrophysics Data System (ADS)

    Takeiri, Y.; Morita, S.; Tsumori, K.; Ikeda, K.; Oka, Y.; Osakabe, M.; Nagaoka, K.; Goto, M.; Miyazawa, J.; Masuzaki, S.; Ashikawa, N.; Yokoyama, M.; Murakami, S.; Narihara, K.; Yamada, I.; Kubo, S.; Shimozuma, T.; Inagaki, S.; Tanaka, K.; Peterson, B. J.; Ida, K.; Kaneko, O.; Komori, A.; LHD Experimental Group

    2005-07-01

    High-Z plasmas have been produced with Ar and/or Ne gas fuelling to increase the ion temperature in Large Helical Device (LHD) plasmas heated with high-energy negative-ion-based neutral beam injection (NBI). Although the electron heating is dominant in the high-energy NBI heating, the direct ion heating power is significantly enhanced in low-density plasmas due to both an increase in the beam absorption (ionization) power and a reduction of the ion density in the high-Z plasmas. Intensive neon- and/or argon-glow discharge cleaning works well to suppress dilution of the high-Z plasmas with wall-absorbed hydrogen. As a result, the ion temperature increases with an increase in the ion heating power normalized by the ion density and reaches 10 keV. An increase in the ion temperature is also observed with the addition of centrally focused electron cyclotron resonance heating to a low-density and high-Z NBI plasma, suggesting improvement of the ion transport. The results obtained in the high-Z plasma experiments with high-energy NBI heating suggest that an increase in the direct ion heating power and improvement of the ion transport are essential to ion temperature rise, and that a high-ion temperature could be obtained as well in hydrogen plasmas with low-energy positive-NBI heating which is planned in the near future in the LHD.

  9. Absolute frequency measurement of the neutral 40Ca optical frequency standard at 657 nm based on microkelvin atoms

    NASA Astrophysics Data System (ADS)

    Wilpers, G.; Oates, C. W.; Diddams, S. A.; Bartels, A.; Fortier, T. M.; Oskay, W. H.; Bergquist, J. C.; Jefferts, S. R.; Heavner, T. P.; Parker, T. E.; Hollberg, L.

    2007-04-01

    We report an absolute frequency measurement of the optical clock transition at 657 nm in 40Ca with a relative uncertainty of 7.5 × 10-15, one of the most accurate frequency measurements of a neutral atom optical transition to date. The frequency (455 986 240 494 135.8 ± 3.4) Hz was measured by stabilizing a diode laser system to a spectroscopic signal derived from an ensemble of 106 atoms cooled in two stages to a temperature of 10 µK. The measurement used a femtosecond-laser-based frequency comb to compare the Ca transition frequency with that of the single-ion 199Hg+ optical frequency standard at NIST. The Hg+ frequency was simultaneously calibrated relative to the NIST Cs fountain via the NIST time scale to yield an absolute value for the Ca transition frequency. The relative fractional instability between the two optical standards was 2 × 10-15 for 10 s of averaging time and 2 × 10-16 for 2000 s.

  10. Generation of Neutralizing Monoclonal Antibodies against a Conformational Epitope of Human Adenovirus Type 7 (HAdv-7) Incorporated in Capsid Encoded in a HAdv-3-Based Vector

    PubMed Central

    Li, Xiao; Zhou, Zhichao; Li, Chenyang; Zhou, Rong

    2014-01-01

    The generation of monoclonal antibodies (MAbs) by epitope-based immunization is difficult because the immunogenicity of simple peptides is poor and T cells must be potently stimulated and immunological memory elicited. A strategy in which antigen is incorporated into the adenoviral capsid protein has been used previously to develop antibody responses against several vaccine targets and may offer a solution to this problem. In this study, we used a similar strategy to develop HAdv-7-neutralizing MAbs using rAdMHE3 virions into which hexon hypervariable region 5 (HVR5) of adenovirus type 7 (HAdv-7) was incorporated. The epitope mutant rAdMHE3 was generated by replacing HVR5 of Ad3EGFP, a recombinant HAdv-3-based vector expressing enhanced green fluorescence protein, with HVR5 of HAdv-7. We immunized BALB/c mice with rAdMHE3 virions and produced 22 different MAbs against them, four of which showed neutralizing activity against HAdv-7 in vitro. Using an indirect enzyme-linked immunosorbent assay (ELISA) analysis and an antibody-binding-competition ELISA with Ad3EGFP, HAdv-7, and a series of chimeric adenoviral particles containing epitope mutants, we demonstrated that the four MAbs recognize the neutralization site within HVR5 of the HAdv-7 virion. Using an immunoblotting analysis and ELISA with HAdv-7, recombinant peptides, and a synthetic peptide, we also showed that the neutralizing epitope within HVR5 of the HAdv-7 virion is a conformational epitope. These findings suggest that it is feasible to use a strategy in which antigen is incorporated into the adenoviral capsid protein to generate neutralizing MAbs. This strategy may also be useful for developing therapeutic neutralizing MAbs and designing recombinant vector vaccines against HAdv-7, and in structural analysis of adenoviruses. PMID:25054273

  11. Design principles for clinical network-based proteomics.

    PubMed

    Goh, Wilson Wen Bin; Wong, Limsoon

    2016-07-01

    Integrating biological networks with proteomics is a tantalizing option for system-level analysis; for example it can help remove false-positives from proteomics data and improve coverage by detecting false-negatives, as well as resolving inconsistent inter-sample protein expression due to biological heterogeneity. Yet, designing a robust network-based analysis strategy on proteomics data is nontrivial. The issues include dealing with test set bias caused by, for example, inappropriate normalization procedure, devising appropriate benchmarking criteria and formulating statistically robust feature-selection techniques. Given the increasing importance of proteomics in contemporary clinical studies, more powerful network-based approaches are needed. We provide some design principles and considerations that can help achieve this, while taking into account the idiosyncrasies of proteomics data. PMID:27240775

  12. Coverage in Wireless Sensor Network Based on Probabilistic Sensing Model

    NASA Astrophysics Data System (ADS)

    Li, Fen; Deng, Kai; Meng, Fanzhi; Weiyan, Zhang

    One of the major problem to consider in designing wireless sensor network is how to extend the network lifetime and provide desired quality of service. To achieve this, a broadly-used method is topology control. This paper studies the problem of how to ensure the network fully connected without nodes' location information. The coverage control model based on probabilistic sensing model is proposed in this paper. With random sensor deployment, the sensing node and communicating node number can be calculated based on the size of sensing region and the performance parameters of node (e.g., node sensing radius, communication radius, and so on). Simulation results show that the actual coverage quality provided by sensing nodes scheduled with the proposed coverage control model is higher than the threshold of coverage quality.

  13. Network-based in silico drug efficacy screening

    PubMed Central

    Guney, Emre; Menche, Jörg; Vidal, Marc; Barábasi, Albert-László

    2016-01-01

    The increasing cost of drug development together with a significant drop in the number of new drug approvals raises the need for innovative approaches for target identification and efficacy prediction. Here, we take advantage of our increasing understanding of the network-based origins of diseases to introduce a drug-disease proximity measure that quantifies the interplay between drugs targets and diseases. By correcting for the known biases of the interactome, proximity helps us uncover the therapeutic effect of drugs, as well as to distinguish palliative from effective treatments. Our analysis of 238 drugs used in 78 diseases indicates that the therapeutic effect of drugs is localized in a small network neighborhood of the disease genes and highlights efficacy issues for drugs used in Parkinson and several inflammatory disorders. Finally, network-based proximity allows us to predict novel drug-disease associations that offer unprecedented opportunities for drug repurposing and the detection of adverse effects. PMID:26831545

  14. Hand posture recognizer based on separator wavelet networks

    NASA Astrophysics Data System (ADS)

    Bouchrika, Tahani; Jemai, Olfa; Zaied, Mourad; Ben Amar, Chokri

    2015-12-01

    This paper presents a novel hand posture recognizer based on separator wavelet networks (SWNs). Aiming at creating a robust and rapid hand posture recognizer, we have contributed by proposing a new training algorithm for the wavelet network classifier based on fast wavelet transform (FWN). So, the contribution resides in reducing the number of WNs modeling training data. To make that, inspiring from the adaboost feature selection method, we thought to create SWNs (n-1 WNs for n classes) instead of modeling each training sample by its wavelet network (WN). By proposing the new training algorithm, the recognition phase will be positively influenced. It will be more rapid thanks to the reduction of the number of comparisons between test images WNs and training WNs. Comparisons with other works, employing universal hand posture datasets are presented and discussed. Obtained results have shown that the new hand posture recognizer is comparable to previously established ones.

  15. Networks in financial markets based on the mutual information rate

    NASA Astrophysics Data System (ADS)

    Fiedor, Paweł

    2014-05-01

    In the last few years there have been many efforts in econophysics studying how network theory can facilitate understanding of complex financial markets. These efforts consist mainly of the study of correlation-based hierarchical networks. This is somewhat surprising as the underlying assumptions of research looking at financial markets are that they are complex systems and thus behave in a nonlinear manner, which is confirmed by numerous studies, making the use of correlations which are inherently dealing with linear dependencies only baffling. In this paper we introduce a way to incorporate nonlinear dynamics and dependencies into hierarchical networks to study financial markets using mutual information and its dynamical extension: the mutual information rate. We show that this approach leads to different results than the correlation-based approach used in most studies, on the basis of 91 companies listed on the New York Stock Exchange 100 between 2003 and 2013, using minimal spanning trees and planar maximally filtered graphs.

  16. Design and Application of Nanogel-Based Polymer Networks

    NASA Astrophysics Data System (ADS)

    Dailing, Eric Alan

    Crosslinked polymer networks have wide application in biomaterials, from soft hydrogel scaffolds for cell culture and tissue engineering to glassy, high modulus dental restoratives. Composite materials formed with nanogels as a means for tuning network structure on the nanoscale have been reported, but no investigation into nanogels as the primary network component has been explored to this point. This thesis was dedicated to studying network formation from the direct polymerization of nanogels and investigating applications for these unique materials. Covalently crosslinked polymer networks were synthesized from polymerizable nanogels without the use of reactive small monomers or oligomers. Network properties were controlled by the chemical and physical properties of the nanogel, allowing for materials to be designed from nanostructured macromolecular precursors. Nanogels were synthesized from a thermally initiated solution free radical polymerization of a monomethacrylate, a dimethacrylate, and a thiol-based chain transfer agent. Monomers with a range of hydrophilic and hydrophobic character were copolymerized, and polymerizable groups were introduced through an alcohol-isocyanate click reaction. Nanogels were dispersible in water up to 75 wt%, including nanogels that contained a relatively high fraction of a conventionally water-insoluble component. Nanogels with molecular weights that ranged from 10's to 100's of kDa and hydrodynamic radii between 4 and 10 nm were obtained. Macroscopic crosslinked polymer networks were synthesized from the photopolymerization of methacrylate-functionalized nanogels in inert solvent, which was typically water. The nanogel composition and internal branching density affected both covalent and non-covalent interparticle interactions, which dictated the final mechanical properties of the networks. Nanogels with progressively disparate hydrophilic and hydrophobic character were synthesized to explore the potential for creating

  17. An Arabidopsis gene network based on the graphical Gaussian model

    PubMed Central

    Ma, Shisong; Gong, Qingqiu; Bohnert, Hans J.

    2007-01-01

    We describe a gene network for the Arabidopsis thaliana transcriptome based on a modified graphical Gaussian model (GGM). Through partial correlation (pcor), GGM infers coregulation patterns between gene pairs conditional on the behavior of other genes. Regularized GGM calculated pcor between gene pairs among ∼2000 input genes at a time. Regularized GGM coupled with iterative random samplings of genes was expanded into a network that covered the Arabidopsis genome (22,266 genes). This resulted in a network of 18,625 interactions (edges) among 6760 genes (nodes) with high confidence and connections representing ∼0.01% of all possible edges. When queried for selected genes, locally coherent subnetworks mainly related to metabolic functions, and stress responses emerged. Examples of networks for biochemical pathways, cell wall metabolism, and cold responses are presented. GGM displayed known coregulation pathways as subnetworks and added novel components to known edges. Finally, the network reconciled individual subnetworks in a topology joined at the whole-genome level and provided a general framework that can instruct future studies on plant metabolism and stress responses. The network model is included. PMID:17921353

  18. Optimal network topology for structural robustness based on natural connectivity

    NASA Astrophysics Data System (ADS)

    Peng, Guan-sheng; Wu, Jun

    2016-02-01

    The structural robustness of the infrastructure of various real-life systems, which can be represented by networks, is of great importance. Thus we have proposed a tabu search algorithm to optimize the structural robustness of a given network by rewiring the links and fixing the node degrees. The objective of our algorithm is to maximize a new structural robustness measure, natural connectivity, which provides a sensitive and reliable measure of the structural robustness of complex networks and has lower computation complexity. We initially applied this method to several networks with different degree distributions for contrast analysis and investigated the basic properties of the optimal network. We discovered that the optimal network based on the power-law degree distribution exhibits a roughly "eggplant-like" topology, where there is a cluster of high-degree nodes at the head and other low-degree nodes scattered across the body of "eggplant". Additionally, the cost to rewire links in practical applications is considered; therefore, we optimized this method by employing the assortative rewiring strategy and validated its efficiency.

  19. Social network analysis based on WWW search engine

    NASA Astrophysics Data System (ADS)

    Lee, Sang Hoon; Kim, Pan-Jun; Ahn, Yong-Yeol; Jeong, Hawoong

    2007-03-01

    Recently, massive digital records have made it possible to analyze a huge amount of data in social sciences, one of which is social network theory. We investigate social networks between people by extracting information on the World Wide Web. Using famous search engines such as Google, we construct weighted social networks where the nodes are the names of people and the weight of each link is assigned as the number of web pages including both of the names attached to the link. The weight distribution is found to be quite broad with the heavy-tail. The strength of a node, defined as the sum of weights over the node, is strongly correlated with the number of web pages including the single node. We compare networks constructed by this method with real networks to test the reliability of the method. Furthermore, we suggest the quantity, called the effective degree, characterizing the homogeneity (or heterogeneity) of weight distribution for each node in the weighted network. Another way to quantify the importance of each node, based on the effective degree, is also introduced.

  20. Scene understanding based on network-symbolic models

    NASA Astrophysics Data System (ADS)

    Kuvich, Gary

    2005-05-01

    New generations of smart weapons and unmanned vehicles must have reliable perceptual systems that are similar to human vision. Instead of precise computations of 3-dimensional models, a network-symbolic system converts image information into an "understandable" Network-Symbolic format, which is similar to relational knowledge models. Logic of visual scenes can be captured in the Network-Symbolic models and used for the disambiguation of visual information. It is hard to use geometric operations for processing of natural images. Instead, the brain builds a relational network-symbolic structure of visual scene, using different clues to set up the relational order of surfaces and objects. Feature, symbol, and predicate are equivalent in the biologically inspired Network-Symbolic systems. A linking mechanism binds these features/symbols into coherent structures, and image converts from a "raster" into a "vector" representation that can be better interpreted by higher-level knowledge structures. View-based object recognition is a hard problem for traditional algorithms that directly match a primary view of an object to a model. In Network-Symbolic Models, the derived structure, not the primary view, is a subject for recognition. Such recognition is not affected by local changes and appearances of the object as seen from a set of similar views.

  1. Adaptive Neural Network Based Control of Noncanonical Nonlinear Systems.

    PubMed

    Zhang, Yanjun; Tao, Gang; Chen, Mou

    2016-09-01

    This paper presents a new study on the adaptive neural network-based control of a class of noncanonical nonlinear systems with large parametric uncertainties. Unlike commonly studied canonical form nonlinear systems whose neural network approximation system models have explicit relative degree structures, which can directly be used to derive parameterized controllers for adaptation, noncanonical form nonlinear systems usually do not have explicit relative degrees, and thus their approximation system models are also in noncanonical forms. It is well-known that the adaptive control of noncanonical form nonlinear systems involves the parameterization of system dynamics. As demonstrated in this paper, it is also the case for noncanonical neural network approximation system models. Effective control of such systems is an open research problem, especially in the presence of uncertain parameters. This paper shows that it is necessary to reparameterize such neural network system models for adaptive control design, and that such reparameterization can be realized using a relative degree formulation, a concept yet to be studied for general neural network system models. This paper then derives the parameterized controllers that guarantee closed-loop stability and asymptotic output tracking for noncanonical form neural network system models. An illustrative example is presented with the simulation results to demonstrate the control design procedure, and to verify the effectiveness of such a new design method. PMID:26285223

  2. Inferring Single Neuron Properties in Conductance Based Balanced Networks

    PubMed Central

    Pool, Román Rossi; Mato, Germán

    2011-01-01

    Balanced states in large networks are a usual hypothesis for explaining the variability of neural activity in cortical systems. In this regime the statistics of the inputs is characterized by static and dynamic fluctuations. The dynamic fluctuations have a Gaussian distribution. Such statistics allows to use reverse correlation methods, by recording synaptic inputs and the spike trains of ongoing spontaneous activity without any additional input. By using this method, properties of the single neuron dynamics that are masked by the balanced state can be quantified. To show the feasibility of this approach we apply it to large networks of conductance based neurons. The networks are classified as Type I or Type II according to the bifurcations which neurons of the different populations undergo near the firing onset. We also analyze mixed networks, in which each population has a mixture of different neuronal types. We determine under which conditions the intrinsic noise generated by the network can be used to apply reverse correlation methods. We find that under realistic conditions we can ascertain with low error the types of neurons present in the network. We also find that data from neurons with similar firing rates can be combined to perform covariance analysis. We compare the results of these methods (that do not requite any external input) to the standard procedure (that requires the injection of Gaussian noise into a single neuron). We find a good agreement between the two procedures. PMID:22016730

  3. [Forensic evidence-based medicine in computer communication networks].

    PubMed

    Qiu, Yun-Liang; Peng, Ming-Qi

    2013-12-01

    As an important component of judicial expertise, forensic science is broad and highly specialized. With development of network technology, increasement of information resources, and improvement of people's legal consciousness, forensic scientists encounter many new problems, and have been required to meet higher evidentiary standards in litigation. In view of this, evidence-based concept should be established in forensic medicine. We should find the most suitable method in forensic science field and other related area to solve specific problems in the evidence-based mode. Evidence-based practice can solve the problems in legal medical field, and it will play a great role in promoting the progress and development of forensic science. This article reviews the basic theory of evidence-based medicine and its effect, way, method, and evaluation in the forensic medicine in order to discuss the application value of forensic evidence-based medicine in computer communication networks. PMID:24665620

  4. Microfluidics based phantoms of superficial vascular network

    PubMed Central

    Luu, Long; Roman, Patrick A.; Mathews, Scott A.; Ramella-Roman, Jessica C.

    2012-01-01

    Several new bio-photonic techniques aim to measure flow in the human vasculature non-destructively. Some of these tools, such as laser speckle imaging or Doppler optical coherence tomography, are now reaching the clinical stage. Therefore appropriate calibration and validation techniques dedicated to these particular measurements are therefore of paramount importance. In this paper we introduce a fast prototyping technique based on laser micromachining for the fabrication of dynamic flow phantoms. Micro-channels smaller than 20 µm in width can be formed in a variety of materials such as epoxies, plastics, and household tape. Vasculature geometries can be easily and quickly modified to accommodate a particular experimental scenario. PMID:22741081

  5. Modeling DNA sequence-based cis-regulatory gene networks.

    PubMed

    Bolouri, Hamid; Davidson, Eric H

    2002-06-01

    Gene network analysis requires computationally based models which represent the functional architecture of regulatory interactions, and which provide directly testable predictions. The type of model that is useful is constrained by the particular features of developmentally active cis-regulatory systems. These systems function by processing diverse regulatory inputs, generating novel regulatory outputs. A computational model which explicitly accommodates this basic concept was developed earlier for the cis-regulatory system of the endo16 gene of the sea urchin. This model represents the genetically mandated logic functions that the system executes, but also shows how time-varying kinetic inputs are processed in different circumstances into particular kinetic outputs. The same basic design features can be utilized to construct models that connect the large number of cis-regulatory elements constituting developmental gene networks. The ultimate aim of the network models discussed here is to represent the regulatory relationships among the genomic control systems of the genes in the network, and to state their functional meaning. The target site sequences of the cis-regulatory elements of these genes constitute the physical basis of the network architecture. Useful models for developmental regulatory networks must represent the genetic logic by which the system operates, but must also be capable of explaining the real time dynamics of cis-regulatory response as kinetic input and output data become available. Most importantly, however, such models must display in a direct and transparent manner fundamental network design features such as intra- and intercellular feedback circuitry; the sources of parallel inputs into each cis-regulatory element; gene battery organization; and use of repressive spatial inputs in specification and boundary formation. Successful network models lead to direct tests of key architectural features by targeted cis-regulatory analysis. PMID

  6. Microseismic network design assessment based on 3D ray tracing

    NASA Astrophysics Data System (ADS)

    Näsholm, Sven Peter; Wuestefeld, Andreas; Lubrano-Lavadera, Paul; Lang, Dominik; Kaschwich, Tina; Oye, Volker

    2016-04-01

    There is increasing demand on the versatility of microseismic monitoring networks. In early projects, being able to locate any triggers was considered a success. These early successes led to a better understanding of how to extract value from microseismic results. Today operators, regulators, and service providers work closely together in order to find the optimum network design to meet various requirements. In the current study we demonstrate an integrated and streamlined network capability assessment approach. It is intended for use during the microseismic network design process prior to installation. The assessments are derived from 3D ray tracing between a grid of event points and the sensors. Three aspects are discussed: 1) Magnitude of completeness or detection limit; 2) Event location accuracy; and 3) Ground-motion hazard. The network capability parameters 1) and 2) are estimated at all hypothetic event locations and are presented in the form of maps given a seismic sensor coordinate scenario. In addition, the ray tracing traveltimes permit to estimate the point-spread-functions (PSFs) at the event grid points. PSFs are useful in assessing the resolution and focusing capability of the network for stacking-based event location and imaging methods. We estimate the performance for a hypothetical network case with 11 sensors. We consider the well-documented region around the San Andreas Fault Observatory at Depth (SAFOD) located north of Parkfield, California. The ray tracing is done through a detailed velocity model which covers a 26.2 by 21.2 km wide area around the SAFOD drill site with a resolution of 200 m both for the P-and S-wave velocities. Systematic network capability assessment for different sensor site scenarios prior to installation facilitates finding a final design which meets the survey objectives.

  7. Robustness in clustering-based weighted inter-connected networks

    NASA Astrophysics Data System (ADS)

    Qiu, Yuzhuo; Yağan, Osman

    2014-04-01

    We study the robustness of symmetrically coupled and clustering-based weighted heterogeneous inter-connected networks with respect to load-failure-induced cascades. This is done under the assumption that the flow dynamics are governed by global redistribution of loads based on weighted betweenness centrality. Our results indicate that no weighting bias should be assigned to inter-links when calculating shortest path between node pairs under the clustering-based weighting scheme; i.e., inter-links shall be treated no differently than intra-links. In contrast with local load redistribution cases, we show that increasing connectivity is preferred for the robustness against global load redistribution-based cascading failures in clustering-based weighted inter-connected networks. Furthermore, comparisons among weighting schemes reveal that, both the clustering-based and degree-based schemes outperform the random one in the sense of requiring lower initial and total investments required to ensure robustness. We also find that clustering-based scheme outperforms degree-based one in terms of requiring lower initial investments. Except in a limited range where weighting is heavily suppressed, clustering-based scheme is shown to outperform degree-based one in terms of total investments. Finally, when there exists a hard investment budget constraint, clustering-based weighting scheme would be a better choice against a two-nodes-induced failure than the degree-based weighting, and the clustering-based scheme is more stable than degree-based scheme against one-or-two-nodes-induced failure. We expect our findings to be significantly useful in designing real-world weighted inter-connected networks that are robust against load-failure-induced cascades.

  8. FIPA agent based network distributed control system

    SciTech Connect

    D. Abbott; V. Gyurjyan; G. Heyes; E. Jastrzembski; C. Timmer; E. Wolin

    2003-03-01

    A control system with the capabilities to combine heterogeneous control systems or processes into a uniform homogeneous environment is discussed. This dynamically extensible system is an example of the software system at the agent level of abstraction. This level of abstraction considers agents as atomic entities that communicate to implement the functionality of the control system. Agents' engineering aspects are addressed by adopting the domain independent software standard, formulated by FIPA. Jade core Java classes are used as a FIPA specification implementation. A special, lightweight, XML RDFS based, control oriented, ontology markup language is developed to standardize the description of the arbitrary control system data processor. Control processes, described in this language, are integrated into the global system at runtime, without actual programming. Fault tolerance and recovery issues are also addressed.

  9. Identifying node role in social network based on multiple indicators.

    PubMed

    Huang, Shaobin; Lv, Tianyang; Zhang, Xizhe; Yang, Yange; Zheng, Weimin; Wen, Chao

    2014-01-01

    It is a classic topic of social network analysis to evaluate the importance of nodes and identify the node that takes on the role of core or bridge in a network. Because a single indicator is not sufficient to analyze multiple characteristics of a node, it is a natural solution to apply multiple indicators that should be selected carefully. An intuitive idea is to select some indicators with weak correlations to efficiently assess different characteristics of a node. However, this paper shows that it is much better to select the indicators with strong correlations. Because indicator correlation is based on the statistical analysis of a large number of nodes, the particularity of an important node will be outlined if its indicator relationship doesn't comply with the statistical correlation. Therefore, the paper selects the multiple indicators including degree, ego-betweenness centrality and eigenvector centrality to evaluate the importance and the role of a node. The importance of a node is equal to the normalized sum of its three indicators. A candidate for core or bridge is selected from the great degree nodes or the nodes with great ego-betweenness centrality respectively. Then, the role of a candidate is determined according to the difference between its indicators' relationship with the statistical correlation of the overall network. Based on 18 real networks and 3 kinds of model networks, the experimental results show that the proposed methods perform quite well in evaluating the importance of nodes and in identifying the node role. PMID:25089823

  10. Novel indexes based on network structure to indicate financial market

    NASA Astrophysics Data System (ADS)

    Zhong, Tao; Peng, Qinke; Wang, Xiao; Zhang, Jing

    2016-02-01

    There have been various achievements to understand and to analyze the financial market by complex network model. However, current studies analyze the financial network model but seldom present quantified indexes to indicate or forecast the price action of market. In this paper, the stock market is modeled as a dynamic network, in which the vertices refer to listed companies and edges refer to their rank-based correlation based on price series. Characteristics of the network are analyzed and then novel indexes are introduced into market analysis, which are calculated from maximum and fully-connected subnets. The indexes are compared with existing ones and the results confirm that our indexes perform better to indicate the daily trend of market composite index in advance. Via investment simulation, the performance of our indexes is analyzed in detail. The results indicate that the dynamic complex network model could not only serve as a structural description of the financial market, but also work to predict the market and guide investment by indexes.

  11. Stability of spintronic devices based on quantum ring networks

    NASA Astrophysics Data System (ADS)

    Földi, Péter; Kálmán, Orsolya; Peeters, F. M.

    2009-09-01

    Transport properties in mesoscopic networks are investigated, where the strength of the (Rashba-type) spin-orbit coupling is tuned with external gate voltages. We analyze in detail to what extent the ideal behavior and functionality of some promising network-based devices are modified by random (spin-dependent) scattering events and by thermal fluctuations. It is found that although the functionality of these devices is obviously based on the quantum coherence of the transmitted electrons, there is a certain stability: moderate level of errors can be tolerated. For mesoscopic networks made of typical semiconductor materials, we found that when the energy distribution of the input carriers is narrow enough, the devices can operate close to their ideal limits even at relatively high temperature. As an example, we present results for two different networks: one that realizes a Stern-Gerlach device and another that simulates a spin quantum walker. Finally we propose a simple network that can act as a narrow band energy filter even in the presence of random scatterers.

  12. A graph-based system for network-vulnerability analysis

    SciTech Connect

    Swiler, L.P.; Phillips, C.

    1998-06-01

    This paper presents a graph-based approach to network vulnerability analysis. The method is flexible, allowing analysis of attacks from both outside and inside the network. It can analyze risks to a specific network asset, or examine the universe of possible consequences following a successful attack. The graph-based tool can identify the set of attack paths that have a high probability of success (or a low effort cost) for the attacker. The system could be used to test the effectiveness of making configuration changes, implementing an intrusion detection system, etc. The analysis system requires as input a database of common attacks, broken into atomic steps, specific network configuration and topology information, and an attacker profile. The attack information is matched with the network configuration information and an attacker profile to create a superset attack graph. Nodes identify a stage of attack, for example the class of machines the attacker has accessed and the user privilege level he or she has compromised. The arcs in the attack graph represent attacks or stages of attacks. By assigning probabilities of success on the arcs or costs representing level-of-effort for the attacker, various graph algorithms such as shortest-path algorithms can identify the attack paths with the highest probability of success.

  13. Self-healing ATM network based on multilink principles

    NASA Astrophysics Data System (ADS)

    Vanlandegem, Thierry; Vankwikelberge, Patrick; Vanderstreaten, Hans

    1994-01-01

    Self-healing is the ability of a network to reconfigure itself around failures such that calls in progress are not dropped and suffer of no almost no degradation in quality of service. Providing self-healing capabilities in all parts of the future ATM network in a cost effective way is therefore a key challenge. In this paper a new self-healing method based on the multilink concept is presented for dedicated parts of the ATM network, such as, for instance, feeder networks. In the multilink concept that is proposed here, the cells of an ATM connection carried by a multilink are distributed over several physical links. If a physical link supporting the multilink fails, the cells will be distributed among the remaining physical links thus providing self-healing capacity. In this way the quality of service can be maintained at the expense of a higher load on the remaining physical links. The speed of restoration only realize on the detection and signaling of the failure since spare capacity is available on the very multilink. The sharing of spare capacity in addition to the statistical multiplexing gain provides a cost effective self-healing method and leads to a simplified network resource management. The proposed multilink concept is based on extension of the multipath self-routing concept, which is currently applied by Alcatel in its ATM switching fabric.

  14. Neural Network Based Intrusion Detection System for Critical Infrastructures

    SciTech Connect

    Todd Vollmer; Ondrej Linda; Milos Manic

    2009-07-01

    Resiliency and security in control systems such as SCADA and Nuclear plant’s in today’s world of hackers and malware are a relevant concern. Computer systems used within critical infrastructures to control physical functions are not immune to the threat of cyber attacks and may be potentially vulnerable. Tailoring an intrusion detection system to the specifics of critical infrastructures can significantly improve the security of such systems. The IDS-NNM – Intrusion Detection System using Neural Network based Modeling, is presented in this paper. The main contributions of this work are: 1) the use and analyses of real network data (data recorded from an existing critical infrastructure); 2) the development of a specific window based feature extraction technique; 3) the construction of training dataset using randomly generated intrusion vectors; 4) the use of a combination of two neural network learning algorithms – the Error-Back Propagation and Levenberg-Marquardt, for normal behavior modeling. The presented algorithm was evaluated on previously unseen network data. The IDS-NNM algorithm proved to be capable of capturing all intrusion attempts presented in the network communication while not generating any false alerts.

  15. Random Time Identity Based Firewall In Mobile Ad hoc Networks

    NASA Astrophysics Data System (ADS)

    Suman, Patel, R. B.; Singh, Parvinder

    2010-11-01

    A mobile ad hoc network (MANET) is a self-organizing network of mobile routers and associated hosts connected by wireless links. MANETs are highly flexible and adaptable but at the same time are highly prone to security risks due to the open medium, dynamically changing network topology, cooperative algorithms, and lack of centralized control. Firewall is an effective means of protecting a local network from network-based security threats and forms a key component in MANET security architecture. This paper presents a review of firewall implementation techniques in MANETs and their relative merits and demerits. A new approach is proposed to select MANET nodes at random for firewall implementation. This approach randomly select a new node as firewall after fixed time and based on critical value of certain parameters like power backup. This approach effectively balances power and resource utilization of entire MANET because responsibility of implementing firewall is equally shared among all the nodes. At the same time it ensures improved security for MANETs from outside attacks as intruder will not be able to find out the entry point in MANET due to the random selection of nodes for firewall implementation.

  16. Identifying Node Role in Social Network Based on Multiple Indicators

    PubMed Central

    Huang, Shaobin; Lv, Tianyang; Zhang, Xizhe; Yang, Yange; Zheng, Weimin; Wen, Chao

    2014-01-01

    It is a classic topic of social network analysis to evaluate the importance of nodes and identify the node that takes on the role of core or bridge in a network. Because a single indicator is not sufficient to analyze multiple characteristics of a node, it is a natural solution to apply multiple indicators that should be selected carefully. An intuitive idea is to select some indicators with weak correlations to efficiently assess different characteristics of a node. However, this paper shows that it is much better to select the indicators with strong correlations. Because indicator correlation is based on the statistical analysis of a large number of nodes, the particularity of an important node will be outlined if its indicator relationship doesn't comply with the statistical correlation. Therefore, the paper selects the multiple indicators including degree, ego-betweenness centrality and eigenvector centrality to evaluate the importance and the role of a node. The importance of a node is equal to the normalized sum of its three indicators. A candidate for core or bridge is selected from the great degree nodes or the nodes with great ego-betweenness centrality respectively. Then, the role of a candidate is determined according to the difference between its indicators' relationship with the statistical correlation of the overall network. Based on 18 real networks and 3 kinds of model networks, the experimental results show that the proposed methods perform quite well in evaluating the importance of nodes and in identifying the node role. PMID:25089823

  17. Efficient Learning Strategy of Chinese Characters Based on Network Approach

    PubMed Central

    Yan, Xiaoyong; Fan, Ying; Di, Zengru; Havlin, Shlomo; Wu, Jinshan

    2013-01-01

    We develop an efficient learning strategy of Chinese characters based on the network of the hierarchical structural relations between Chinese characters. A more efficient strategy is that of learning the same number of useful Chinese characters in less effort or time. We construct a node-weighted network of Chinese characters, where character usage frequencies are used as node weights. Using this hierarchical node-weighted network, we propose a new learning method, the distributed node weight (DNW) strategy, which is based on a new measure of nodes' importance that considers both the weight of the nodes and its location in the network hierarchical structure. Chinese character learning strategies, particularly their learning order, are analyzed as dynamical processes over the network. We compare the efficiency of three theoretical learning methods and two commonly used methods from mainstream Chinese textbooks, one for Chinese elementary school students and the other for students learning Chinese as a second language. We find that the DNW method significantly outperforms the others, implying that the efficiency of current learning methods of major textbooks can be greatly improved. PMID:23990887

  18. Network based high performance concurrent computing. Progress report, [FY 1991

    SciTech Connect

    Sunderam, V.S.

    1991-12-31

    The overall objectives of this project are to investigate research issues pertaining to programming tools and efficiency issues in network based concurrent computing systems. The basis for these efforts is the PVM project that evolved during my visits to Oak Ridge Laboratories under the DOE Faculty Research Participation program; I continue to collaborate with researchers at Oak Ridge on some portions of the project.

  19. Neural network-based retrieval from software reuse repositories

    NASA Technical Reports Server (NTRS)

    Eichmann, David A.; Srinivas, Kankanahalli

    1992-01-01

    A significant hurdle confronts the software reuser attempting to select candidate components from a software repository - discriminating between those components without resorting to inspection of the implementation(s). We outline an approach to this problem based upon neural networks which avoids requiring the repository administrators to define a conceptual closeness graph for the classification vocabulary.

  20. Combine harvester monitor system based on wireless sensor network

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A measurement method based on Wireless Sensor Network (WSN) was developed to monitor the working condition of combine harvester for remote application. Three JN5139 modules were chosen for sensor data acquisition and another two as a router and a coordinator, which could create a tree topology netwo...

  1. Neural Network Based System for Equipment Startup Surveillance

    Energy Science and Technology Software Center (ESTSC)

    1996-12-18

    NEBSESS is a system for equipment surveillance and fault detection which relies on a neural-network based means for diagnosing disturbances during startup and for automatically actuating the Sequential Probability Ratio Test (SPRT) as a signal validation means during steady-state operation.

  2. Impact of Information based Classification on Network Epidemics.

    PubMed

    Mishra, Bimal Kumar; Haldar, Kaushik; Sinha, Durgesh Nandini

    2016-01-01

    Formulating mathematical models for accurate approximation of malicious propagation in a network is a difficult process because of our inherent lack of understanding of several underlying physical processes that intrinsically characterize the broader picture. The aim of this paper is to understand the impact of available information in the control of malicious network epidemics. A 1-n-n-1 type differential epidemic model is proposed, where the differentiality allows a symptom based classification. This is the first such attempt to add such a classification into the existing epidemic framework. The model is incorporated into a five class system called the DifEpGoss architecture. Analysis reveals an epidemic threshold, based on which the long-term behavior of the system is analyzed. In this work three real network datasets with 22002, 22469 and 22607 undirected edges respectively, are used. The datasets show that classification based prevention given in the model can have a good role in containing network epidemics. Further simulation based experiments are used with a three category classification of attack and defense strengths, which allows us to consider 27 different possibilities. These experiments further corroborate the utility of the proposed model. The paper concludes with several interesting results. PMID:27329348

  3. Impact of Information based Classification on Network Epidemics

    PubMed Central

    Mishra, Bimal Kumar; Haldar, Kaushik; Sinha, Durgesh Nandini

    2016-01-01

    Formulating mathematical models for accurate approximation of malicious propagation in a network is a difficult process because of our inherent lack of understanding of several underlying physical processes that intrinsically characterize the broader picture. The aim of this paper is to understand the impact of available information in the control of malicious network epidemics. A 1-n-n-1 type differential epidemic model is proposed, where the differentiality allows a symptom based classification. This is the first such attempt to add such a classification into the existing epidemic framework. The model is incorporated into a five class system called the DifEpGoss architecture. Analysis reveals an epidemic threshold, based on which the long-term behavior of the system is analyzed. In this work three real network datasets with 22002, 22469 and 22607 undirected edges respectively, are used. The datasets show that classification based prevention given in the model can have a good role in containing network epidemics. Further simulation based experiments are used with a three category classification of attack and defense strengths, which allows us to consider 27 different possibilities. These experiments further corroborate the utility of the proposed model. The paper concludes with several interesting results. PMID:27329348

  4. Impact of Information based Classification on Network Epidemics

    NASA Astrophysics Data System (ADS)

    Mishra, Bimal Kumar; Haldar, Kaushik; Sinha, Durgesh Nandini

    2016-06-01

    Formulating mathematical models for accurate approximation of malicious propagation in a network is a difficult process because of our inherent lack of understanding of several underlying physical processes that intrinsically characterize the broader picture. The aim of this paper is to understand the impact of available information in the control of malicious network epidemics. A 1-n-n-1 type differential epidemic model is proposed, where the differentiality allows a symptom based classification. This is the first such attempt to add such a classification into the existing epidemic framework. The model is incorporated into a five class system called the DifEpGoss architecture. Analysis reveals an epidemic threshold, based on which the long-term behavior of the system is analyzed. In this work three real network datasets with 22002, 22469 and 22607 undirected edges respectively, are used. The datasets show that classification based prevention given in the model can have a good role in containing network epidemics. Further simulation based experiments are used with a three category classification of attack and defense strengths, which allows us to consider 27 different possibilities. These experiments further corroborate the utility of the proposed model. The paper concludes with several interesting results.

  5. Design Considerations in Developing a Web-Based Mentor Network.

    ERIC Educational Resources Information Center

    Sumner, Todd

    This paper describes a Web-based mentor network designed to pair students in rural independent schools with undergraduates at selected liberal arts colleges. It is one of nine central program elements that constitute the Proteus(TM) system, a multimedia technologies architecture that supports distributed collaborations and work undertaken in the…

  6. SpecialNet. A National Computer-Based Communications Network.

    ERIC Educational Resources Information Center

    Morin, Alfred J.

    1986-01-01

    "SpecialNet," a computer-based communications network for educators at all administrative levels, has been established and is managed by National Systems Management, Inc. Users can send and receive electronic mail, share information on electronic bulletin boards, participate in electronic conferences, and send reports and other documents to each…

  7. Social Networks-Based Adaptive Pairing Strategy for Cooperative Learning

    ERIC Educational Resources Information Center

    Chuang, Po-Jen; Chiang, Ming-Chao; Yang, Chu-Sing; Tsai, Chun-Wei

    2012-01-01

    In this paper, we propose a grouping strategy to enhance the learning and testing results of students, called Pairing Strategy (PS). The proposed method stems from the need of interactivity and the desire of cooperation in cooperative learning. Based on the social networks of students, PS provides members of the groups to learn from or mimic…

  8. Neural network-based finite horizon stochastic optimal control design for nonlinear networked control systems.

    PubMed

    Xu, Hao; Jagannathan, Sarangapani

    2015-03-01

    The stochastic optimal control of nonlinear networked control systems (NNCSs) using neuro-dynamic programming (NDP) over a finite time horizon is a challenging problem due to terminal constraints, system uncertainties, and unknown network imperfections, such as network-induced delays and packet losses. Since the traditional iteration or time-based infinite horizon NDP schemes are unsuitable for NNCS with terminal constraints, a novel time-based NDP scheme is developed to solve finite horizon optimal control of NNCS by mitigating the above-mentioned challenges. First, an online neural network (NN) identifier is introduced to approximate the control coefficient matrix that is subsequently utilized in conjunction with the critic and actor NNs to determine a time-based stochastic optimal control input over finite horizon in a forward-in-time and online manner. Eventually, Lyapunov theory is used to show that all closed-loop signals and NN weights are uniformly ultimately bounded with ultimate bounds being a function of initial conditions and final time. Moreover, the approximated control input converges close to optimal value within finite time. The simulation results are included to show the effectiveness of the proposed scheme. PMID:25720004

  9. Integrated Genomic and Network-Based Analyses of Complex Diseases and Human Disease Network.

    PubMed

    Al-Harazi, Olfat; Al Insaif, Sadiq; Al-Ajlan, Monirah A; Kaya, Namik; Dzimiri, Nduna; Colak, Dilek

    2016-06-20

    A disease phenotype generally reflects various pathobiological processes that interact in a complex network. The highly interconnected nature of the human protein interaction network (interactome) indicates that, at the molecular level, it is difficult to consider diseases as being independent of one another. Recently, genome-wide molecular measurements, data mining and bioinformatics approaches have provided the means to explore human diseases from a molecular basis. The exploration of diseases and a system of disease relationships based on the integration of genome-wide molecular data with the human interactome could offer a powerful perspective for understanding the molecular architecture of diseases. Recently, subnetwork markers have proven to be more robust and reliable than individual biomarker genes selected based on gene expression profiles alone, and achieve higher accuracy in disease classification. We have applied one of these methodologies to idiopathic dilated cardiomyopathy (IDCM) data that we have generated using a microarray and identified significant subnetworks associated with the disease. In this paper, we review the recent endeavours in this direction, and summarize the existing methodologies and computational tools for network-based analysis of complex diseases and molecular relationships among apparently different disorders and human disease network. We also discuss the future research trends and topics of this promising field. PMID:27318646

  10. Content-based network model with duplication and divergence

    NASA Astrophysics Data System (ADS)

    Şengün, Yasemin; Erzan, Ayşe

    2006-06-01

    We construct a minimal content-based realization of the duplication and divergence model of genomic networks introduced by Wagner [Proc. Natl. Acad. Sci. 91 (1994) 4387] and investigate the scaling properties of the directed degree distribution and clustering coefficient. We find that the content-based network exhibits crossover between two scaling regimes, with log-periodic oscillations for large degrees. These features are not present in the original gene duplication model, but inherent in the content-based model of Balcan and Erzan. The scaling form of the degree distribution of the content-based model turns out to be robust under duplication and divergence, with some re-adjustment of the scaling exponents, while the out-clustering coefficient goes over from a weak power-law dependence on the degree, to an exponential decay under mutations which include splitting and merging of strings.

  11. Predicting healthy older adult's brain age based on structural connectivity networks using artificial neural networks.

    PubMed

    Lin, Lan; Jin, Cong; Fu, Zhenrong; Zhang, Baiwen; Bin, Guangyu; Wu, Shuicai

    2016-03-01

    Brain ageing is followed by changes of the connectivity of white matter (WM) and changes of the grey matter (GM) concentration. Neurodegenerative disease is more vulnerable to an accelerated brain ageing, which is associated with prospective cognitive decline and disease severity. Accurate detection of accelerated ageing based on brain network analysis has a great potential for early interventions designed to hinder atypical brain changes. To capture the brain ageing, we proposed a novel computational approach for modeling the 112 normal older subjects (aged 50-79 years) brain age by connectivity analyses of networks of the brain. Our proposed method applied principal component analysis (PCA) to reduce the redundancy in network topological parameters. Back propagation artificial neural network (BPANN) improved by hybrid genetic algorithm (GA) and Levenberg-Marquardt (LM) algorithm is established to model the relation among principal components (PCs) and brain age. The predicted brain age is strongly correlated with chronological age (r=0.8). The model has mean absolute error (MAE) of 4.29 years. Therefore, we believe the method can provide a possible way to quantitatively describe the typical and atypical network organization of human brain and serve as a biomarker for presymptomatic detection of neurodegenerative diseases in the future. PMID:26718834

  12. Electronic implementation of associative memory based on neural network models

    NASA Technical Reports Server (NTRS)

    Moopenn, A.; Lambe, John; Thakoor, A. P.

    1987-01-01

    An electronic embodiment of a neural network based associative memory in the form of a binary connection matrix is described. The nature of false memory errors, their effect on the information storage capacity of binary connection matrix memories, and a novel technique to eliminate such errors with the help of asymmetrical extra connections are discussed. The stability of the matrix memory system incorporating a unique local inhibition scheme is analyzed in terms of local minimization of an energy function. The memory's stability, dynamic behavior, and recall capability are investigated using a 32-'neuron' electronic neural network memory with a 1024-programmable binary connection matrix.

  13. Neural network based diagonal decoupling control of powered wheelchair systems.

    PubMed

    Nguyen, Tuan Nghia; Su, Steven; Nguyen, Hung T

    2014-03-01

    This paper proposes an advanced diagonal decoupling control method for powered wheelchair systems. This control method is based on a combination of the systematic diagonalization technique and the neural network control design. As such, this control method reduces coupling effects on a multivariable system, leading to independent control design procedures. Using an obtained dynamic model, the problem of the plant's Jacobian calculation is eliminated in a neural network control design. The effectiveness of the proposed control method is verified in a real-time implementation on a powered wheelchair system. The obtained results confirm that robustness and desired performance of the overall system are guaranteed, even under parameter uncertainty effects. PMID:23981543

  14. Evaluation of social network user sentiments based on fuzzy sets

    NASA Astrophysics Data System (ADS)

    Luneva, E. E.; Banokin, P. I.; Yefremov, A. A.

    2015-10-01

    The article introduces social network user sentiment evaluation with proposed technique based on fuzzy sets. The advantage of proposed technique consists in ability to take into account user's influence as well as the fact that a user could be an author of several messages. Results presented in this paper can be used in mechanical engineering to analyze reviews on products as well as in robotics for developing user communication interface. The paper contains experimental data and shows the steps of sentiment value calculation of resulting messages on a certain topic. Application of proposed technique is demonstrated on experimental data from Twitter social network.

  15. Identifying influential nodes in weighted networks based on evidence theory

    NASA Astrophysics Data System (ADS)

    Wei, Daijun; Deng, Xinyang; Zhang, Xiaoge; Deng, Yong; Mahadevan, Sankaran

    2013-05-01

    The design of an effective ranking method to identify influential nodes is an important problem in the study of complex networks. In this paper, a new centrality measure is proposed based on the Dempster-Shafer evidence theory. The proposed measure trades off between the degree and strength of every node in a weighted network. The influences of both the degree and the strength of each node are represented by basic probability assignment (BPA). The proposed centrality measure is determined by the combination of these BPAs. Numerical examples are used to illustrate the effectiveness of the proposed method.

  16. Ion beam analysis based on cellular nonlinear networks

    NASA Astrophysics Data System (ADS)

    Senger, V.; Tetzlaff, R.; Reichau, H.; Ratzinger, U.

    2011-07-01

    The development of a non- destructive measurement method for ion beam parameters has been treated in various projects. Although results are promising, the high complexity of beam dynamics has made it impossible to implement a real time process control up to now. In this paper we will propose analysing methods based on the dynamics of Cellular Nonlinear Networks (CNN) that can be implemented on pixel parallel CNN based architectures and yield satisfying results even at low resolutions.

  17. Bivalent vaccine platform based on Japanese encephalitis virus (JEV) elicits neutralizing antibodies against JEV and hepatitis C virus.

    PubMed

    Saga, Ryohei; Fujimoto, Akira; Watanabe, Noriyuki; Matsuda, Mami; Hasegawa, Makoto; Watashi, Koichi; Aizaki, Hideki; Nakamura, Noriko; Tajima, Shigeru; Takasaki, Tomohiko; Konishi, Eiji; Kato, Takanobu; Kohara, Michinori; Takeyama, Haruko; Wakita, Takaji; Suzuki, Ryosuke

    2016-01-01

    Directly acting antivirals recently have become available for the treatment of hepatitis C virus (HCV) infection, but there is no prophylactic vaccine for HCV. In the present study, we took advantage of the properties of Japanese encephalitis virus (JEV) to develop antigens for use in a HCV vaccine. Notably, the surface-exposed JEV envelope protein is tolerant of inserted foreign epitopes, permitting display of novel antigens. We identified 3 positions that permitted insertion of the HCV E2 neutralization epitope recognized by HCV1 antibody. JEV subviral particles (SVP) containing HCV-neutralization epitope (SVP-E2) were purified from culture supernatant by gel chromatography. Sera from mice immunized with SVP-E2 inhibited infection by JEV and by trans-complemented HCV particles (HCVtcp) derived from multi-genotypic viruses, whereas sera from mice immunized with synthetic E2 peptides did not show any neutralizing activity. Furthermore, sera from mice immunized with SVP-E2 neutralized HCVtcp with N415K escape mutation in E2. As with the SVP-E2 epitope-displaying particles, JEV SVPs with HCV E1 epitope also elicited neutralizing antibodies against HCV. Thus, this novel platform harboring foreign epitopes on the surface of the particle may facilitate the development of a bivalent vaccine against JEV and other pathogens. PMID:27345289

  18. Bivalent vaccine platform based on Japanese encephalitis virus (JEV) elicits neutralizing antibodies against JEV and hepatitis C virus

    PubMed Central

    Saga, Ryohei; Fujimoto, Akira; Watanabe, Noriyuki; Matsuda, Mami; Hasegawa, Makoto; Watashi, Koichi; Aizaki, Hideki; Nakamura, Noriko; Tajima, Shigeru; Takasaki, Tomohiko; Konishi, Eiji; Kato, Takanobu; Kohara, Michinori; Takeyama, Haruko; Wakita, Takaji; Suzuki, Ryosuke

    2016-01-01

    Directly acting antivirals recently have become available for the treatment of hepatitis C virus (HCV) infection, but there is no prophylactic vaccine for HCV. In the present study, we took advantage of the properties of Japanese encephalitis virus (JEV) to develop antigens for use in a HCV vaccine. Notably, the surface-exposed JEV envelope protein is tolerant of inserted foreign epitopes, permitting display of novel antigens. We identified 3 positions that permitted insertion of the HCV E2 neutralization epitope recognized by HCV1 antibody. JEV subviral particles (SVP) containing HCV-neutralization epitope (SVP-E2) were purified from culture supernatant by gel chromatography. Sera from mice immunized with SVP-E2 inhibited infection by JEV and by trans-complemented HCV particles (HCVtcp) derived from multi-genotypic viruses, whereas sera from mice immunized with synthetic E2 peptides did not show any neutralizing activity. Furthermore, sera from mice immunized with SVP-E2 neutralized HCVtcp with N415K escape mutation in E2. As with the SVP-E2 epitope-displaying particles, JEV SVPs with HCV E1 epitope also elicited neutralizing antibodies against HCV. Thus, this novel platform harboring foreign epitopes on the surface of the particle may facilitate the development of a bivalent vaccine against JEV and other pathogens. PMID:27345289

  19. Social Networks and Community-Based Natural Resource Management

    NASA Astrophysics Data System (ADS)

    Lauber, T. Bruce; Decker, Daniel J.; Knuth, Barbara A.

    2008-10-01

    We conducted case studies of three successful examples of collaborative, community-based natural resource conservation and development. Our purpose was to: (1) identify the functions served by interactions within the social networks of involved stakeholders; (2) describe key structural properties of these social networks; and (3) determine how these structural properties varied when the networks were serving different functions. The case studies relied on semi-structured, in-depth interviews of 8 to 11 key stakeholders at each site who had played a significant role in the collaborative projects. Interview questions focused on the roles played by key stakeholders and the functions of interactions between them. Interactions allowed the exchange of ideas, provided access to funding, and enabled some stakeholders to influence others. The exchange of ideas involved the largest number of stakeholders, the highest percentage of local stakeholders, and the highest density of interactions. Our findings demonstrated the value of tailoring strategies for involving stakeholders to meet different needs during a collaborative, community-based natural resource management project. Widespread involvement of local stakeholders may be most appropriate when ideas for a project are being developed. During efforts to exert influence to secure project approvals or funding, however, involving specific individuals with political connections or influence on possible sources of funds may be critical. Our findings are consistent with past work that has postulated that social networks may require specific characteristics to meet different needs in community-based environmental management.

  20. Network-based Prediction of Cancer under Genetic Storm

    PubMed Central

    Ay, Ahmet; Gong, Dihong; Kahveci, Tamer

    2014-01-01

    Classification of cancer patients using traditional methods is a challenging task in the medical practice. Owing to rapid advances in microarray technologies, currently expression levels of thousands of genes from individual cancer patients can be measured. The classification of cancer patients by supervised statistical learning algorithms using the gene expression datasets provides an alternative to the traditional methods. Here we present a new network-based supervised classification technique, namely the NBC method. We compare NBC to five traditional classification techniques (support vector machines (SVM), k-nearest neighbor (kNN), naïve Bayes (NB), C4.5, and random forest (RF)) using 50–300 genes selected by five feature selection methods. Our results on five large cancer datasets demonstrate that NBC method outperforms traditional classification techniques. Our analysis suggests that using symmetrical uncertainty (SU) feature selection method with NBC method provides the most accurate classification strategy. Finally, in-depth analysis of the correlation-based co-expression networks chosen by our network-based classifier in different cancer classes shows that there are drastic changes in the network models of different cancer types. PMID:25368507

  1. Home medical monitoring network based on embedded technology

    NASA Astrophysics Data System (ADS)

    Liu, Guozhong; Deng, Wenyi; Yan, Bixi; Lv, Naiguang

    2006-11-01

    Remote medical monitoring network for long-term monitoring of physiological variables would be helpful for recovery of patients as people are monitored at more comfortable conditions. Furthermore, long-term monitoring would be beneficial to investigate slowly developing deterioration in wellness status of a subject and provide medical treatment as soon as possible. The home monitor runs on an embedded microcomputer Rabbit3000 and interfaces with different medical monitoring module through serial ports. The network based on asymmetric digital subscriber line (ADSL) or local area network (LAN) is established and a client - server model, each embedded home medical monitor is client and the monitoring center is the server, is applied to the system design. The client is able to provide its information to the server when client's request of connection to the server is permitted. The monitoring center focuses on the management of the communications, the acquisition of medical data, and the visualization and analysis of the data, etc. Diagnosing model of sleep apnea syndrome is built basing on ECG, heart rate, respiration wave, blood pressure, oxygen saturation, air temperature of mouth cavity or nasal cavity, so sleep status can be analyzed by physiological data acquired as people in sleep. Remote medical monitoring network based on embedded micro Internetworking technology have advantages of lower price, convenience and feasibility, which have been tested by the prototype.

  2. Fitness consequences of centrality in mutualistic individual-based networks

    PubMed Central

    Gómez, José M.; Perfectti, Francisco

    2012-01-01

    The relationships among the members of a population can be visualized using individual networks, where each individual is a node connected to each other by means of links describing the interactions. The centrality of a given node captures its importance within the network. We hypothesize that in mutualistic networks, the centrality of a node should benefit its fitness. We test this idea studying eight individual-based networks originated from the interaction between Erysimum mediohispanicum and its flower visitors. In these networks, each plant was considered a node and was connected to conspecifics sharing flower visitors. Centrality indicates how well connected is a given E. mediohispanicum individual with the rest of the co-occurring conspecifics because of sharing flower visitors. The centrality was estimated by three network metrics: betweenness, closeness and degree. The complex relationship between centrality, phenotype and fitness was explored by structural equation modelling. We found that the centrality of a plant was related to its fitness, with plants occupying central positions having higher fitness than those occupying peripheral positions. The structural equation models (SEMs) indicated that the centrality effect on fitness was not merely an effect of the abundance of visits and the species richness of visitors. Centrality has an effect even when simultaneously accounting for these predictors. The SEMs also indicated that the centrality effect on fitness was because of the specific phenotype of each plant, with attractive plants occupying central positions in networks, in relation to the distribution of conspecific phenotypes. This finding suggests that centrality, owing to its dependence on social interactions, may be an appropriate surrogate for the interacting phenotype of individuals. PMID:22158957

  3. Broadband packet switches based on dilated interconnection networks

    NASA Astrophysics Data System (ADS)

    Lee, Tony T.; Liew, Soung C.

    1994-02-01

    A theoretical foundation for evaluation and comparison of a very broad spectrum of fast packet-switching techniques is developed in this paper. Based on this framework, we investigate the complexity of various packet switch designs, and demonstrate the advantage of dilation as a switch-design technique. Packet switches are classified either as loss systems or waiting systems, according to whether packets losing contention are dropped or queued. In a loss system, the packet loss probability can be made arbitrary small by providing enough paths between inputs and outputs. We focus on the question: How does the switch complexity grow as a function of switch size for a given loss probability requirement? A uniform approach to this problem is developed here. We show that for an N x N switch, the required number of switch elements for both the parallel-banyan network and the tandem-banyan network is of order N(log N)(sup 2), whereas the complexity of a dilated-banyan network is of order N log N(log log N). Within the class of waiting systems, we show that the parallel banyan networks in a Batcher-parallel-banyan network can be replaced by a dilated-banyan network without sacrificing the nonblocking property. Thus, as with parallelization, dilation can also be used to increase the throughput of a waiting system. In addition, we also explore the application of dilation in a large modular switch design which is realized by an interconnection structure consisting of Batcher-dilated-banyan networks and statistical multiplexers.

  4. Spectrum-Based and Collaborative Network Topology Analysis and Visualization

    ERIC Educational Resources Information Center

    Hu, Xianlin

    2013-01-01

    Networks are of significant importance in many application domains, such as World Wide Web and social networks, which often embed rich topological information. Since network topology captures the organization of network nodes and links, studying network topology is very important to network analysis. In this dissertation, we study networks by…

  5. Models of social networks based on social distance attachment

    NASA Astrophysics Data System (ADS)

    Boguñá, Marián; Pastor-Satorras, Romualdo; Díaz-Guilera, Albert; Arenas, Alex

    2004-11-01

    We propose a class of models of social network formation based on a mathematical abstraction of the concept of social distance. Social distance attachment is represented by the tendency of peers to establish acquaintances via a decreasing function of the relative distance in a representative social space. We derive analytical results (corroborated by extensive numerical simulations), showing that the model reproduces the main statistical characteristics of real social networks: large clustering coefficient, positive degree correlations, and the emergence of a hierarchy of communities. The model is confronted with the social network formed by people that shares confidential information using the Pretty Good Privacy (PGP) encryption algorithm, the so-called web of trust of PGP.

  6. Models of social networks based on social distance attachment.

    PubMed

    Boguñá, Marián; Pastor-Satorras, Romualdo; Díaz-Guilera, Albert; Arenas, Alex

    2004-11-01

    We propose a class of models of social network formation based on a mathematical abstraction of the concept of social distance. Social distance attachment is represented by the tendency of peers to establish acquaintances via a decreasing function of the relative distance in a representative social space. We derive analytical results (corroborated by extensive numerical simulations), showing that the model reproduces the main statistical characteristics of real social networks: large clustering coefficient, positive degree correlations, and the emergence of a hierarchy of communities. The model is confronted with the social network formed by people that shares confidential information using the Pretty Good Privacy (PGP) encryption algorithm, the so-called web of trust of PGP. PMID:15600707

  7. Numerical analysis of modeling based on improved Elman neural network.

    PubMed

    Jie, Shao; Li, Wang; WeiSong, Zhao; YaQin, Zhong; Malekian, Reza

    2014-01-01

    A modeling based on the improved Elman neural network (IENN) is proposed to analyze the nonlinear circuits with the memory effect. The hidden layer neurons are activated by a group of Chebyshev orthogonal basis functions instead of sigmoid functions in this model. The error curves of the sum of squared error (SSE) varying with the number of hidden neurons and the iteration step are studied to determine the number of the hidden layer neurons. Simulation results of the half-bridge class-D power amplifier (CDPA) with two-tone signal and broadband signals as input have shown that the proposed behavioral modeling can reconstruct the system of CDPAs accurately and depict the memory effect of CDPAs well. Compared with Volterra-Laguerre (VL) model, Chebyshev neural network (CNN) model, and basic Elman neural network (BENN) model, the proposed model has better performance. PMID:25054172

  8. Evaluation of vehicle ride comfort based on neural network

    NASA Astrophysics Data System (ADS)

    Gao, Yinhan; Tang, Rongjiang; Liang, Jie; Shen, Shen; Liang, Jie; Sun, Huihui

    2010-08-01

    The relationship between subjective ride comfort in a vehicle seat and human whole-body vibration can be modeled using frequency weightings and rms(root mean square) averaging as specified in ISO2631. However, recent studies indicate that, there are some flaws in the relationship between subjective response and objective vibration given by the ISO2631.This paper presents an alternative approach based on neural network model. Time-domain vibration acceleration signals are processed as neural network inputs, subjective evaluation results are quantified as outputs, and the weights of neural networks are used as frequency weighting coefficients to evaluate the vehicle ride comfort. The method has been used to evaluate the ride comfort on a number of conditions with good results achieved.

  9. Query-Based Outlier Detection in Heterogeneous Information Networks

    PubMed Central

    Kuck, Jonathan; Zhuang, Honglei; Yan, Xifeng; Cam, Hasan; Han, Jiawei

    2015-01-01

    Outlier or anomaly detection in large data sets is a fundamental task in data science, with broad applications. However, in real data sets with high-dimensional space, most outliers are hidden in certain dimensional combinations and are relative to a user’s search space and interest. It is often more effective to give power to users and allow them to specify outlier queries flexibly, and the system will then process such mining queries efficiently. In this study, we introduce the concept of query-based outlier in heterogeneous information networks, design a query language to facilitate users to specify such queries flexibly, define a good outlier measure in heterogeneous networks, and study how to process outlier queries efficiently in large data sets. Our experiments on real data sets show that following such a methodology, interesting outliers can be defined and uncovered flexibly and effectively in large heterogeneous networks. PMID:27064397

  10. Developing Visualization Techniques for Semantics-based Information Networks

    NASA Technical Reports Server (NTRS)

    Keller, Richard M.; Hall, David R.

    2003-01-01

    Information systems incorporating complex network structured information spaces with a semantic underpinning - such as hypermedia networks, semantic networks, topic maps, and concept maps - are being deployed to solve some of NASA s critical information management problems. This paper describes some of the human interaction and navigation problems associated with complex semantic information spaces and describes a set of new visual interface approaches to address these problems. A key strategy is to leverage semantic knowledge represented within these information spaces to construct abstractions and views that will be meaningful to the human user. Human-computer interaction methodologies will guide the development and evaluation of these approaches, which will benefit deployed NASA systems and also apply to information systems based on the emerging Semantic Web.

  11. Toward next-generation optical networks: a network operator perspective based on experimental tests and economic analysis

    NASA Astrophysics Data System (ADS)

    Xiao, Xiaojun; Du, Chunsheng; Zhou, Rongsheng

    2004-04-01

    As a result of data traffic"s exponential growth, network is currently evolving from fixed circuit switched services to dynamic packet switched services, which has brought unprecedented changes to the existing transport infrastructure. It is generally agreed that automatic switched optical network (ASON) is one of the promising solutions for the next generation optical networks. In this paper, we present the results of our experimental tests and economic analysis on ASON. The intention of this paper is to present our perspective, in terms of evolution strategy toward ASON, on next generation optical networks. It is shown through experimental tests that the performance of current Pre-standard ASON enabled equipments satisfies the basic requirements of network operators and is ready for initial deployment. The results of the economic analysis show that network operators can be benefit from the deployment of ASON from three sides. Firstly, ASON can reduce the CAPEX for network expanding by integrating multiple ADM & DCS into one box. Secondly, ASON can reduce the OPEX for network operation by introducing automatic resource control scheme. Finally, ASON can increase margin revenue by providing new optical network services such as Bandwidth on Demand, optical VPN etc. Finally, the evolution strategy is proposed as our perspective toward next generation optical networks. We hope the evolution strategy introduced may be helpful for the network operators to gracefully migrate their fixed ring based legacy networks to next generation dynamic mesh based network.

  12. Timescale analysis of rule-based biochemical reaction networks

    PubMed Central

    Klinke, David J.; Finley, Stacey D.

    2012-01-01

    The flow of information within a cell is governed by a series of protein-protein interactions that can be described as a reaction network. Mathematical models of biochemical reaction networks can be constructed by repetitively applying specific rules that define how reactants interact and what new species are formed upon reaction. To aid in understanding the underlying biochemistry, timescale analysis is one method developed to prune the size of the reaction network. In this work, we extend the methods associated with timescale analysis to reaction rules instead of the species contained within the network. To illustrate this approach, we applied timescale analysis to a simple receptor-ligand binding model and a rule-based model of Interleukin-12 (IL-12) signaling in näive CD4+ T cells. The IL-12 signaling pathway includes multiple protein-protein interactions that collectively transmit information; however, the level of mechanistic detail sufficient to capture the observed dynamics has not been justified based upon the available data. The analysis correctly predicted that reactions associated with JAK2 and TYK2 binding to their corresponding receptor exist at a pseudo-equilibrium. In contrast, reactions associated with ligand binding and receptor turnover regulate cellular response to IL-12. An empirical Bayesian approach was used to estimate the uncertainty in the timescales. This approach complements existing rank- and flux-based methods that can be used to interrogate complex reaction networks. Ultimately, timescale analysis of rule-based models is a computational tool that can be used to reveal the biochemical steps that regulate signaling dynamics. PMID:21954150

  13. Ferrocene-based compartmental ligand for the assembly of neutral Zn(II)/Ln(III) heterometallic complexes.

    PubMed

    Chandrasekhar, Vadapalli; Chakraborty, Amit; Sañudo, E Carolina

    2013-10-01

    A ferrocene-based compartmental ligand, H2L, was synthesized by the reaction of diacetyl ferrocene with hydrazine hydrate followed by a condensation reaction with o-vanillin. [L](2-) possesses a dual coordination pocket, an inner pocket of 2 imino nitrogens and two phenolate oxygens and an outer pocket of two phenolate and two methoxy oxygen atoms. Utilizing this ligand, several Zn(II)/Ln(III) heterobimetallic complexes were assembled: [LZn(μ-OAc)Dy(NO3)2] (2), [LZn(μ-OAc)Tb(NO3)2] (3), [LZn(μ-OAc)Gd(NO3)2·2CHCl3] (4), [LZn(μ-OAc)Er(NO3)2] (5), [LZn(μ-OAc)Ho(NO3)2] (6), [LZn(μ-OAc)Eu(NO3)2] (7). All of these metal complexes are neutral and isostructural: the Zn(II) ion occupies the inner coordination pocket while the Ln(III) ion occupies the outer coordination pocket of the doubly deprotonated ligand [L](2-). Zn(II) has a coordination number of 5 (2N, 3O) in a square pyramidal coordination geometry while Ln(III) has a coordination number of 9 (9O) in a distorted tricapped trigonal prismatic geometry. Zn(II) and the 4f metal ion are bridged to each other by two phenolate oxygen atoms and an acetate ligand. ESI-MS reveals that 2-7 retain their structural integrity in solution. Cyclic voltammetry of 1-7 revealed a quasi-reversible oxidation (involving the ferrocene motif) and an irreversible reduction of the hydrazone unit. Magnetic studies of 2, 3 and 6 were carried out. Ac susceptibility studies did not reveal slow relaxation of magnetization. PMID:23893198

  14. Structural controllability of complex networks based on preferential matching.

    PubMed

    Zhang, Xizhe; Lv, Tianyang; Yang, XueYing; Zhang, Bin

    2014-01-01

    Minimum driver node sets (MDSs) play an important role in studying the structural controllability of complex networks. Recent research has shown that MDSs tend to avoid high-degree nodes. However, this observation is based on the analysis of a small number of MDSs, because enumerating all of the MDSs of a network is a #P problem. Therefore, past research has not been sufficient to arrive at a convincing conclusion. In this paper, first, we propose a preferential matching algorithm to find MDSs that have a specific degree property. Then, we show that the MDSs obtained by preferential matching can be composed of high- and medium-degree nodes. Moreover, the experimental results also show that the average degree of the MDSs of some networks tends to be greater than that of the overall network, even when the MDSs are obtained using previous research method. Further analysis shows that whether the driver nodes tend to be high-degree nodes or not is closely related to the edge direction of the network. PMID:25375628

  15. Structural Controllability of Complex Networks Based on Preferential Matching

    PubMed Central

    Zhang, Xizhe; Lv, Tianyang; Yang, XueYing; Zhang, Bin

    2014-01-01

    Minimum driver node sets (MDSs) play an important role in studying the structural controllability of complex networks. Recent research has shown that MDSs tend to avoid high-degree nodes. However, this observation is based on the analysis of a small number of MDSs, because enumerating all of the MDSs of a network is a #P problem. Therefore, past research has not been sufficient to arrive at a convincing conclusion. In this paper, first, we propose a preferential matching algorithm to find MDSs that have a specific degree property. Then, we show that the MDSs obtained by preferential matching can be composed of high- and medium-degree nodes. Moreover, the experimental results also show that the average degree of the MDSs of some networks tends to be greater than that of the overall network, even when the MDSs are obtained using previous research method. Further analysis shows that whether the driver nodes tend to be high-degree nodes or not is closely related to the edge direction of the network. PMID:25375628

  16. A graph-based network-vulnerability analysis system

    SciTech Connect

    Swiler, L.P.; Phillips, C.; Gaylor, T.

    1998-01-01

    This report presents a graph-based approach to network vulnerability analysis. The method is flexible, allowing analysis of attacks from both outside and inside the network. It can analyze risks to a specific network asset, or examine the universe of possible consequences following a successful attack. The analysis system requires as input a database of common attacks, broken into atomic steps, specific network configuration and topology information, and an attacker profile. The attack information is matched with the network configuration information and an attacker profile to create a superset attack graph. Nodes identify a stage of attack, for example the class of machines the attacker has accessed and the user privilege level he or she has compromised. The arcs in the attack graph represent attacks or stages of attacks. By assigning probabilities of success on the arcs or costs representing level-of-effort for the attacker, various graph algorithms such as shortest-path algorithms can identify the attack paths with the highest probability of success.

  17. A graph-based network-vulnerability analysis system

    SciTech Connect

    Swiler, L.P.; Phillips, C.; Gaylor, T.

    1998-05-03

    This paper presents a graph based approach to network vulnerability analysis. The method is flexible, allowing analysis of attacks from both outside and inside the network. It can analyze risks to a specific network asset, or examine the universe of possible consequences following a successful attack. The analysis system requires as input a database of common attacks, broken into atomic steps, specific network configuration and topology information, and an attacker profile. The attack information is matched with the network configuration information and an attacker profile to create a superset attack graph. Nodes identify a stage of attack, for example the class of machines the attacker has accessed and the user privilege level he or she has compromised. The arcs in the attack graph represent attacks or stages of attacks. By assigning probabilities of success on the arcs or costs representing level of effort for the attacker, various graph algorithms such as shortest path algorithms can identify the attack paths with the highest probability of success.

  18. An efficient query mechanism base on P2P networks

    NASA Astrophysics Data System (ADS)

    Wang, Xiaohua; Mu, Aiqin; Zhao, Defang

    2013-07-01

    How to implement the efficient query is the key problem deployed on P2P networks. This paper analyses the shortage of several query algorithm, and presents a new algorithm DDI, which means distributed searching with double indices. It discusses the popularity of documents and the linking status of the networks, and calculates the availability of the nodes in whole network, determines the route of the query process. It compares the items of time using, the quantity of requests and update information by the emulate experiments. Along with the rapid development of computer network technology, peer-to-peer (referred to as P2P) network research has gradually become mature, and it is widely used in different fields, some large P2P computing project has entered the implementation stage. At present, many more popular software systems such as Gnutella, Freenet, Napster are deployed based on P2P technology. How to achieve effective information query has become one of the key problems of P2P research.

  19. Improved personalized recommendation based on a similarity network

    NASA Astrophysics Data System (ADS)

    Wang, Ximeng; Liu, Yun; Xiong, Fei

    2016-08-01

    A recommender system helps individual users find the preferred items rapidly and has attracted extensive attention in recent years. Many successful recommendation algorithms are designed on bipartite networks, such as network-based inference or heat conduction. However, most of these algorithms define the resource-allocation methods for an average allocation. That is not reasonable because average allocation cannot indicate the user choice preference and the influence between users which leads to a series of non-personalized recommendation results. We propose a personalized recommendation approach that combines the similarity function and bipartite network to generate a similarity network that improves the resource-allocation process. Our model introduces user influence into the recommender system and states that the user influence can make the resource-allocation process more reasonable. We use four different metrics to evaluate our algorithms for three benchmark data sets. Experimental results show that the improved recommendation on a similarity network can obtain better accuracy and diversity than some competing approaches.

  20. 3-D target-based distributed smart camera network localization.

    PubMed

    Kassebaum, John; Bulusu, Nirupama; Feng, Wu-Chi

    2010-10-01

    For distributed smart camera networks to perform vision-based tasks such as subject recognition and tracking, every camera's position and orientation relative to a single 3-D coordinate frame must be accurately determined. In this paper, we present a new camera network localization solution that requires successively showing a 3-D feature point-rich target to all cameras, then using the known geometry of a 3-D target, cameras estimate and decompose projection matrices to compute their position and orientation relative to the coordinatization of the 3-D target's feature points. As each 3-D target position establishes a distinct coordinate frame, cameras that view more than one 3-D target position compute translations and rotations relating different positions' coordinate frames and share the transform data with neighbors to facilitate realignment of all cameras to a single coordinate frame. Compared to other localization solutions that use opportunistically found visual data, our solution is more suitable to battery-powered, processing-constrained camera networks because it requires communication only to determine simultaneous target viewings and for passing transform data. Additionally, our solution requires only pairwise view overlaps of sufficient size to see the 3-D target and detect its feature points, while also giving camera positions in meaningful units. We evaluate our algorithm in both real and simulated smart camera networks. In the real network, position error is less than 1 ('') when the 3-D target's feature points fill only 2.9% of the frame area. PMID:20679031

  1. Prolonging the lifetime of wireless sensor networks interconnected to fixed network using hierarchical energy tree based routing algorithm.

    PubMed

    Kalpana, M; Dhanalakshmi, R; Parthiban, P

    2014-01-01

    This research work proposes a mathematical model for the lifetime of wireless sensor networks (WSN). It also proposes an energy efficient routing algorithm for WSN called hierarchical energy tree based routing algorithm (HETRA) based on hierarchical energy tree constructed using the available energy in each node. The energy efficiency is further augmented by reducing the packet drops using exponential congestion control algorithm (TCP/EXP). The algorithms are evaluated in WSNs interconnected to fixed network with seven distribution patterns, simulated in ns2 and compared with the existing algorithms based on the parameters such as number of data packets, throughput, network lifetime, and data packets average network lifetime product. Evaluation and simulation results show that the combination of HETRA and TCP/EXP maximizes longer network lifetime in all the patterns. The lifetime of the network with HETRA algorithm has increased approximately 3.2 times that of the network implemented with AODV. PMID:25535626

  2. Prolonging the Lifetime of Wireless Sensor Networks Interconnected to Fixed Network Using Hierarchical Energy Tree Based Routing Algorithm

    PubMed Central

    Kalpana, M.; Dhanalakshmi, R.; Parthiban, P.

    2014-01-01

    This research work proposes a mathematical model for the lifetime of wireless sensor networks (WSN). It also proposes an energy efficient routing algorithm for WSN called hierarchical energy tree based routing algorithm (HETRA) based on hierarchical energy tree constructed using the available energy in each node. The energy efficiency is further augmented by reducing the packet drops using exponential congestion control algorithm (TCP/EXP). The algorithms are evaluated in WSNs interconnected to fixed network with seven distribution patterns, simulated in ns2 and compared with the existing algorithms based on the parameters such as number of data packets, throughput, network lifetime, and data packets average network lifetime product. Evaluation and simulation results show that the combination of HETRA and TCP/EXP maximizes longer network lifetime in all the patterns. The lifetime of the network with HETRA algorithm has increased approximately 3.2 times that of the network implemented with AODV. PMID:25535626

  3. Effects of stream topology on ecological community results from neutral models

    EPA Science Inventory

    While neutral theory and models have stimulated considerable literature, less well investigated is the effect of topology on neutral metacommunity model simulations. We implemented a neutral metacommunity model using two different stream network topologies, a widely branched netw...

  4. Wet Channel Network Extraction based on LiDAR Data

    NASA Astrophysics Data System (ADS)

    Hooshyar, M.; Kim, S.; Wang, D.; Medeiros, S. C.

    2015-12-01

    The temporal dynamics of stream network is vitally important for understanding hydrologic processes including groundwater interactions and hydrograph recessions. However, observations are limited on flowing channel heads, which are usually located in headwater catchments and under canopy. Near infrared LiDAR data provides an opportunity to map the flowing channel network owing to the fine spatial resolution, canopy penetration, and strong absorption of the light energy by the water surface. A systematic method is developed herein to map flowing channel networks based on the signal intensity of ground LiDAR return, which is lower on water surfaces than on dry surfaces. Based on the selected sample sites where the wetness conditions are known, the signal intensities of ground returns are extracted from the LiDAR point data. The frequency distributions of wet surface and dry surface returns are constructed. With the aid of LiDAR-based ground elevation, the signal intensity thresholds are identified for mapping flowing channels. The developed method is applied to Lake Tahoe area based on eight LiDAR snapshots during recession periods in five watersheds. A power-law relationship between streamflow and flowing channel length during the recession period is derived based on the result.

  5. Building SDN-Based Agricultural Vehicular Sensor Networks Based on Extended Open vSwitch.

    PubMed

    Huang, Tao; Yan, Siyu; Yang, Fan; Pan, Tian; Liu, Jiang

    2016-01-01

    Software-defined vehicular sensor networks in agriculture, such as autonomous vehicle navigation based on wireless multi-sensor networks, can lead to more efficient precision agriculture. In SDN-based vehicle sensor networks, the data plane is simplified and becomes more efficient by introducing a centralized controller. However, in a wireless environment, the main controller node may leave the sensor network due to the dynamic topology change or the unstable wireless signal, leaving the rest of network devices without control, e.g., a sensor node as a switch may forward packets according to stale rules until the controller updates the flow table entries. To solve this problem, this paper proposes a novel SDN-based vehicular sensor networks architecture which can minimize the performance penalty of controller connection loss. We achieve this by designing a connection state detection and self-learning mechanism. We build prototypes based on extended Open vSwitch and Ryu. The experimental results show that the recovery time from controller connection loss is under 100 ms and it keeps rule updating in real time with a stable throughput. This architecture enhances the survivability and stability of SDN-based vehicular sensor networks in precision agriculture. PMID:26797616

  6. Building SDN-Based Agricultural Vehicular Sensor Networks Based on Extended Open vSwitch

    PubMed Central

    Huang, Tao; Yan, Siyu; Yang, Fan; Pan, Tian; Liu, Jiang

    2016-01-01

    Software-defined vehicular sensor networks in agriculture, such as autonomous vehicle navigation based on wireless multi-sensor networks, can lead to more efficient precision agriculture. In SDN-based vehicle sensor networks, the data plane is simplified and becomes more efficient by introducing a centralized controller. However, in a wireless environment, the main controller node may leave the sensor network due to the dynamic topology change or the unstable wireless signal, leaving the rest of network devices without control, e.g., a sensor node as a switch may forward packets according to stale rules until the controller updates the flow table entries. To solve this problem, this paper proposes a novel SDN-based vehicular sensor networks architecture which can minimize the performance penalty of controller connection loss. We achieve this by designing a connection state detection and self-learning mechanism. We build prototypes based on extended Open vSwitch and Ryu. The experimental results show that the recovery time from controller connection loss is under 100 ms and it keeps rule updating in real time with a stable throughput. This architecture enhances the survivability and stability of SDN-based vehicular sensor networks in precision agriculture. PMID:26797616

  7. Neural networks application to divergence-based passive ranging

    NASA Technical Reports Server (NTRS)

    Barniv, Yair

    1992-01-01

    The purpose of this report is to summarize the state of knowledge and outline the planned work in divergence-based/neural networks approach to the problem of passive ranging derived from optical flow. Work in this and closely related areas is reviewed in order to provide the necessary background for further developments. New ideas about devising a monocular passive-ranging system are then introduced. It is shown that image-plan divergence is independent of image-plan location with respect to the focus of expansion and of camera maneuvers because it directly measures the object's expansion which, in turn, is related to the time-to-collision. Thus, a divergence-based method has the potential of providing a reliable range complementing other monocular passive-ranging methods which encounter difficulties in image areas close to the focus of expansion. Image-plan divergence can be thought of as some spatial/temporal pattern. A neural network realization was chosen for this task because neural networks have generally performed well in various other pattern recognition applications. The main goal of this work is to teach a neural network to derive the divergence from the imagery.

  8. Block-Based Neural Networks with Pulsed Neuron Model

    NASA Astrophysics Data System (ADS)

    Iguchi, Syota; Koakutsu, Seiichi; Okamoto, Takashi; Hirata, Hironori

    In recent years, the study of hardware implementation of Neural Networks (NN) has been getting more important. In particular, Block-Based Neural Networks (BBNN) which are one of NN have been attracted attention. However, the conventional BBNN are analogue NN (ANN). The digital hardware implementation of ANN is very difficult, because the input and output signals are represented as analogue values. Pulsed Neural Networks (PNN) which adopt a pulsed neuron (PN) model instead of the AN model have been proposed in order to solve this problem. The input and output signals of PNN are represented as a series of pulses, and thus the digital hardware implementation of PNN becomes easy. In this paper, we propose Block-Based Pulsed Neural Networks (BBPNN) introducing the PN model into BBNN in order to faciliate the implementation of NN on digital hardware. We use particle swarm optimization (PSO) for optimization of weights of BBPNN, because PSO can produce a globally optimum solution of nonlinear continuous optimization problems in practicable calculation time by high accuracy. To evaluate the proposed BBPNN, we apply them to XOR problem and autonomous mobile robot control problems. Computational experiments indicate that the proposed BBPNN and the conventional BBNN can produce about the same results.

  9. The optimal community detection of software based on complex networks

    NASA Astrophysics Data System (ADS)

    Huang, Guoyan; Zhang, Peng; Zhang, Bing; Yin, Tengteng; Ren, Jiadong

    2016-02-01

    The community structure is important for software in terms of understanding the design patterns, controlling the development and the maintenance process. In order to detect the optimal community structure in the software network, a method Optimal Partition Software Network (OPSN) is proposed based on the dependency relationship among the software functions. First, by analyzing the information of multiple execution traces of one software, we construct Software Execution Dependency Network (SEDN). Second, based on the relationship among the function nodes in the network, we define Fault Accumulation (FA) to measure the importance of the function node and sort the nodes with measure results. Third, we select the top K(K=1,2,…) nodes as the core of the primal communities (only exist one core node). By comparing the dependency relationships between each node and the K communities, we put the node into the existing community which has the most close relationship. Finally, we calculate the modularity with different initial K to obtain the optimal division. With experiments, the method OPSN is verified to be efficient to detect the optimal community in various softwares.

  10. In silico network topology-based prediction of gene essentiality

    NASA Astrophysics Data System (ADS)

    da Silva, João Paulo Müller; Acencio, Marcio Luis; Mombach, José Carlos Merino; Vieira, Renata; da Silva, José Camargo; Lemke, Ney; Sinigaglia, Marialva

    2008-02-01

    The identification of genes essential for survival is important for the understanding of the minimal requirements for cellular life and for drug design. As experimental studies with the purpose of building a catalog of essential genes for a given organism are time-consuming and laborious, a computational approach which could predict gene essentiality with high accuracy would be of great value. We present here a novel computational approach, called NTPGE (Network Topology-based Prediction of Gene Essentiality), that relies on the network topology features of a gene to estimate its essentiality. The first step of NTPGE is to construct the integrated molecular network for a given organism comprising protein physical, metabolic and transcriptional regulation interactions. The second step consists in training a decision-tree-based machine-learning algorithm on known essential and non-essential genes of the organism of interest, considering as learning attributes the network topology information for each of these genes. Finally, the decision-tree classifier generated is applied to the set of genes of this organism to estimate essentiality for each gene. We applied the NTPGE approach for discovering the essential genes in Escherichia coli and then assessed its performance.

  11. Implementation of medical monitor system based on networks

    NASA Astrophysics Data System (ADS)

    Yu, Hui; Cao, Yuzhen; Zhang, Lixin; Ding, Mingshi

    2006-11-01

    In this paper, the development trend of medical monitor system is analyzed and portable trend and network function become more and more popular among all kinds of medical monitor devices. The architecture of medical network monitor system solution is provided and design and implementation details of medical monitor terminal, monitor center software, distributed medical database and two kind of medical information terminal are especially discussed. Rabbit3000 system is used in medical monitor terminal to implement security administration of data transfer on network, human-machine interface, power management and DSP interface while DSP chip TMS5402 is used in signal analysis and data compression. Distributed medical database is designed for hospital center according to DICOM information model and HL7 standard. Pocket medical information terminal based on ARM9 embedded platform is also developed to interactive with center database on networks. Two kernels based on WINCE are customized and corresponding terminal software are developed for nurse's routine care and doctor's auxiliary diagnosis. Now invention patent of the monitor terminal is approved and manufacture and clinic test plans are scheduled. Applications for invention patent are also arranged for two medical information terminals.

  12. Real-time EFIT data reconstruction based on neural network in KSTAR

    NASA Astrophysics Data System (ADS)

    Kwak, Sehyun; Jeon, Youngmu; Ghim, Young-Chul

    2014-10-01

    Real-time EFIT data can be obtained using a neural network method. A non-linear mapping between diagnostic signals and shaping parameters of plasma equilibrium can be established by the neural network, particularly with the multilayer perceptron. The neural network is utilized to attain real-time EFIT data for Korea Superconducting Tokamak for Advanced Research (KSTAR). We collect and process existing datasets of measured data and EFIT data to train and test the neural network. Parameter scans such as the numbers of hidden layers and hidden units were performed in order to find the optimal condition. EFIT data from the neural network was compared with both offline EFIT and real-time EFIT data. Finally, we discuss advantages of using neutral network reconstructed EFIT data for real time plasma control.

  13. Price-Based Information Routing in Complex Satellite Networks for

    NASA Astrophysics Data System (ADS)

    Hussein, I.; Su, J.; Wang, Y.; Wyglinski, A.

    Future space-based situational awareness and space surveillance systems are envisioned to include a large array of satellites that seek to cooperatively achieve full awareness over given space and terrestrial domains. Given the complexity of the communication network architecture of such a system, in this paper we build on the system architecture that was proposed by the presenting author in the 2008 AMOS conference and propose an efficient, adaptable and scalable price-based routing and bandwidth allocation algorithm for the generation, routing and delivery of surveillance information in distributed wireless satellite networks. Due to the potentially large deployments of these satellites, the access points employed in a centralized network control scheme would easily be overwhelmed due to lack of spectral bandwidth, synchronization issues, and multiple access coordination. Alternatively, decentralized schemes could facilitate the flow and transference of information between data gatherers and data collectors via mechanisms such as (multi-hop) routing, allocation of spectral bandwidths per relaying node, and coordination between adjacent nodes. Although there are numerous techniques and concepts focusing on the network operations, control, and management of sensor networks, existing solution approaches require the use of information for routing, allocation, and decision-making that may not be readily available to the satellites in a timely fashion. This is especially true in the literature on price-based routing, where the approach is almost always game theoretic or relies on optimization techniques. Instead of seeking such techniques, in this paper we present algorithms that will (1) be energy-aware, (2) be highly adaptable and responsive to demands and seek delivery of information to desired nodes despite the fact that the source and destination are not globally known, (3) be secure, (4) be efficient in allocating bandwidth, (5) be decentralized and allow for

  14. Adaptive NUC algorithm for uncooled IRFPA based on neural networks

    NASA Astrophysics Data System (ADS)

    Liu, Ziji; Jiang, Yadong; Lv, Jian; Zhu, Hongbin

    2010-10-01

    With developments in uncooled infrared plane array (UFPA) technology, many new advanced uncooled infrared sensors are used in defensive weapons, scientific research, industry and commercial applications. A major difference in imaging techniques between infrared IRFPA imaging system and a visible CCD camera is that, IRFPA need nonuniformity correction and dead pixel compensation, we usually called it infrared image pre-processing. Two-point or multi-point correction algorithms based on calibration commonly used may correct the non-uniformity of IRFPAs, but they are limited by pixel linearity and instability. Therefore, adaptive non-uniformity correction techniques are developed. Two of these adaptive non-uniformity correction algorithms are mostly discussed, one is based on temporal high-pass filter, and another is based on neural network. In this paper, a new NUC algorithm based on improved neural networks is introduced, and involves the compare result between improved neural networks and other adaptive correction techniques. A lot of different will discussed in different angle, like correction effects, calculation efficiency, hardware implementation and so on. According to the result and discussion, it could be concluding that the adaptive algorithm offers improved performance compared to traditional calibration mode techniques. This new algorithm not only provides better sensitivity, but also increases the system dynamic range. As the sensor application expended, it will be very useful in future infrared imaging systems.

  15. Ordinal regression neural networks based on concentric hyperspheres.

    PubMed

    Gutiérrez, Pedro Antonio; Tiňo, Peter; Hervás-Martínez, César

    2014-11-01

    Threshold models are one of the most common approaches for ordinal regression, based on projecting patterns to the real line and dividing this real line in consecutive intervals, one interval for each class. However, finding such one-dimensional projection can be too harsh an imposition for some datasets. This paper proposes a multidimensional latent space representation with the purpose of relaxing this projection, where the different classes are arranged based on concentric hyperspheres, each class containing the previous classes in the ordinal scale. The proposal is implemented through a neural network model, each dimension being a linear combination of a common set of basis functions. The model is compared to a nominal neural network, a neural network based on the proportional odds model and to other state-of-the-art ordinal regression methods for a total of 12 datasets. The proposed latent space shows an improvement on the two performance metrics considered, and the model based on the three-dimensional latent space obtains competitive performance when compared to the other methods. PMID:25078110

  16. Feature Selection for Neural Network Based Stock Prediction

    NASA Astrophysics Data System (ADS)

    Sugunnasil, Prompong; Somhom, Samerkae

    We propose a new methodology of feature selection for stock movement prediction. The methodology is based upon finding those features which minimize the correlation relation function. We first produce all the combination of feature and evaluate each of them by using our evaluate function. We search through the generated set with hill climbing approach. The self-organizing map based stock prediction model is utilized as the prediction method. We conduct the experiment on data sets of the Microsoft Corporation, General Electric Co. and Ford Motor Co. The results show that our feature selection method can improve the efficiency of the neural network based stock prediction.

  17. Profile-based adaptive anomaly detection for network security.

    SciTech Connect

    Zhang, Pengchu C. (Sandia National Laboratories, Albuquerque, NM); Durgin, Nancy Ann

    2005-11-01

    As information systems become increasingly complex and pervasive, they become inextricably intertwined with the critical infrastructure of national, public, and private organizations. The problem of recognizing and evaluating threats against these complex, heterogeneous networks of cyber and physical components is a difficult one, yet a solution is vital to ensuring security. In this paper we investigate profile-based anomaly detection techniques that can be used to address this problem. We focus primarily on the area of network anomaly detection, but the approach could be extended to other problem domains. We investigate using several data analysis techniques to create profiles of network hosts and perform anomaly detection using those profiles. The ''profiles'' reduce multi-dimensional vectors representing ''normal behavior'' into fewer dimensions, thus allowing pattern and cluster discovery. New events are compared against the profiles, producing a quantitative measure of how ''anomalous'' the event is. Most network intrusion detection systems (IDSs) detect malicious behavior by searching for known patterns in the network traffic. This approach suffers from several weaknesses, including a lack of generalizability, an inability to detect stealthy or novel attacks, and lack of flexibility regarding alarm thresholds. Our research focuses on enhancing current IDS capabilities by addressing some of these shortcomings. We identify and evaluate promising techniques for data mining and machine-learning. The algorithms are ''trained'' by providing them with a series of data-points from ''normal'' network traffic. A successful algorithm can be trained automatically and efficiently, will have a low error rate (low false alarm and miss rates), and will be able to identify anomalies in ''pseudo real-time'' (i.e., while the intrusion is still in progress, rather than after the fact). We also build a prototype anomaly detection tool that demonstrates how the techniques might

  18. Testbed for ROADM and WXC Based Metro WDM Networks

    NASA Astrophysics Data System (ADS)

    Zong, Lei; Ji, Philip; Xu, Lei; Wang, Ting; Matsuda, Osamu; Cvijetic, Milorad

    2005-11-01

    A testbed for metro wavelength division multiplexing (WDM) network is realized and tested. The testbed contains a reconfigurable optical add/drop multiplexer (ROADM) node, a 2x2 wavelength cross-connect (WXC) node, and two interconnected two-fiber bidirectional path protected switching ring networks (TF-BPSR). Both the ROADM and WXC node are bidirectional nodes, so they can select channels from the working and the protection ring networks simultaneously, and they support both protected and unprotected services. The ROADM node uses a flexible band tunable filter (FBTF) to drop a waveband from the input WDM signals and send the express channels directly to the output port. As a result, the physical impairment accumulated on the express channels can be minimized. It also has a modular structure, so additional modules can be cascaded to expand the capacity and functionality of the node without any interruption to current services. The WXC node is realized with interconnected ROADM modules that are comprised of wavelength selective switches (WSSes). Arbitrary wavelength or wavelength sets can be either dropped in the node or cross-connected in a non-blocking manner. Multiple services, such as OC-48 and OC-192 SONET signals, gigabit Ethernet streams carrying interactive movie signals, and live video broadcasting services, are carried in the network, dropped in the ROADM and WXC node, and switched between the two ring networks. The testbed is controlled by a websever based network management system that facilitates remote control and monitoring. Experiments demonstrate that the performance of the nodes and the testbed meets the requirement of the services.

  19. A network-base analysis of CMIP5 "historical" experiments

    NASA Astrophysics Data System (ADS)

    Bracco, A.; Foudalis, I.; Dovrolis, C.

    2012-12-01

    In computer science, "complex network analysis" refers to a set of metrics, modeling tools and algorithms commonly used in the study of complex nonlinear dynamical systems. Its main premise is that the underlying topology or network structure of a system has a strong impact on its dynamics and evolution. By allowing to investigate local and non-local statistical interaction, network analysis provides a powerful, but only marginally explored, framework to validate climate models and investigate teleconnections, assessing their strength, range, and impacts on the climate system. In this work we propose a new, fast, robust and scalable methodology to examine, quantify, and visualize climate sensitivity, while constraining general circulation models (GCMs) outputs with observations. The goal of our novel approach is to uncover relations in the climate system that are not (or not fully) captured by more traditional methodologies used in climate science and often adopted from nonlinear dynamical systems analysis, and to explain known climate phenomena in terms of the network structure or its metrics. Our methodology is based on a solid theoretical framework and employs mathematical and statistical tools, exploited only tentatively in climate research so far. Suitably adapted to the climate problem, these tools can assist in visualizing the trade-offs in representing global links and teleconnections among different data sets. Here we present the methodology, and compare network properties for different reanalysis data sets and a suite of CMIP5 coupled GCM outputs. With an extensive model intercomparison in terms of the climate network that each model leads to, we quantify how each model reproduces major teleconnections, rank model performances, and identify common or specific errors in comparing model outputs and observations.

  20. A new balancing three level three dimensional space vector modulation strategy for three level neutral point clamped four leg inverter based shunt active power filter controlling by nonlinear back stepping controllers.

    PubMed

    Chebabhi, Ali; Fellah, Mohammed Karim; Kessal, Abdelhalim; Benkhoris, Mohamed F

    2016-07-01

    In this paper is proposed a new balancing three-level three dimensional space vector modulation (B3L-3DSVM) strategy which uses a redundant voltage vectors to realize precise control and high-performance for a three phase three-level four-leg neutral point clamped (NPC) inverter based Shunt Active Power Filter (SAPF) for eliminate the source currents harmonics, reduce the magnitude of neutral wire current (eliminate the zero-sequence current produced by single-phase nonlinear loads), and to compensate the reactive power in the three-phase four-wire electrical networks. This strategy is proposed in order to gate switching pulses generation, dc bus voltage capacitors balancing (conserve equal voltage of the two dc bus capacitors), and to switching frequency reduced and fixed of inverter switches in same times. A Nonlinear Back Stepping Controllers (NBSC) are used for regulated the dc bus voltage capacitors and the SAPF injected currents to robustness, stabilizing the system and to improve the response and to eliminate the overshoot and undershoot of traditional PI (Proportional-Integral). Conventional three-level three dimensional space vector modulation (C3L-3DSVM) and B3L-3DSVM are calculated and compared in terms of error between the two dc bus voltage capacitors, SAPF output voltages and THDv, THDi of source currents, magnitude of source neutral wire current, and the reactive power compensation under unbalanced single phase nonlinear loads. The success, robustness, and the effectiveness of the proposed control strategies are demonstrated through simulation using Sim Power Systems and S-Function of MATLAB/SIMULINK. PMID:27018144

  1. Hybrid scheduling mechanisms for Next-generation Passive Optical Networks based on network coding

    NASA Astrophysics Data System (ADS)

    Zhao, Jijun; Bai, Wei; Liu, Xin; Feng, Nan; Maier, Martin

    2014-10-01

    Network coding (NC) integrated into Passive Optical Networks (PONs) is regarded as a promising solution to achieve higher throughput and energy efficiency. To efficiently support multimedia traffic under this new transmission mode, novel NC-based hybrid scheduling mechanisms for Next-generation PONs (NG-PONs) including energy management, time slot management, resource allocation, and Quality-of-Service (QoS) scheduling are proposed in this paper. First, we design an energy-saving scheme that is based on Bidirectional Centric Scheduling (BCS) to reduce the energy consumption of both the Optical Line Terminal (OLT) and Optical Network Units (ONUs). Next, we propose an intra-ONU scheduling and an inter-ONU scheduling scheme, which takes NC into account to support service differentiation and QoS assurance. The presented simulation results show that BCS achieves higher energy efficiency under low traffic loads, clearly outperforming the alternative NC-based Upstream Centric Scheduling (UCS) scheme. Furthermore, BCS is shown to provide better QoS assurance.

  2. Neutral atom traps.

    SciTech Connect

    Pack, Michael Vern

    2008-12-01

    This report describes progress in designing a neutral atom trap capable of trapping sub millikelvin atom in a magnetic trap and shuttling the atoms across the atom chip from a collection area to an optical cavity. The numerical simulation and atom chip design are discussed. Also, discussed are preliminary calculations of quantum noise sources in Kerr nonlinear optics measurements based on electromagnetically induced transparency. These types of measurements may be important for quantum nondemolition measurements at the few photon limit.

  3. Modeling thermospheric neutral density

    NASA Astrophysics Data System (ADS)

    Qian, Liying

    Satellite drag prediction requires determination of thermospheric neutral density. The NCAR Thermosphere-Ionosphere-Electrodynamics General Circulation Model (TIEGCM) and the global-mean Thermosphere-Ionosphere-Mesosphere-Electrodynamics General Circulation Model (TIMEGCM) were used to quantify thermospheric neutral density and its variations, focusing on annual/semiannual variation, the effect of using measured solar irradiance on model calculations of solar-cycle variation, and global change in the thermosphere. Satellite drag data and the MSIS00 empirical model were utilized to compare to the TIEGCM simulations. The TIEGCM simulations indicated that eddy diffusion and its annual/semiannual variation is a mechanism for annual/semiannual density variation in the thermosphere. It was found that eddy diffusion near the turbopause can effectively influence thermospheric neutral density. Eddy diffusion, together with annual insolation variation and large-scale circulation, generated global annual/semiannual density variation observed by satellite drag. Using measured solar irradiance as solar input for the TIEGCM improved the solar-cycle dependency of the density calculation shown in F10.7 -based thermospheric empirical models. It has been found that the empirical models overestimate density at low solar activity. The TIEGCM simulations did not show such solar-cycle dependency. Using historic measurements of CO2 and F 10.7, simulations of the global-mean TIMEGCM showed that thermospheric neutral density at 400 km had an average long-term decrease of 1.7% per decade from 1970 to 2000. A forecast of density decrease for solar cycle 24 suggested that thermospheric density will decrease at 400 km from present to the end of solar cycle 24 at a rate of 2.7% per decade. Reduction in thermospheric density causes less atmospheric drag on earth-orbiting space objects. The implication of this long-term decrease of thermospheric neutral density is that it will increase the

  4. Refinement of the background ionospheric conditions and plausible explanation based on neutral dynamics for the occurrence/non-occurrence of L-band scintillation patches against forecast.

    NASA Astrophysics Data System (ADS)

    Sridharan, R.; Jose, Lijo; Bagiya, Mala S.; Sunda, Surendra; Chaudhary, R. K.; Pant, Tarun K.

    2015-10-01

    The recently evolved L-band scintillation forecast mechanism based on the characteristic features of the daytime F-region electron density fluctuations and also on the basic ionospheric conditions had been successful to a reasonable extent in forecasting the spatio-temporal map of scintillation patches. There had been a few non-compliances in the expected pattern within/outside the forecast windows. The present paper attempts to address such non-compliances and offers a plausible explanation based on neutral dynamics, especially the local time variation of vertical winds over the magnetic equator, while at the same time refining the earlier stipulated background ionospheric conditions. With the above refinements, it is anticipated that the forecast mechanism would become very robust. The present results highlight the importance of the neutral dynamical parameters and the urgent need to concentrate on the efforts to make systematic measurements of the same in order to characterize their variability.

  5. Destabilization of ellipticity-induced Alfvén eigenmodes during ICRF heating and stabilization by negative-ion-based neutral beam injection in JT-60U

    NASA Astrophysics Data System (ADS)

    Kusama, Y.; Fu, G. Y.; Kramer, G. J.; Saigusa, M.; Oikawa, T.; Ozeki, T.; Moriyama, S.; Tchernychev, F. V.; Nemoto, M.; Kondoh, T.; Hatae, T.; Tobita, K.; Kuriyama, M.; Cheng, C. Z.; Kimura, H.

    1999-09-01

    High-frequency modes in the 525-550 kHz range with toroidal mode numbers n = 3-7 were excited after the sawtooth crash during ion cyclotron range of frequency (ICRF) heating. Based on the stability analysis using the NOVA-K code, these modes were found to be consistent with ellipticity-induced Alfvén eigenmodes (EAEs) excited in the EAE gap located at the q = 1 surface. A change in the safety factor after the sawtooth crash was essential for the excitation of EAEs in the core region of the plasma. The high-frequency modes were stabilized by the neutral beam injection at 350 keV using negative-ion-based neutral beam (NNB) injectors. Stability analysis using the NOVA-K code has shown that NNB-injected ions enhance the damping of the EAEs and tend to stabilize them.

  6. Automated neural network-based instrument validation system

    NASA Astrophysics Data System (ADS)

    Xu, Xiao

    2000-10-01

    In a complex control process, instrument calibration is periodically performed to maintain the instruments within the calibration range, which assures proper control and minimizes down time. Instruments are usually calibrated under out-of-service conditions using manual calibration methods, which may cause incorrect calibration or equipment damage. Continuous in-service calibration monitoring of sensors and instruments will reduce unnecessary instrument calibrations, give operators more confidence in instrument measurements, increase plant efficiency or product quality, and minimize the possibility of equipment damage during unnecessary manual calibrations. In this dissertation, an artificial neural network (ANN)-based instrument calibration verification system is designed to achieve the on-line monitoring and verification goal for scheduling maintenance. Since an ANN is a data-driven model, it can learn the relationships among signals without prior knowledge of the physical model or process, which is usually difficult to establish for the complex non-linear systems. Furthermore, the ANNs provide a noise-reduced estimate of the signal measurement. More importantly, since a neural network learns the relationships among signals, it can give an unfaulted estimate of a faulty signal based on information provided by other unfaulted signals; that is, provide a correct estimate of a faulty signal. This ANN-based instrument verification system is capable of detecting small degradations or drifts occurring in instrumentation, and preclude false control actions or system damage caused by instrument degradation. In this dissertation, an automated scheme of neural network construction is developed. Previously, the neural network structure design required extensive knowledge of neural networks. An automated design methodology was developed so that a network structure can be created without expert interaction. This validation system was designed to monitor process sensors plant

  7. Security management based on trust determination in cognitive radio networks

    NASA Astrophysics Data System (ADS)

    Li, Jianwu; Feng, Zebing; Wei, Zhiqing; Feng, Zhiyong; Zhang, Ping

    2014-12-01

    Security has played a major role in cognitive radio networks. Numerous researches have mainly focused on attacking detection based on source localization and detection probability. However, few of them took the penalty of attackers into consideration and neglected how to implement effective punitive measures against attackers. To address this issue, this article proposes a novel penalty mechanism based on cognitive trust value. The main feature of this mechanism has been realized by six functions: authentication, interactive, configuration, trust value collection, storage and update, and punishment. Data fusion center (FC) and cluster heads (CHs) have been put forward as a hierarchical architecture to manage trust value of cognitive users. Misbehaving users would be punished by FC by declining their trust value; thus, guaranteeing network security via distinguishing attack users is of great necessity. Simulation results verify the rationality and effectiveness of our proposed mechanism.

  8. Circular sensing networks for guided waves based structural health monitoring

    NASA Astrophysics Data System (ADS)

    Wandowski, T.; Malinowski, P. H.; Ostachowicz, W. M.

    2016-01-01

    In this paper, results of damage localization performed for four sensing network configurations are compared. Process of damage localization is based on guided waves propagation phenomenon. Guided waves are excited using piezoelectric transducer and received by scanning laser vibrometer. Different excitation frequencies are also investigated. In experimental investigations two types of piezoelectric transducers are used as guided waves exciters. Frequency-magnitude characteristics of symmetric and antisymmetric modes are created for both types of transducers. These characteristics allow a choice of an excitation frequency for efficient generation of selected wave mode. The amplitude of second mode in this case has negligibly small value. Finally, sensing networks in the form of circle with three different diameters are realized based on piezoelectric transducers. Damage localization algorithm is prepared in MATLAB® environment as well as in C++.

  9. Standards-Based Wireless Sensor Networking Protocols for Spaceflight Applications

    NASA Technical Reports Server (NTRS)

    Wagner, Raymond S.

    2010-01-01

    Wireless sensor networks (WSNs) have the capacity to revolutionize data gathering in both spaceflight and terrestrial applications. WSNs provide a huge advantage over traditional, wired instrumentation since they do not require wiring trunks to connect sensors to a central hub. This allows for easy sensor installation in hard to reach locations, easy expansion of the number of sensors or sensing modalities, and reduction in both system cost and weight. While this technology offers unprecedented flexibility and adaptability, implementing it in practice is not without its difficulties. Recent advances in standards-based WSN protocols for industrial control applications have come a long way to solving many of the challenges facing practical WSN deployments. In this paper, we will overview two of the more promising candidates - WirelessHART from the HART Communication Foundation and ISA100.11a from the International Society of Automation - and present the architecture for a new standards-based sensor node for networking and applications research.

  10. Performance evaluation of cellular phone network based portable ECG device.

    PubMed

    Hong, Joo-Hyun; Cha, Eun-Jong; Lee, Tae-Soo

    2008-01-01

    In this study, cellular phone network based portable ECG device was developed and three experiments were performed to evaluate the accuracy, reliability and operability, applicability during daily life of the developed device. First, ECG signals were measured using the developed device and Biopac device (reference device) during sitting and marking time and compared to verify the accuracy of R-R intervals. Second, the reliable data transmission to remote server was verified on two types of simulated emergency event using patient simulator. Third, during daily life with five types of motion, accuracy of data transmission to remote server was verified on two types of event occurring. By acquiring and comparing subject's biomedical signal and motion signal, the accuracy, reliability and operability, applicability during daily life of the developed device were verified. Therefore, cellular phone network based portable ECG device can monitor patient with inobtrusive manner. PMID:19162767

  11. Highly spectral efficient networks based on grouped optical path routing.

    PubMed

    Terada, Yuki; Mori, Yojiro; Hasegawa, Hiroshi; Sato, Ken-Ichi

    2016-03-21

    In order to mitigate the signal spectrum narrowing caused by optical filtering at nodes, an adequate guard band is needed between optical channels, which degrades the frequency utilization of optical fibers. In this study, we propose a grouped routing based network architecture that minimizes spectrum narrowing while greatly improving spectral efficiency. Coarse granular routing at GRE (grouped routing entity) level is employed at each ROADM node, but fine granular add/drop is adopted to retain high frequency utilization. Optical channels are packed densely in each GRE, and sufficient guard bands are inserted between GREs. As a result, signal spectrum narrowing is minimized and efficient spectrum utilization is achieved. Network design/control algorithms that support both static and dynamic traffic growth are developed. Extensive simulations demonstrate the effectiveness of the proposed architecture. To implement the scheme, current LCOS-based ROADMs are applied without any hardware changes; only the control schema are modified. PMID:27136815

  12. Network Capacity Assessment of CHP-based Distributed Generation on Urban Energy Distribution Networks

    NASA Astrophysics Data System (ADS)

    Zhang, Xianjun

    The combined heat and power (CHP)-based distributed generation (DG) or dis-tributed energy resources (DERs) are mature options available in the present energy market, considered to be an effective solution to promote energy efficiency. In the urban environment, the electricity, water and natural gas distribution networks are becoming increasingly interconnected with the growing penetration of the CHP-based DG. Subsequently, this emerging interdependence leads to new topics meriting serious consideration: how much of the CHP-based DG can be accommodated and where to locate these DERs, and given preexisting constraints, how to quantify the mutual impacts on operation performances between these urban energy distribution networks and the CHP-based DG. The early research work was conducted to investigate the feasibility and design methods for one residential microgrid system based on existing electricity, water and gas infrastructures of a residential community, mainly focusing on the economic planning. However, this proposed design method cannot determine the optimal DG sizing and siting for a larger test bed with the given information of energy infrastructures. In this context, a more systematic as well as generalized approach should be developed to solve these problems. In the later study, the model architecture that integrates urban electricity, water and gas distribution networks, and the CHP-based DG system was developed. The proposed approach addressed the challenge of identifying the optimal sizing and siting of the CHP-based DG on these urban energy networks and the mutual impacts on operation performances were also quantified. For this study, the overall objective is to maximize the electrical output and recovered thermal output of the CHP-based DG units. The electricity, gas, and water system models were developed individually and coupled by the developed CHP-based DG system model. The resultant integrated system model is used to constrain the DG's electrical

  13. Development of a cell-based qualitative assay for detection of neutralizing anti-human interleukin-1 receptor antagonist (hIL-1Ra) antibodies in rats.

    PubMed

    Gao, Jin; Li, Jingjing; Yang, Minmin; Wu, Mingyuan; Tu, Ping; Yu, Yan; Han, Wei

    2015-01-01

    To determine the incidence of the positive neutralizing anti-human interleukin receptor antagonist (anti-IL-1Ra), a novel assay based on the proliferation of human melanoma A375.S2 cells was developed and validated. In the presence of a growth-limiting concentration of IL-1β, A375.S2 cells were able to regain proliferation following the addition of IL-1Ra in a concentration-dependent manner. This dose-response effect enabled the validation of a standard curve for calculation of the concentration of IL-1Ra or, inversely, the concentration of neutralizing anti-IL-1Ra antibodies in cell culture medium or sera. The assay used CCK-8 as an indicator of proliferation. The dose-response relationship between rhIL-1Ra (dose range of 5-75 ng/ml rhIL-1Ra) and A375.S2 cell proliferation was sigmoidal and fitted a four-parameter logistic model. The percent coefficients of variation (%CVs) of quality control samples were 12.5 and 11.9% for intra-assay repeatability and 14.5 and 19.5% for inter-assay repeatability, while the total accuracy was in the range of 97.2-103.6%. For the neutralization assay, the optimal sample dilution factor was found to be 40-fold and the reasonable standard for positive and negative decision was calculated to be 59.4% neutralization rate. The %CVs of quality control samples were 12.7 and 24.0% for intra-assay repeatability and 11.6 and 30.0% for inter-assay repeatability. Analysis using the assay showed that rats could produce neutralizing anti-IL-1Ra antibodies after repeated intramuscular injection with rhIL-1Ra, and this response was not significantly dependent on the dose injected. PMID:26153108

  14. Mobile Calibration Based on Laser Metrology and Approximation Networks

    PubMed Central

    Muñoz-Rodriguez, J. Apolinar

    2010-01-01

    A mobile calibration technique for three-dimensional vision is presented. In this method, vision parameters are computed automatically by approximation networks built based on the position of a camera and image processing of a laser line. The networks also perform three-dimensional visualization. In the proposed system, the setup geometry can be modified online, whereby an online re-calibration is performed based on data provided by the network and the required modifications of extrinsic and intrinsic parameters are thus determined, overcoming any calibration limitations caused by the modification procedure. The mobile calibration also avoids procedures involving references, which are used in traditional online re-calibration methods. The proposed mobile calibration thus improves the accuracy and performance of the three-dimensional vision because online data of calibrated references are not passed on to the vision system. This work represents a contribution to the field of online re-calibration, as verified by a comparison with the results based on lighting methods, which are calibrated and re-calibrated via perspective projection. Processing time is also studied. PMID:22163622

  15. Advanced Mobility Handover for Mobile IPv6 Based Wireless Networks

    PubMed Central

    Safa Sadiq, Ali; Fisal, Norsheila Binti; Ghafoor, Kayhan Zrar; Lloret, Jaime

    2014-01-01

    We propose an Advanced Mobility Handover scheme (AMH) in this paper for seamless mobility in MIPv6-based wireless networks. In the proposed scheme, the mobile node utilizes a unique home IPv6 address developed to maintain communication with other corresponding nodes without a care-of-address during the roaming process. The IPv6 address for each MN during the first round of AMH process is uniquely identified by HA using the developed MN-ID field as a global permanent, which is identifying uniquely the IPv6 address of MN. Moreover, a temporary MN-ID is generated by access point each time an MN is associated with a particular AP and temporarily saved in a developed table inside the AP. When employing the AMH scheme, the handover process in the network layer is performed prior to its default time. That is, the mobility handover process in the network layer is tackled by a trigger developed AMH message to the next access point. Thus, a mobile node keeps communicating with the current access point while the network layer handover is executed by the next access point. The mathematical analyses and simulation results show that the proposed scheme performs better as compared with the existing approaches. PMID:25614890

  16. Mekong Basin Disease Surveillance (MBDS): a trust-based network.

    PubMed

    Phommasack, Bounlay; Jiraphongsa, Chuleeporn; Ko Oo, Moe; Bond, Katherine C; Phaholyothin, Natalie; Suphanchaimat, Rapeepong; Ungchusak, Kumnuan; Macfarlane, Sarah B

    2013-01-01

    The Mekong Basin Disease Surveillance (MBDS) network was formally established in 2001 through a Memorandum of Understanding signed by six Ministers of Health of the countries in the Greater Mekong sub-region: Cambodia, China (Yunnan and Guangxi), Lao PDR, Myanmar, Thailand and Vietnam. The main areas of focus of the network are to: i) improve cross-border infectious disease outbreak investigation and response by sharing surveillance data and best practices in disease recognition and reporting, and by jointly responding to outbreaks; ii) develop expertise in epidemiological surveillance across the countries; and iii) enhance communication between the countries. Comprised of senior health officials, epidemiologists, health practitioners, and other professionals, the MBDS has grown and matured over the years into an entity based on mutual trust that can be sustained into the future. Other regions have started emulating the network's pioneering work. In this paper, we describe the development of MBDS, the way in which it operates today, and some of its achievements. We present key challenges the network has faced and lessons its members have learned about how to develop sufficient trust for health and other professionals to alert each other to disease threats across national borders and thereby more effectively combat these threats. PMID:23362411

  17. Graphics processing unit-based alignment of protein interaction networks.

    PubMed

    Xie, Jiang; Zhou, Zhonghua; Ma, Jin; Xiang, Chaojuan; Nie, Qing; Zhang, Wu

    2015-08-01

    Network alignment is an important bridge to understanding human protein-protein interactions (PPIs) and functions through model organisms. However, the underlying subgraph isomorphism problem complicates and increases the time required to align protein interaction networks (PINs). Parallel computing technology is an effective solution to the challenge of aligning large-scale networks via sequential computing. In this study, the typical Hungarian-Greedy Algorithm (HGA) is used as an example for PIN alignment. The authors propose a HGA with 2-nearest neighbours (HGA-2N) and implement its graphics processing unit (GPU) acceleration. Numerical experiments demonstrate that HGA-2N can find alignments that are close to those found by HGA while dramatically reducing computing time. The GPU implementation of HGA-2N optimises the parallel pattern, computing mode and storage mode and it improves the computing time ratio between the CPU and GPU compared with HGA when large-scale networks are considered. By using HGA-2N in GPUs, conserved PPIs can be observed, and potential PPIs can be predicted. Among the predictions based on 25 common Gene Ontology terms, 42.8% can be found in the Human Protein Reference Database. Furthermore, a new method of reconstructing phylogenetic trees is introduced, which shows the same relationships among five herpes viruses that are obtained using other methods. PMID:26243827

  18. Mekong Basin Disease Surveillance (MBDS): A Trust-Based Network

    PubMed Central

    Phommasack, Bounlay; Jiraphongsa, Chuleeporn; Ko Oo, Moe; Bond, Katherine C.; Phaholyothin, Natalie; Suphanchaimat, Rapeepong; Ungchusak, Kumnuan; Macfarlane, Sarah B.

    2013-01-01

    The Mekong Basin Disease Surveillance (MBDS) network was formally established in 2001 through a Memorandum of Understanding signed by six Ministers of Health of the countries in the Greater Mekong sub-region: Cambodia, China (Yunnan and Guangxi), Lao PDR, Myanmar, Thailand and Vietnam. The main areas of focus of the network are to: i) improve cross-border infectious disease outbreak investigation and response by sharing surveillance data and best practices in disease recognition and reporting, and by jointly responding to outbreaks; ii) develop expertise in epidemiological surveillance across the countries; and iii) enhance communication between the countries. Comprised of senior health officials, epidemiologists, health practitioners, and other professionals, the MBDS has grown and matured over the years into an entity based on mutual trust that can be sustained into the future. Other regions have started emulating the network's pioneering work. In this paper, we describe the development of MBDS, the way in which it operates today, and some of its achievements. We present key challenges the network has faced and lessons its members have learned about how to develop sufficient trust for health and other professionals to alert each other to disease threats across national borders and thereby more effectively combat these threats. PMID:23362411

  19. Clustered Numerical Data Analysis Using Markov Lie Monoid Based Networks

    NASA Astrophysics Data System (ADS)

    Johnson, Joseph

    2016-03-01

    We have designed and build an optimal numerical standardization algorithm that links numerical values with their associated units, error level, and defining metadata thus supporting automated data exchange and new levels of artificial intelligence (AI). The software manages all dimensional and error analysis and computational tracing. Tables of entities verses properties of these generalized numbers (called ``metanumbers'') support a transformation of each table into a network among the entities and another network among their properties where the network connection matrix is based upon a proximity metric between the two items. We previously proved that every network is isomorphic to the Lie algebra that generates continuous Markov transformations. We have also shown that the eigenvectors of these Markov matrices provide an agnostic clustering of the underlying patterns. We will present this methodology and show how our new work on conversion of scientific numerical data through this process can reveal underlying information clusters ordered by the eigenvalues. We will also show how the linking of clusters from different tables can be used to form a ``supernet'' of all numerical information supporting new initiatives in AI.

  20. Advanced mobility handover for mobile IPv6 based wireless networks.

    PubMed

    Safa Sadiq, Ali; Fisal, Norsheila Binti; Ghafoor, Kayhan Zrar; Lloret, Jaime

    2014-01-01

    We propose an Advanced Mobility Handover scheme (AMH) in this paper for seamless mobility in MIPv6-based wireless networks. In the proposed scheme, the mobile node utilizes a unique home IPv6 address developed to maintain communication with other corresponding nodes without a care-of-address during the roaming process. The IPv6 address for each MN during the first round of AMH process is uniquely identified by HA using the developed MN-ID field as a global permanent, which is identifying uniquely the IPv6 address of MN. Moreover, a temporary MN-ID is generated by access point each time an MN is associated with a particular AP and temporarily saved in a developed table inside the AP. When employing the AMH scheme, the handover process in the network layer is performed prior to its default time. That is, the mobility handover process in the network layer is tackled by a trigger developed AMH message to the next access point. Thus, a mobile node keeps communicating with the current access point while the network layer handover is executed by the next access point. The mathematical analyses and simulation results show that the proposed scheme performs better as compared with the existing approaches. PMID:25614890