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Sample records for amorphous track models

  1. Amorphous track models: A numerical comparison study

    DEFF Research Database (Denmark)

    Greilich, Steffen; Grzanka, L.; Bassler, N.

    2010-01-01

    We present an open-source code library for amorphous track modelling which is suppose to faciliate the application and numerical comparability as well as serve as a frame-work for the implementation of new models. We show an example of using the library indicating the choice of submodels has a si...

  2. Modeling Radiation Effects of Ultrasoft X Rays on the Basis of Amorphous Track Structure.

    Science.gov (United States)

    Buch, Tamara; Scifoni, Emanuele; Krämer, Michael; Durante, Marco; Scholz, Michael; Friedrich, Thomas

    2018-01-01

    There is experimental evidence that ultrasoft X rays (0.1-5 keV) show a higher biological effectiveness than high-energy photons. Similar to high-LET radiation, this is attributed to a rather localized dose distribution associated with a considerably smaller range of secondary electrons, which results in an increasing yield of double-strand breaks (DSBs) and potentially more complex lesions. We previously reported on the application of the Giant LOop Binary LEsion (GLOBLE) model to ultrasoft X rays, in which experimental values of the relative biological effectiveness (RBE) for DSB induction were used to show that this increasing DSB yield was sufficient to explain the enhanced effectiveness in the cell inactivation potential of ultrasoft X rays. Complementary to GLOBLE, we report here on a modeling approach to predict the increased DSB yield of ultrasoft X rays on the basis of amorphous track structure formed by secondary electrons, which was derived from Monte Carlo track structure simulations. This procedure is associated with increased production of single-strand break (SSB) clusters, which are caused by the highly localized energy deposition pattern induced by low-energy photons. From this, the RBE of ultrasoft X rays can be determined and compared to experimental data, showing that the inhomogeneity of the energy deposition pattern represents the key variable to describe the increased biological effectiveness of ultrasoft X rays. Thus, this work demonstrates an extended applicability of the amorphous track structure concept and tests its limits with respect to its predictive power. The employed model mechanism offers a possible explanation for how the cellular response to ultrasoft X rays is directly linked to the energy deposition properties on the nanometric scale.

  3. Cell survival in carbon beams - comparison of amorphous track model predictions

    DEFF Research Database (Denmark)

    Grzanka, L.; Greilich, S.; Korcyl, M.

    distribution models, and gamma response models was developed. This software can be used for direct numerical comparison between the models, submodels and their parameters and experimental data. In the present paper, we look at 10%-survival data from cell lines irradiated in vitro with carbon and proton beams...... neutrons, stopped pions, and heavy ion beams. Nucl Instrum Meth. 1973;111:93-116. 2.Weyrather WK, Kraft G. RBE of carbon ions: experimental data and the strategy of RBE calculation for treatment planning. Radiother Oncol. 2004;73(Suppl 2):161-9. 3.Greilich S, Grzanka L, Bassler N, Andersen CE, Jäkel O...... irradiation. The aim of this paper is to compare the predictions from different amorphous approaches found in the literature - more specifically the phenomenological, analytical model by Katz and co-workers [1] and a Monte-Carlo based full as implemented for example in the local effect model by Scholz et al...

  4. Amorphous track predictions in ‘libamtrack’ for alanine relative effectiveness in ion beams

    DEFF Research Database (Denmark)

    Herrmann, Rochus; Greilich, Steffen; Grzanka, Leszek

    2011-01-01

    Solid state dosimetery in therapeutic ion beams is seriously hampered by ionisation density effects. In most cases the use of empirical corrections is limited and therefore model predictions, especially from amorphous track models (ATMs), play a major role. Due to its high saturation dose...

  5. Model for amorphous aggregation processes

    Science.gov (United States)

    Stranks, Samuel D.; Ecroyd, Heath; van Sluyter, Steven; Waters, Elizabeth J.; Carver, John A.; von Smekal, Lorenz

    2009-11-01

    The amorphous aggregation of proteins is associated with many phenomena, ranging from the formation of protein wine haze to the development of cataract in the eye lens and the precipitation of recombinant proteins during their expression and purification. While much literature exists describing models for linear protein aggregation, such as amyloid fibril formation, there are few reports of models which address amorphous aggregation. Here, we propose a model to describe the amorphous aggregation of proteins which is also more widely applicable to other situations where a similar process occurs, such as in the formation of colloids and nanoclusters. As first applications of the model, we have tested it against experimental turbidimetry data of three proteins relevant to the wine industry and biochemistry, namely, thaumatin, a thaumatinlike protein, and α -lactalbumin. The model is very robust and describes amorphous experimental data to a high degree of accuracy. Details about the aggregation process, such as shape parameters of the aggregates and rate constants, can also be extracted.

  6. Biophysical calculations of cell killing probability by the amorphous track structure model for heavy-ion beams

    International Nuclear Information System (INIS)

    Kase, Yuki; Matsufuji, Naruhiro; Furusawa, Yoshiya; Kanai, Tatsuaki

    2007-01-01

    In a treatment planning of heavy-ion radiotherapy, it is necessary to estimate the biological effect of the heavy-ion beams. Physical dose should be associated with the relative biological effectiveness (RBE) at each point. Presently, carbon ion radiotherapy has been carried out at the National Institute Radiological Sciences (NIRS) in Japan and the Gesellschaft fuer Schwerionenforschung mbH (GSI) in Germany. Both facilities take individual approach for the calculation of the RBE value. At NIRS, the classical LQ model has been used while the local effect model (LEM) has been incorporated into the treatment planning system at GSI. The first aim of this study is to explain the RBE model of NIRS by the microdosimetric kinetic model (MKM). In addition, the clarification of similarities and differences between the MKM and the LEM was also investigated. (author)

  7. Atomistic Models of Amorphous Semiconductors

    NARCIS (Netherlands)

    Jarolimek, K.

    2011-01-01

    Crystalline silicon is probably the best studied material, widely used by the semiconductor industry. The subject of this thesis is an intriguing form of this element namely amorphous silicon. It can contain a varying amount of hydrogen and is denoted as a-Si:H. It completely lacks the neat long

  8. Fluctuation microscopy analysis of amorphous silicon models

    International Nuclear Information System (INIS)

    Gibson, J.M.; Treacy, M.M.J.

    2017-01-01

    Highlights: • Studied competing computer models for amorphous silicon and simulated fluctuation microscopy data. • Show that only paracrystalline/random network composite can fit published data. • Specifically show that pure random network or random network with void models do not fit available data. • Identify a new means to measure volume fraction of ordered material. • Identify unreported limitations of the Debye model for simulating fluctuation microscopy data. - Abstract: Using computer-generated models we discuss the use of fluctuation electron microscopy (FEM) to identify the structure of amorphous silicon. We show that a combination of variable resolution FEM to measure the correlation length, with correlograph analysis to obtain the structural motif, can pin down structural correlations. We introduce the method of correlograph variance as a promising means of independently measuring the volume fraction of a paracrystalline composite. From comparisons with published data, we affirm that only a composite material of paracrystalline and continuous random network that is substantially paracrystalline could explain the existing experimental data, and point the way to more precise measurements on amorphous semiconductors. The results are of general interest for other classes of disordered materials.

  9. Atomistic modeling of ion beam induced amorphization in silicon

    International Nuclear Information System (INIS)

    Pelaz, Lourdes; Marques, Luis A.; Lopez, Pedro; Santos, Ivan; Aboy, Maria; Barbolla, Juan

    2005-01-01

    Ion beam induced amorphization in Si has attracted significant interest since the beginning of the use of ion implantation for the fabrication of Si devices. Nowadays, a renewed interest in the modeling of amorphization mechanisms at atomic level has arisen due to the use of preamorphizing implants and high dopant implantation doses for the fabrication of nanometric-scale Si devices. In this work, we briefly describe the existing phenomenological and defect-based amorphization models. We focus on the atomistic model we have developed to describe ion beam induced amorphization in Si. In our model, the building block for the amorphous phase is the bond defect or IV pair, whose stability increases with the number of surrounding IV pairs. This feature explains the regrowth behavior of different damage topologies and the kinetics of the crystalline to amorphous transition. The model provides excellent quantitative agreement with experimental results

  10. Molecular modeling of amorphous and crosslinked cellulose

    Science.gov (United States)

    Chen, Wei

    2001-07-01

    Structure-property relationships in cellulose crosslinked with both conventional and elastomeric crosslinking agents were successfully calculated using molecular modeling. The observed yielding for these amorphous cellulose models, which occurred at approximately 8% strain according to the calculated stress-strain relationship, is due to the disruption of hydrogen bonds, the secondary crosslinks, between cellulose chain segments. Crosslinks hold cellulose chain segments together and block chain slippage to give cellulose fibers a higher initial modulus and better elastic response. However, these crosslinks restrict chain movement so that stress is concentrated in regions of the structure and cavities are formed and developed in these regions of the models, which correlate to final fiber failure. The flexibility and response to applied external force for some potential crosslink structures were examined by molecular modeling. These molecules, which have small energy differences between conformational states, are highly coiled and have small mean end-to-end distances (accounting for 40% to 50% of the length of their fully extended chains). The presence of oxygen atoms in the backbone along with asymmetric non-polar side groups, such as methyl groups, can greatly reduce the energy difference and the energy barrier between conformational states and can thus make chains highly coiled and easy to be extended. Decane crosslinks introduced more freedom to cellulose chain segments but didn't improve the deformation recovery in cellulose models. Conformational transitions were observed in decane crosslinks during deformation. Cellulose models crosslinked with poly(propylene oxide) pentamers or with the N-methyl substituted peptide pentamers show good deformation recovery without affecting the breaking strain. Both crosslinks didn't significantly change the initial modulus and the yielding behavior of cellulose. No conformation transitions were observed in these crosslinks

  11. Comprehensive modeling of ion-implant amorphization in silicon

    International Nuclear Information System (INIS)

    Mok, K.R.C.; Jaraiz, M.; Martin-Bragado, I.; Rubio, J.E.; Castrillo, P.; Pinacho, R.; Srinivasan, M.P.; Benistant, F.

    2005-01-01

    A physically based model has been developed to simulate the ion-implant induced damage accumulation up to amorphization in silicon. Based on damage structures known as amorphous pockets (AP), which are three-dimensional, irregularly shaped agglomerates of interstitials (I) and vacancies (V) surrounded by crystalline silicon, the model is able to reproduce a wide range of experimental observations of damage accumulation and amorphization with interdependent implantation parameters. Instead of recrystallizing the I's and V's instantaneously, the recrystallization rate of an AP containing nI and mV is a function of its effective size, defined as min(n, m), irrespective of its internal spatial configuration. The parameters used in the model were calibrated using the experimental silicon amorphous-crystalline transition temperature as a function of dose rate for C, Si, and Ge. The model is able to show the superlinear damage build-up with dose, the extent of amorphous layer and the superadditivity effect of polyatomic ions

  12. Molecular modeling of amorphous, non-woven polymer networks.

    Science.gov (United States)

    Krausse, Constantin A; Milek, Theodor; Zahn, Dirk

    2015-10-01

    We outline a simple and efficient approach to generating molecular models of amorphous polymer networks. Similar to established techniques of preparing woven polymer networks from quenching high-temperature molecular simulation runs, we use a molecular dynamics simulations of a generic melt as starting points. This generic melt is however only used to describe parts of the polymers, namely the cross-linker units which positions are adopted from particle positions of the quenched melt. Specific degrees of network connectivity are tuned by geometric criteria for linker-linker connections and by suitable multi-body interaction potentials applied to the generic melt simulations. Using this technique we demonstrate adjusting fourfold linker coordination in amorphous polymer networks comprising 10-20% under-coordinated linkers. Graphical Abstract Molecular modeling of amorphous, non-woven polymer networks.

  13. Self-consistent modeling of amorphous silicon devices

    International Nuclear Information System (INIS)

    Hack, M.

    1987-01-01

    The authors developed a computer model to describe the steady-state behaviour of a range of amorphous silicon devices. It is based on the complete set of transport equations and takes into account the important role played by the continuous distribution of localized states in the mobility gap of amorphous silicon. Using one set of parameters they have been able to self-consistently simulate the current-voltage characteristics of p-i-n (or n-i-p) solar cells under illumination, the dark behaviour of field-effect transistors, p-i-n diodes and n-i-n diodes in both the ohmic and space charge limited regimes. This model also describes the steady-state photoconductivity of amorphous silicon, in particular, its dependence on temperature, doping and illumination intensity

  14. A model for stored energy in amorphous silica

    International Nuclear Information System (INIS)

    Tinivella, G.

    1980-12-01

    The observed saturation value of stored energy in irradiated amorphous silica is too big to be explained by the energy of recombined non-grouped defects. The hypothesis that it can be due to a structural change has been tested, and a simple model based on the fluctuation of the atomic distances shows a reasonable agreement with the experimental data. (author)

  15. TRACKING CLIMATE MODELS

    Data.gov (United States)

    National Aeronautics and Space Administration — CLAIRE MONTELEONI*, GAVIN SCHMIDT, AND SHAILESH SAROHA* Climate models are complex mathematical models designed by meteorologists, geophysicists, and climate...

  16. Design, Construction and Effectiveness Analysis of Hybrid Automatic Solar Tracking System for Amorphous and Crystalline Solar Cells

    OpenAIRE

    Bhupendra Gupta

    2013-01-01

    - This paper concerns the design and construction of a Hybrid solar tracking system. The constructed device was implemented by integrating it with Amorphous & Crystalline Solar Panel, three dimensional freedom mechanism and microcontroller. The amount of power available from a photovoltaic panel is determined by three parameters, the type of solar tracker, materials of solar panel and the intensity of the sunlight. The objective of this paper is to present analysis on the use of two differ...

  17. Track structure in biological models.

    Science.gov (United States)

    Curtis, S B

    1986-01-01

    High-energy heavy ions in the galactic cosmic radiation (HZE particles) may pose a special risk during long term manned space flights outside the sheltering confines of the earth's geomagnetic field. These particles are highly ionizing, and they and their nuclear secondaries can penetrate many centimeters of body tissue. The three dimensional patterns of ionizations they create as they lose energy are referred to as their track structure. Several models of biological action on mammalian cells attempt to treat track structure or related quantities in their formulation. The methods by which they do this are reviewed. The proximity function is introduced in connection with the theory of Dual Radiation Action (DRA). The ion-gamma kill (IGK) model introduces the radial energy-density distribution, which is a smooth function characterizing both the magnitude and extension of a charged particle track. The lethal, potentially lethal (LPL) model introduces lambda, the mean distance between relevant ion clusters or biochemical species along the track. Since very localized energy depositions (within approximately 10 nm) are emphasized, the proximity function as defined in the DRA model is not of utility in characterizing track structure in the LPL formulation.

  18. Graph Model Based Indoor Tracking

    DEFF Research Database (Denmark)

    Jensen, Christian Søndergaard; Lu, Hua; Yang, Bin

    2009-01-01

    The tracking of the locations of moving objects in large indoor spaces is important, as it enables a range of applications related to, e.g., security and indoor navigation and guidance. This paper presents a graph model based approach to indoor tracking that offers a uniform data management...... infrastructure for different symbolic positioning technologies, e.g., Bluetooth and RFID. More specifically, the paper proposes a model of indoor space that comprises a base graph and mappings that represent the topology of indoor space at different levels. The resulting model can be used for one or several...... indoor positioning technologies. Focusing on RFID-based positioning, an RFID specific reader deployment graph model is built from the base graph model. This model is then used in several algorithms for constructing and refining trajectories from raw RFID readings. Empirical studies with implementations...

  19. Modeling Ballasted Tracks for Runoff Coefficient C

    Science.gov (United States)

    2012-08-01

    In this study, the Regional Transportation District (RTD)s light rail tracks were modeled to determine the Rational Method : runoff coefficient, C, values corresponding to ballasted tracks. To accomplish this, a laboratory study utilizing a : rain...

  20. Dynamic comparison of different types of slab tracks and ballasted track using a flexible track model

    OpenAIRE

    Blanco-Lorenzo, Julio; Santamaría Manrique, Javier; García Vadillo, Ernesto; Oyarzabal de Celis, Olatz

    2011-01-01

    The dynamic performance of a ballasted track and three types of slab tracks is analysed and compared by means of a comprehensive dynamic model of the train-track system, generated using two commercial analysis software packages: the commercial Multibody System (MBS) analysis software SIMPACK and the Finite Element Method (FEM) analysis software NASTRAN. The use of a commercial MBS software makes it possible to include in a reliable way models of advanced non-linear wheel-rail contact, as well...

  1. Tracks FAQs: What is Modeled Air Data?

    Centers for Disease Control (CDC) Podcasts

    2011-04-25

    In this podcast, CDC Tracking experts discuss modeled air data. Do you have a question for our Tracking experts? Please e-mail questions to trackingsupport@cdc.gov.  Created: 4/25/2011 by National Center for Environmental Health, Division of Environmental Hazards and Health Effects, Environmental Health Tracking Branch.   Date Released: 4/25/2011.

  2. Modelling structure and properties of amorphous silicon boron nitride ceramics

    Directory of Open Access Journals (Sweden)

    Johann Christian Schön

    2011-06-01

    Full Text Available Silicon boron nitride is the parent compound of a new class of high-temperature stable amorphous ceramics constituted of silicon, boron, nitrogen, and carbon, featuring a set of properties that is without precedent, and represents a prototypical random network based on chemical bonds of predominantly covalent character. In contrast to many other amorphous materials of technological interest, a-Si3B3N7 is not produced via glass formation, i.e. by quenching from a melt, the reason being that the binary components, BN and Si3N4, melt incongruently under standard conditions. Neither has it been possible to employ sintering of μm-size powders consisting of binary nitrides BN and Si3N4. Instead, one employs the so-called sol-gel route starting from single component precursors such as TADB ((SiCl3NH(BCl2. In order to determine the atomic structure of this material, it has proven necessary to simulate the actual synthesis route.Many of the exciting properties of these ceramics are closely connected to the details of their amorphous structure. To clarify this structure, it is necessary to employ not only experimental probes on many length scales (X-ray, neutron- and electron scattering; complex NMR experiments; IR- and Raman scattering, but also theoretical approaches. These address the actual synthesis route to a-Si3B3N7, the structural properties, the elastic and vibrational properties, aging and coarsening behaviour, thermal conductivity and the metastable phase diagram both for a-Si3B3N7 and possible silicon boron nitride phases with compositions different from Si3N4: BN = 1 : 3. Here, we present a short comprehensive overview over the insights gained using molecular dynamics and Monte Carlo simulations to explore the energy landscape of a-Si3B3N7, model the actual synthesis route and compute static and transport properties of a-Si3BN7.

  3. A Predictive Maintenance Model for Railway Tracks

    DEFF Research Database (Denmark)

    Li, Rui; Wen, Min; Salling, Kim Bang

    2015-01-01

    presents a mathematical model based on Mixed Integer Programming (MIP) which is designed to optimize the predictive railway tamping activities for ballasted track for the time horizon up to four years. The objective function is setup to minimize the actual costs for the tamping machine (measured by time......). Five technical and economic aspects are taken into account to schedule tamping: (1) track degradation of the standard deviation of the longitudinal level over time; (2) track geometrical alignment; (3) track quality thresholds based on the train speed limits; (4) the dependency of the track quality...... recovery on the track quality after tamping operation and (5) Tamping machine operation factors. A Danish railway track between Odense and Fredericia with 57.2 km of length is applied for a time period of two to four years in the proposed maintenance model. The total cost can be reduced with up to 50...

  4. Modeling SiC swelling under irradiation: Influence of amorphization

    CERN Document Server

    Romano, A; Defranceschi, M; Yip, S

    2003-01-01

    Irradiation-induced swelling of SiC is investigated using a molecular dynamics simulation-based methodology. To mimic the effect of heavy ion irradiation extended amorphous areas of various sizes are introduced in a crystalline SiC sample, and the resulting configurations are relaxed using molecular dynamics at constant pressure. Simulation results compare very well with data from existing ion implantation experiments. Analysis of the relaxed configurations shows very clearly that SiC swelling does not scale linearly with the amorphous fraction introduced. Two swelling regimes are observed depending on the size of the initial amorphous area: for small amorphous zones swelling scales like the amorphous fraction to the power 2/3, while for larger areas it scales like the amorphous fraction to the powers 2/3 and 4/3. Similar dependences on the amorphous fraction are obtained for the number of homonuclear bonds present in the initial amorphous volume and for the number of short bonds created at the interface betw...

  5. The forward tracking, an optical model method

    CERN Document Server

    Benayoun, M

    2002-01-01

    This Note describes the so-called Forward Tracking, and the underlying optical model, developed in the context of LHCb-Light studies. Starting from Velo tracks, cheated or found by real pattern recognition, the tracks are found in the ST1-3 chambers after the magnet. The main ingredient to the method is a parameterisation of the track in the ST1-3 region, based on the Velo track parameters and an X seed in one ST station. Performance with the LHCb-Minus and LHCb-Light setups is given.

  6. Atomistic modeling of defect evolution in Si for amorphizing and subamorphizing implants

    International Nuclear Information System (INIS)

    Lopez, Pedro; Pelaz, Lourdes; Marques, Luis A.; Santos, Ivan; Aboy, Maria; Barbolla, Juan

    2004-01-01

    Solid phase epitaxial regrowth of pre-amorphizing implants has received significant attention as a method to achieve high dopant activation with minimal diffusion at low implant temperatures and suppress channelling. Therefore, a good understanding of the amorphization and regrowth mechanisms is required in process simulators. We present an atomistic amorphization and recrystallization model that uses the interstitial-vacancy (I-V) pair as a building block to describe the amorphous phase. I-V pairs are locally characterized by the number of neighbouring I-V pairs. This feature captures the damage generation and the dynamical annealing during ion implantation, and also explains the annealing behaviour of amorphous layers and amorphous pockets

  7. Building the RHIC tracking lattice model

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Y.; Fischer, W.; Tepikian, S.

    2010-01-27

    In this note we outline the procedure to build a realistic lattice model for the RHIC beam-beam tracking simulation. We will install multipole field errors in the arc main dipoles, arc main quadrupols and interaction region magnets (DX, D0, and triplets) and introduce a residual closed orbit, tune ripples, and physical apertures in the tracking lattice model. Nonlinearities such as local IR multipoles, second order chromaticies and third order resonance driving terms are also corrected before tracking.

  8. Experimental and Computer Modelling Studies of Metastability of Amorphous Silicon Based Solar Cells

    NARCIS (Netherlands)

    Munyeme, Geoffrey

    2003-01-01

    We present a combination of experimental and computer modelling studies of the light induced degradation in the performance of amorphous silicon based single junction solar cells. Of particular interest in this study is the degradation kinetics of different types of amorphous silicon single junction

  9. Thermodynamical modeling of nuclear glasses: coexistence of amorphous phases

    International Nuclear Information System (INIS)

    Adjanor, G.

    2007-11-01

    Investigating the stability of borosilicate glasses used in the nuclear industry with respect to phase separation requires to estimate the Gibbs free energies of the various phases appearing in the material. In simulation, using current computational resources, a direct state-sampling of a glassy system with respect to its ensemble statistics is not ergodic and the estimated ensemble averages are not reliable. Our approach consists in generating, at a given cooling rate, a series of quenches, or paths connecting states of the liquid to states of the glass, and then in taking into account the probability to generate the paths leading to the different glassy states in ensembles averages. In this way, we introduce a path ensemble formalism and calculate a Landau free energy associated to a glassy meta-basin. This method was validated by accurately mapping the free energy landscape of a 38-atom glassy cluster. We then applied this approach to the calculation of the Gibbs free energies of binary amorphous Lennard-Jones alloys, and checked the correlation between the observed tendencies to order or to phase separate and the computed Gibbs free energies. We finally computed the driving force to phase separation in a simplified three-oxide nuclear glass modeled by a Born-Mayer-Huggins potential that includes a three-body term, and we compared the estimated quantities to the available experimental data. (author)

  10. Local yield stress statistics in model amorphous solids

    Science.gov (United States)

    Barbot, Armand; Lerbinger, Matthias; Hernandez-Garcia, Anier; García-García, Reinaldo; Falk, Michael L.; Vandembroucq, Damien; Patinet, Sylvain

    2018-03-01

    We develop and extend a method presented by Patinet, Vandembroucq, and Falk [Phys. Rev. Lett. 117, 045501 (2016), 10.1103/PhysRevLett.117.045501] to compute the local yield stresses at the atomic scale in model two-dimensional Lennard-Jones glasses produced via differing quench protocols. This technique allows us to sample the plastic rearrangements in a nonperturbative manner for different loading directions on a well-controlled length scale. Plastic activity upon shearing correlates strongly with the locations of low yield stresses in the quenched states. This correlation is higher in more structurally relaxed systems. The distribution of local yield stresses is also shown to strongly depend on the quench protocol: the more relaxed the glass, the higher the local plastic thresholds. Analysis of the magnitude of local plastic relaxations reveals that stress drops follow exponential distributions, justifying the hypothesis of an average characteristic amplitude often conjectured in mesoscopic or continuum models. The amplitude of the local plastic rearrangements increases on average with the yield stress, regardless of the system preparation. The local yield stress varies with the shear orientation tested and strongly correlates with the plastic rearrangement locations when the system is sheared correspondingly. It is thus argued that plastic rearrangements are the consequence of shear transformation zones encoded in the glass structure that possess weak slip planes along different orientations. Finally, we justify the length scale employed in this work and extract the yield threshold statistics as a function of the size of the probing zones. This method makes it possible to derive physically grounded models of plasticity for amorphous materials by directly revealing the relevant details of the shear transformation zones that mediate this process.

  11. Fracture of Carbon Nanotube - Amorphous Carbon Composites: Molecular Modeling

    Science.gov (United States)

    Jensen, Benjamin D.; Wise, Kristopher E.; Odegard, Gregory M.

    2015-01-01

    Carbon nanotubes (CNTs) are promising candidates for use as reinforcements in next generation structural composite materials because of their extremely high specific stiffness and strength. They cannot, however, be viewed as simple replacements for carbon fibers because there are key differences between these materials in areas such as handling, processing, and matrix design. It is impossible to know for certain that CNT composites will represent a significant advance over carbon fiber composites before these various factors have been optimized, which is an extremely costly and time intensive process. This work attempts to place an upper bound on CNT composite mechanical properties by performing molecular dynamics simulations on idealized model systems with a reactive forcefield that permits modeling of both elastic deformations and fracture. Amorphous carbon (AC) was chosen for the matrix material in this work because of its structural simplicity and physical compatibility with the CNT fillers. It is also much stiffer and stronger than typical engineering polymer matrices. Three different arrangements of CNTs in the simulation cell have been investigated: a single-wall nanotube (SWNT) array, a multi-wall nanotube (MWNT) array, and a SWNT bundle system. The SWNT and MWNT array systems are clearly idealizations, but the SWNT bundle system is a step closer to real systems in which individual tubes aggregate into large assemblies. The effect of chemical crosslinking on composite properties is modeled by adding bonds between the CNTs and AC. The balance between weakening the CNTs and improving fiber-matrix load transfer is explored by systematically varying the extent of crosslinking. It is, of course, impossible to capture the full range of deformation and fracture processes that occur in real materials with even the largest atomistic molecular dynamics simulations. With this limitation in mind, the simulation results reported here provide a plausible upper limit on

  12. Deformable Models for Eye Tracking

    DEFF Research Database (Denmark)

    Vester-Christensen, Martin; Leimberg, Denis; Ersbøll, Bjarne Kjær

    2005-01-01

    A deformable template method for eye tracking on full face images is presented. The strengths of the method are that it is fast and retains accuracy independently of the resolution. We compare the me\\$\\backslash\\$-thod with a state of the art active contour approach, showing that the heuristic...

  13. Model-Based Motion Tracking of Infants

    DEFF Research Database (Denmark)

    Olsen, Mikkel Damgaard; Herskind, Anna; Nielsen, Jens Bo

    2014-01-01

    Even though motion tracking is a widely used technique to analyze and measure human movements, only a few studies focus on motion tracking of infants. In recent years, a number of studies have emerged focusing on analyzing the motion pattern of infants, using computer vision. Most of these studie...... that resembles the body surface of an infant, where the model is based on simple geometric shapes and a hierarchical skeleton model....

  14. Modeling of amorphous carbon structures with arbitrary structural constraints.

    Science.gov (United States)

    Jornada, F H; Gava, V; Martinotto, A L; Cassol, L A; Perottoni, C A

    2010-10-06

    In this paper we describe a method to generate amorphous structures with arbitrary structural constraints. This method employs the simulated annealing algorithm to minimize a simple yet carefully tailored cost function (CF). The cost function is composed of two parts: a simple harmonic approximation for the energy-related terms and a cost that penalizes configurations that do not have atoms in the desired coordinations. Using this approach, we generated a set of amorphous carbon structures spawning nearly all the possible combinations of sp, sp(2) and sp(3) hybridizations. The bulk moduli of this set of amorphous carbons structures was calculated using Brenner's potential. The bulk modulus strongly depends on the mean coordination, following a power-law behavior with an exponent ν = 1.51 ± 0.17. A modified cost function that segregates carbon with different hybridizations is also presented, and another set of structures was generated. With this new set of amorphous materials, the correlation between the bulk modulus and the mean coordination weakens. The method proposed can be easily modified to explore the effects on the physical properties of the presence of hydrogen, dangling bonds, and structural features such as carbon rings.

  15. AMORPHOUS SILICON ELECTRONIC STRUCTURE MODELING AND BASIC ELECTRO-PHYSICAL PARAMETERS CALCULATION

    Directory of Open Access Journals (Sweden)

    B. A. Golodenko

    2014-01-01

    Full Text Available Summary. The amorphous semiconductor has any unique processing characteristics and it is perspective material for electronic engineering. However, we have not authentic information about they atomic structure and it is essential knot for execution calculation they electronic states and electro physical properties. The author's methods give to us decision such problem. This method allowed to calculation the amorphous silicon modeling cluster atomics Cartesian coordinates, determined spectrum and density its electronic states and calculation the basics electro physical properties of the modeling cluster. At that determined numerical means of the energy gap, energy Fermi, electron concentration inside valence and conduction band for modeling cluster. The find results provides real ability for purposeful control to type and amorphous semiconductor charge carriers concentration and else provides relation between atomic construction and other amorphous substance physical properties, for example, heat capacity, magnetic susceptibility and other thermodynamic sizes.

  16. Optimal Appearance Model for Visual Tracking.

    Directory of Open Access Journals (Sweden)

    Yuru Wang

    Full Text Available Many studies argue that integrating multiple cues in an adaptive way increases tracking performance. However, what is the definition of adaptiveness and how to realize it remains an open issue. On the premise that the model with optimal discriminative ability is also optimal for tracking the target, this work realizes adaptiveness and robustness through the optimization of multi-cue integration models. Specifically, based on prior knowledge and current observation, a set of discrete samples are generated to approximate the foreground and background distribution. With the goal of optimizing the classification margin, an objective function is defined, and the appearance model is optimized by introducing optimization algorithms. The proposed optimized appearance model framework is embedded into a particle filter for a field test, and it is demonstrated to be robust against various kinds of complex tracking conditions. This model is general and can be easily extended to other parameterized multi-cue models.

  17. How to incorporate generic refraction models into multistatic tracking algorithms

    Science.gov (United States)

    Crouse, D. F.

    The vast majority of literature published on target tracking ignores the effects of atmospheric refraction. When refraction is considered, the solutions are generally tailored to a simple exponential atmospheric refraction model. This paper discusses how arbitrary refraction models can be incorporated into tracking algorithms. Attention is paid to multistatic tracking problems, where uncorrected refractive effects can worsen track accuracy and consistency in centralized tracking algorithms, and can lead to difficulties in track-to-track association in distributed tracking filters. Monostatic and bistatic track initialization using refraction-corrupted measurements is discussed. The results are demonstrated using an exponential refractive model, though an arbitrary refraction profile can be substituted.

  18. Melody Track Selection Using Discriminative Language Model

    Science.gov (United States)

    Wu, Xiao; Li, Ming; Suo, Hongbin; Yan, Yonghong

    In this letter we focus on the task of selecting the melody track from a polyphonic MIDI file. Based on the intuition that music and language are similar in many aspects, we solve the selection problem by introducing an n-gram language model to learn the melody co-occurrence patterns in a statistical manner and determine the melodic degree of a given MIDI track. Furthermore, we propose the idea of using background model and posterior probability criteria to make modeling more discriminative. In the evaluation, the achieved 81.6% correct rate indicates the feasibility of our approach.

  19. Replication of surface features from a master model to an amorphous metallic article

    Science.gov (United States)

    Johnson, William L.; Bakke, Eric; Peker, Atakan

    1999-01-01

    The surface features of an article are replicated by preparing a master model having a preselected surface feature thereon which is to be replicated, and replicating the preselected surface feature of the master model. The replication is accomplished by providing a piece of a bulk-solidifying amorphous metallic alloy, contacting the piece of the bulk-solidifying amorphous metallic alloy to the surface of the master model at an elevated replication temperature to transfer a negative copy of the preselected surface feature of the master model to the piece, and separating the piece having the negative copy of the preselected surface feature from the master model.

  20. Enhanced index tracking modelling in portfolio optimization

    Science.gov (United States)

    Lam, W. S.; Hj. Jaaman, Saiful Hafizah; Ismail, Hamizun bin

    2013-09-01

    Enhanced index tracking is a popular form of passive fund management in stock market. It is a dual-objective optimization problem, a trade-off between maximizing the mean return and minimizing the risk. Enhanced index tracking aims to generate excess return over the return achieved by the index without purchasing all of the stocks that make up the index by establishing an optimal portfolio. The objective of this study is to determine the optimal portfolio composition and performance by using weighted model in enhanced index tracking. Weighted model focuses on the trade-off between the excess return and the risk. The results of this study show that the optimal portfolio for the weighted model is able to outperform the Malaysia market index which is Kuala Lumpur Composite Index because of higher mean return and lower risk without purchasing all the stocks in the market index.

  1. Object tracking using active appearance models

    DEFF Research Database (Denmark)

    Stegmann, Mikkel Bille

    2001-01-01

    This paper demonstrates that (near) real-time object tracking can be accomplished by the deformable template model; the Active Appearance Model (AAM) using only low-cost consumer electronics such as a PC and a web-camera. Successful object tracking of perspective, rotational and translational...... transformations was carried out using a training set of five images. The tracker was automatically initialised by a described multi-scale initialisation method and achieved a performance in the range of 7-10 frames per second....

  2. The effect of empirical potential functions on modeling of amorphous carbon using molecular dynamics method

    International Nuclear Information System (INIS)

    Li, Longqiu; Xu, Ming; Song, Wenping; Ovcharenko, Andrey; Zhang, Guangyu; Jia, Ding

    2013-01-01

    Empirical potentials have a strong effect on the hybridization and structure of amorphous carbon and are of great importance in molecular dynamics (MD) simulations. In this work, amorphous carbon at densities ranging from 2.0 to 3.2 g/cm 3 was modeled by a liquid quenching method using Tersoff, 2nd REBO, and ReaxFF empirical potentials. The hybridization, structure and radial distribution function G(r) of carbon atoms were analyzed as a function of the three potentials mentioned above. The ReaxFF potential is capable to model the change of the structure of amorphous carbon and MD results are in a good agreement with experimental results and density function theory (DFT) at low density of 2.6 g/cm 3 and below. The 2nd REBO potential can be used when amorphous carbon has a very low density of 2.4 g/cm 3 and below. Considering the computational efficiency, the Tersoff potential is recommended to model amorphous carbon at a high density of 2.6 g/cm 3 and above. In addition, the influence of the quenching time on the hybridization content obtained with the three potentials is discussed.

  3. Advanced Stochastic Modeling of Railway Track Irregularities

    Directory of Open Access Journals (Sweden)

    Mengyi Zhu

    2013-01-01

    Full Text Available As an important interference source of railway vibration, track irregularity is studied in this paper. It is presented that irregularities in the vertical profile and alignment can be modeled as a Gaussian random process. The power spectral density (PSD of the irregularity is calculated and discussed. By analyzing the model, level-crossing properties as well as peak statistics are studied and compared with the observed data.

  4. Finite size effects in a model for platicity of amorphous composites

    DEFF Research Database (Denmark)

    Tyukodi, Botond; Lemarchand, Claire A.; Hansen, Jesper Schmidt

    2016-01-01

    We discuss the plastic behavior of an amorphous matrix reinforced by hard particles. A mesoscopic depinning-like model accounting for Eshelby elastic interactions is implemented. Only the effect of a plastic disorder is considered. Numerical results show a complex size dependence of the effective...... numerically. Predictions of the effective flow stress accounting for further logarithmic corrections show a very good agreement with numerical results.......We discuss the plastic behavior of an amorphous matrix reinforced by hard particles. A mesoscopic depinning-like model accounting for Eshelby elastic interactions is implemented. Only the effect of a plastic disorder is considered. Numerical results show a complex size dependence of the effective...... flow stress of the amorphous composite. In particular, the departure from the mixing law shows opposite trends associated to the competing effects of the matrix and the reinforcing particles, respectively. The reinforcing mechanisms and their effects on localization are discussed. Plastic strain...

  5. Supersolubilization and amorphization of a model basic drug, haloperidol, by interaction with weak acids.

    Science.gov (United States)

    Singh, Saumya; Parikh, Tapan; Sandhu, Harpreet K; Shah, Navnit H; Malick, A Waseem; Singhal, Dharmendra; Serajuddin, Abu T M

    2013-06-01

    To present a novel approach of greatly enhancing aqueous solubility of a model weakly basic drug, haloperidol, by using weak acids that would not form salts with the drug and to attain physically stable form of amorphous drug by drying such aqueous solutions. Aqueous solubility of haloperidol in presence of increasing concentrations of four different weak organic acids (malic, tartaric, citric, fumaric) were determined. Several concentrated aqueous solutions with differing drug-to-acid molar ratios were dried in vacuum oven, and dried materials were characterized by DSC, powder XRD, dissolution testing, and stability study. Acids were selected such that they would not form salts with haloperidol. Haloperidol solubility increased greatly with increased concentrations of malic, tartaric and citric acids, reaching >300 mg/g of solution. In contrast to the haloperidol HCl aqueous solubility of 4 mg/g, this may be called supersolubilization. Fumaric acid did not cause such solubilization as it had low water solubility. Dried solids formed dispersions of amorphous haloperidol in acids that were either amorphous or partially crystalline. Amorphous haloperidol was physically stable and had better dissolution rate than HCl salt. A novel method of drug solubilization in aqueous media by acid-base interaction is presented. Physically stable amorphous systems of drugs may also be prepared by using this organic solvent-free approach.

  6. Thermodynamical modeling of nuclear glasses: coexistence of amorphous phases; Modelisation thermodynamique des verres nucleaires: coexistence entre phases amorphes

    Energy Technology Data Exchange (ETDEWEB)

    Adjanor, G

    2007-11-15

    Investigating the stability of borosilicate glasses used in the nuclear industry with respect to phase separation requires to estimate the Gibbs free energies of the various phases appearing in the material. In simulation, using current computational resources, a direct state-sampling of a glassy system with respect to its ensemble statistics is not ergodic and the estimated ensemble averages are not reliable. Our approach consists in generating, at a given cooling rate, a series of quenches, or paths connecting states of the liquid to states of the glass, and then in taking into account the probability to generate the paths leading to the different glassy states in ensembles averages. In this way, we introduce a path ensemble formalism and calculate a Landau free energy associated to a glassy meta-basin. This method was validated by accurately mapping the free energy landscape of a 38-atom glassy cluster. We then applied this approach to the calculation of the Gibbs free energies of binary amorphous Lennard-Jones alloys, and checked the correlation between the observed tendencies to order or to phase separate and the computed Gibbs free energies. We finally computed the driving force to phase separation in a simplified three-oxide nuclear glass modeled by a Born-Mayer-Huggins potential that includes a three-body term, and we compared the estimated quantities to the available experimental data. (author)

  7. Modeling of Transistor's Tracking Behavior in Compact Models

    Directory of Open Access Journals (Sweden)

    Ning Lu

    2011-01-01

    Full Text Available We present a novel method to model the tracking behavior of semiconductor transistors undergoing across-chip variations in a compact Monte Carlo model for SPICE simulations and show an enablement of simultaneous (−1/2 tracking relations among transistors on a chip at any poly density, any gate pitch, and any physical location for the first time. At smaller separations, our modeled tracking relation versus physical location reduces to Pelgrom's characterization on device's distance-dependent mismatch. Our method is very compact, since we do not use a matrix or a set of eigen solutions to represent correlations among transistors.

  8. A Provenance Tracking Model for Data Updates

    Directory of Open Access Journals (Sweden)

    Gabriel Ciobanu

    2012-08-01

    Full Text Available For data-centric systems, provenance tracking is particularly important when the system is open and decentralised, such as the Web of Linked Data. In this paper, a concise but expressive calculus which models data updates is presented. The calculus is used to provide an operational semantics for a system where data and updates interact concurrently. The operational semantics of the calculus also tracks the provenance of data with respect to updates. This provides a new formal semantics extending provenance diagrams which takes into account the execution of processes in a concurrent setting. Moreover, a sound and complete model for the calculus based on ideals of series-parallel DAGs is provided. The notion of provenance introduced can be used as a subjective indicator of the quality of data in concurrent interacting systems.

  9. Resource Tracking Model Updates and Trade Studies

    Science.gov (United States)

    Chambliss, Joe; Stambaugh, Imelda; Moore, Michael

    2016-01-01

    The Resource Tracking Model has been updated to capture system manager and project manager inputs. Both the Trick/General Use Nodal Network Solver Resource Tracking Model (RTM) simulator and the RTM mass balance spreadsheet have been revised to address inputs from system managers and to refine the way mass balance is illustrated. The revisions to the RTM included the addition of a Plasma Pyrolysis Assembly (PPA) to recover hydrogen from Sabatier Reactor methane, which was vented in the prior version of the RTM. The effect of the PPA on the overall balance of resources in an exploration vehicle is illustrated in the increased recycle of vehicle oxygen. Case studies have been run to show the relative effect of performance changes on vehicle resources.

  10. An interface tracking model for droplet electrocoalescence.

    Energy Technology Data Exchange (ETDEWEB)

    Erickson, Lindsay Crowl

    2013-09-01

    This report describes an Early Career Laboratory Directed Research and Development (LDRD) project to develop an interface tracking model for droplet electrocoalescence. Many fluid-based technologies rely on electrical fields to control the motion of droplets, e.g. microfluidic devices for high-speed droplet sorting, solution separation for chemical detectors, and purification of biodiesel fuel. Precise control over droplets is crucial to these applications. However, electric fields can induce complex and unpredictable fluid dynamics. Recent experiments (Ristenpart et al. 2009) have demonstrated that oppositely charged droplets bounce rather than coalesce in the presence of strong electric fields. A transient aqueous bridge forms between approaching drops prior to pinch-off. This observation applies to many types of fluids, but neither theory nor experiments have been able to offer a satisfactory explanation. Analytic hydrodynamic approximations for interfaces become invalid near coalescence, and therefore detailed numerical simulations are necessary. This is a computationally challenging problem that involves tracking a moving interface and solving complex multi-physics and multi-scale dynamics, which are beyond the capabilities of most state-of-the-art simulations. An interface-tracking model for electro-coalescence can provide a new perspective to a variety of applications in which interfacial physics are coupled with electrodynamics, including electro-osmosis, fabrication of microelectronics, fuel atomization, oil dehydration, nuclear waste reprocessing and solution separation for chemical detectors. We present a conformal decomposition finite element (CDFEM) interface-tracking method for the electrohydrodynamics of two-phase flow to demonstrate electro-coalescence. CDFEM is a sharp interface method that decomposes elements along fluid-fluid boundaries and uses a level set function to represent the interface.

  11. Stochastic analysis model for vehicle-track coupled systems subject to earthquakes and track random irregularities

    Science.gov (United States)

    Xu, Lei; Zhai, Wanming

    2017-10-01

    This paper devotes to develop a computational model for stochastic analysis and reliability assessment of vehicle-track systems subject to earthquakes and track random irregularities. In this model, the earthquake is expressed as non-stationary random process simulated by spectral representation and random function, and the track random irregularities with ergodic properties on amplitudes, wavelengths and probabilities are characterized by a track irregularity probabilistic model, and then the number theoretical method (NTM) is applied to effectively select representative samples of earthquakes and track random irregularities. Furthermore, a vehicle-track coupled model is presented to obtain the dynamic responses of vehicle-track systems due to the earthquakes and track random irregularities at time-domain, and the probability density evolution method (PDEM) is introduced to describe the evolutionary process of probability from excitation input to response output by assuming the vehicle-track system as a probabilistic conservative system, which lays the foundation on reliability assessment of vehicle-track systems. The effectiveness of the proposed model is validated by comparing to the results of Monte-Carlo method from statistical viewpoint. As an illustrative example, the random vibrations of a high-speed railway vehicle running on the track slabs excited by lateral seismic waves and track random irregularities are analyzed, from which some significant conclusions can be drawn, e.g., track irregularities will additionally promote the dynamic influence of earthquakes especially on maximum values and dispersion degree of responses; the characteristic frequencies or frequency ranges respectively governed by earthquakes and track random irregularities are greatly different, moreover, the lateral seismic waves will dominate or even change the characteristic frequencies of system responses of some lateral dynamic indices at low frequency.

  12. Modeling the Coupled Chemo-Thermo-Mechanical Behavior of Amorphous Polymer Networks.

    Energy Technology Data Exchange (ETDEWEB)

    Zimmerman, Jonathan A. [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Nguyen, Thao D. [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Xiao, Rui [Sandia National Lab. (SNL-CA), Livermore, CA (United States)

    2015-02-01

    Amorphous polymers exhibit a rich landscape of time-dependent behavior including viscoelasticity, structural relaxation, and viscoplasticity. These time-dependent mechanisms can be exploited to achieve shape-memory behavior, which allows the material to store a programmed deformed shape indefinitely and to recover entirely the undeformed shape in response to specific environmental stimulus. The shape-memory performance of amorphous polymers depends on the coordination of multiple physical mechanisms, and considerable opportunities exist to tailor the polymer structure and shape-memory programming procedure to achieve the desired performance. The goal of this project was to use a combination of theoretical, numerical and experimental methods to investigate the effect of shape memory programming, thermo-mechanical properties, and physical and environmental aging on the shape memory performance. Physical and environmental aging occurs during storage and through exposure to solvents, such as water, and can significantly alter the viscoelastic behavior and shape memory behavior of amorphous polymers. This project – executed primarily by Professor Thao Nguyen and Graduate Student Rui Xiao at Johns Hopkins University in support of a DOE/NNSA Presidential Early Career Award in Science and Engineering (PECASE) – developed a theoretical framework for chemothermo- mechanical behavior of amorphous polymers to model the effects of physical aging and solvent-induced environmental factors on their thermoviscoelastic behavior.

  13. Hydroxylated crystalline edingtonite silica faces as models for the amorphous silica surface

    Energy Technology Data Exchange (ETDEWEB)

    Tosoni, S; Civalleri, B; Ugliengo, P [Dipartimento di Chimica IFM and NIS (Centre of Excellence), Universita di Torino, Via P. Giuria 7, 10125 Torino - ITALY (Italy); Pascale, F [Laboratoire de Cristallographie ed Modelisation des Materiaux Mineraux et Biologiques, UMR-CNRS-7036. Universite Henri Poincare - Nancy I, B.P. 239, 54506 Vandoeuvre-les-Nancy Cedex 05 - FRANCE (France)], E-mail: piero.ugliengo@unito.it

    2008-06-01

    Fully hydroxylated surfaces derived from crystalline edingtonite were adopted to model the variety of sites known to exist at the amorphous silica surface, namely isolated, geminal and interacting silanols. Structures, energetics and vibrational features of the surfaces either bare or in contact with water were modelled at DFT level using the B3LYP functional with a GTO basis set of double-zeta polarized quality using the periodic ab-initio CRYSTAL06 code. Simulated infrared spectra of both dry and water wet edingtonite surfaces were in excellent agreement with the experimental ones recorded on amorphous silica. Water interaction energies were compared with microcalorimetric differential heats of adsorption data showing good agreement, albeit computed ones being slightly underestimated due to the lack of dispersive forces in the B3LYP functional.

  14. Numerically modeling Brownian thermal noise in amorphous and crystalline thin coatings

    Science.gov (United States)

    Lovelace, Geoffrey; Demos, Nicholas; Khan, Haroon

    2018-01-01

    Thermal noise is expected to be one of the noise sources limiting the astrophysical reach of Advanced LIGO (once commissioning is complete) and third-generation detectors. Adopting crystalline materials for thin, reflecting mirror coatings, rather than the amorphous coatings used in current-generation detectors, could potentially reduce thermal noise. Understanding and reducing thermal noise requires accurate theoretical models, but modeling thermal noise analytically is especially challenging with crystalline materials. Thermal noise models typically rely on the fluctuation-dissipation theorem, which relates the power spectral density of the thermal noise to an auxiliary elastic problem. In this paper, we present results from a new, open-source tool that numerically solves the auxiliary elastic problem to compute the Brownian thermal noise for both amorphous and crystalline coatings. We employ the open-source deal.ii and PETSc frameworks to solve the auxiliary elastic problem using a finite-element method, adaptive mesh refinement, and parallel processing that enables us to use high resolutions capable of resolving the thin reflective coating. We verify numerical convergence, and by running on up to hundreds of compute cores, we resolve the coating elastic energy in the auxiliary problem to approximately 0.1%. We compare with approximate analytic solutions for amorphous materials, and we verify that our solutions scale as expected with changing beam size, mirror dimensions, and coating thickness. Finally, we model the crystalline coating thermal noise in an experiment reported by Cole et al (2013 Nat. Photon. 7 644–50), comparing our results to a simpler numerical calculation that treats the coating as an ‘effectively amorphous’ material. We find that treating the coating as a cubic crystal instead of as an effectively amorphous material increases the thermal noise by about 3%. Our results are a step toward better understanding and reducing thermal noise to

  15. Deformation Models Tracking, Animation and Applications

    CERN Document Server

    Torres, Arnau; Gómez, Javier

    2013-01-01

    The computational modelling of deformations has been actively studied for the last thirty years. This is mainly due to its large range of applications that include computer animation, medical imaging, shape estimation, face deformation as well as other parts of the human body, and object tracking. In addition, these advances have been supported by the evolution of computer processing capabilities, enabling realism in a more sophisticated way. This book encompasses relevant works of expert researchers in the field of deformation models and their applications.  The book is divided into two main parts. The first part presents recent object deformation techniques from the point of view of computer graphics and computer animation. The second part of this book presents six works that study deformations from a computer vision point of view with a common characteristic: deformations are applied in real world applications. The primary audience for this work are researchers from different multidisciplinary fields, s...

  16. A comprehensive track model for the improvement of corrugation models

    Science.gov (United States)

    Gómez, J.; Vadillo, E. G.; Santamaría, J.

    2006-06-01

    This paper presents a detailed model of the railway track based on wave propagation, suitable for corrugation studies. The model analyses both the vertical and the transverse dynamics of the track. Using the finite strip method (FSM), only the cross-section of the rail must be meshed, and thus it is not necessary to discretise a whole span in 3D. This model takes into account the discrete nature of the support, introducing concepts pertaining to the theory of periodic structures in the formulation. Wave superposition is enriched taking into account the contribution of residual vectors. In this way, the model obtains accurate results when a finite section of railway track is considered. Results for the infinite track have been compared against those presented by Gry and Müller. Aside from the improvements provided by the model presented in this paper, which Gry's and Müller's models do not contemplate, the results arising from the comparison prove satisfactory. Finally, the calculated receptances are compared against the experimental values obtained by the authors, demonstrating a fair degree of adequacy. Finally, these receptances are used within a linear model of corrugation developed by the authors.

  17. Atomistic models of amorphous polybutadienes; 3 -- Static free volume

    Energy Technology Data Exchange (ETDEWEB)

    Misra, S.; Mattice, W.L. [Univ. of Akron, OH (United States). Inst. of Polymer Science

    1993-12-20

    Atomistic models of polybutadiene have been generated using molecular mechanics and molecular dynamics at a bulk density of 0.89 g cm{sup {minus}3}. Four microstructures formed by cis-1,4-polybutadiene, trans-1,4-polybutadiene, 1,2-polybutadiene, and a random copolymer of the three (55% trans, 35% cis, and 10% vinyl) are analyzed for static free volume. The free volume is determined by hard spherical probes that see the atoms as hard spheres of radii which equal 89% of their van der Waals radii. The total free volume, the free volume distribution, and the shape of the voids are analyzed for all four microstructures. The accessible free volume as a function of the probe size is found to be characteristic of voids in disordered packings of hard spheres. The free volume distributions have some common features across the microstructures. In particular, the free volume distributions as probed by a 1-{angstrom} radius probe show void size concentrations around {approximately}7.5 and 15 {angstrom}{sup 3} (with the exception of trans-polybutadiene, which does not display the latter). The shape factors for all four structures decay to the same asymptotic value of 0.67 {+-} 0.1 over the size range of 0--5 {angstrom}{sup 3}. There is a marked difference in the asphericity and the acylindricity of voids in the four microstructures. Analysis of randomly generated shapes suggests that the voids in the polymer microstructures are mostly elongated in comparison with randomly ``grown`` cavities, probably due to the connectivity of the polymer chains.

  18. The Soft-Confined Method for Creating Molecular Models of Amorphous Polymer Surfaces

    KAUST Repository

    Liu, Hongyi

    2012-02-09

    The goal of this work was to use molecular dynamics (MD) simulations to build amorphous surface layers of polypropylene (PP) and cellulose and to inspect their physical and interfacial properties. A new method to produce molecular models for these surfaces was developed, which involved the use of a "soft" confining layer comprised of a xenon crystal. This method compacts the polymers into a density distribution and a degree of molecular surface roughness that corresponds well to experimental values. In addition, calculated properties such as density, cohesive energy density, coefficient of thermal expansion, and the surface energy agree with experimental values and thus validate the use of soft confining layers. The method can be applied to polymers with a linear backbone such as PP as well as those whose backbones contain rings, such as cellulose. The developed PP and cellulose surfaces were characterized by their interactions with water. It was found that a water nanodroplet spreads on the amorphous cellulose surfaces, but there was no significant change in the dimension of the droplet on the PP surface; the resulting MD water contact angles on PP and amorphous cellulose surfaces were determined to be 106 and 33°, respectively. © 2012 American Chemical Society.

  19. Development of a railway wagon-track interaction model: Case studies on excited tracks

    Science.gov (United States)

    Xu, Lei; Chen, Xianmai; Li, Xuwei; He, Xianglin

    2018-02-01

    In this paper, a theoretical framework for modeling the railway wagon-ballast track interactions is presented, in which the dynamic equations of motion of wagon-track systems are constructed by effectively coupling the linear and nonlinear dynamic characteristics of system components. For the linear components, the energy-variational principle is directly used to derive their dynamic matrices, while for the nonlinear components, the dynamic equilibrium method is implemented to deduce the load vectors, based on which a novel railway wagon-ballast track interaction model is developed, and being validated by comparing with the experimental data measured from a heavy haul railway and another advanced model. With this study, extensive contributions in figuring out the critical speed of instability, limits and localizations of track irregularities over derailment accidents are presented by effectively integrating the dynamic simulation model, the track irregularity probabilistic model and time-frequency analysis method. The proposed approaches can provide crucial information to guarantee the running safety and stability of the wagon-track system when considering track geometries and various running speeds.

  20. An improved likelihood model for eye tracking

    DEFF Research Database (Denmark)

    Hammoud, Riad I.; Hansen, Dan Witzner

    2007-01-01

    While existing eye detection and tracking algorithms can work reasonably well in a controlled environment, they tend to perform poorly under real world imaging conditions where the lighting produces shadows and the person's eyes can be occluded by e.g. glasses or makeup. As a result, pixel clusters...... associated with the eyes tend to be grouped together with background-features. This problem occurs both for eye detection and eye tracking. Problems that especially plague eye tracking include head movement, eye blinking and light changes, all of which can cause the eyes to suddenly disappear. The usual...... approach in such cases is to abandon the tracking routine and re-initialize eye detection. Of course this may be a difficult process due to missed data problem. Accordingly, what is needed is an efficient method of reliably tracking a person's eyes between successively produced video image frames, even...

  1. Models and Algorithms for Tracking Target with Coordinated Turn Motion

    Directory of Open Access Journals (Sweden)

    Xianghui Yuan

    2014-01-01

    Full Text Available Tracking target with coordinated turn (CT motion is highly dependent on the models and algorithms. First, the widely used models are compared in this paper—coordinated turn (CT model with known turn rate, augmented coordinated turn (ACT model with Cartesian velocity, ACT model with polar velocity, CT model using a kinematic constraint, and maneuver centered circular motion model. Then, in the single model tracking framework, the tracking algorithms for the last four models are compared and the suggestions on the choice of models for different practical target tracking problems are given. Finally, in the multiple models (MM framework, the algorithm based on expectation maximization (EM algorithm is derived, including both the batch form and the recursive form. Compared with the widely used interacting multiple model (IMM algorithm, the EM algorithm shows its effectiveness.

  2. Application of partial least-squares (PLS) modeling in quantifying drug crystallinity in amorphous solid dispersions.

    Science.gov (United States)

    Rumondor, Alfred C F; Taylor, Lynne S

    2010-10-15

    Among the different experimental methods that can be used to quantify the evolution of drug crystallinity in polymer-containing amorphous solid dispersions, powder X-ray diffractometry (PXRD) is commonly considered as a frontline method. In order to achieve accurate quantification of the percent drug crystallinity in the system, calibration curves have to be constructed using appropriate calibration samples and calculation methods. This can be non-trivial in the case of partially crystalline solid dispersions where the calibration samples must capture the multiphase nature of the systems and the mathematical model must be robust enough to accommodate subtle and not so subtle changes in the diffractograms. The purpose of this study was to compare two different calculation and model-building methods to quantify the proportion of crystalline drug in amorphous solid dispersions containing different ratios of drug and amorphous polymer. The first method involves predicting the % drug crystallinity from the ratio of the area underneath the Bragg peaks to total area of the diffractogram. The second method is multivariate analysis using a Partial Least-Squares (PLS) multivariate regression method. It was found that PLS analysis provided far better accuracy and prediction of % drug crystallinity in the sample. Through the application of PLS, root-mean-squared error of estimation (RMSEE) values of 2.2%, 1.9%, and 4.7% drug crystallinity was achieved for samples containing 25%, 50%, and 75% polymer, respectively, compared to values of 11.2%, 17.0%, and 23.6% for the area model. In addition, construction of a PLS model enables further analysis of the data, including identification of outliers and non-linearity in the data, as well as insight into which factors are most important to correlate PXRD diffractograms with % crystallinity of the drug through analysis of the loadings. Copyright 2010 Elsevier B.V. All rights reserved.

  3. Robust Visual Tracking via Exclusive Context Modeling

    KAUST Repository

    Zhang, Tianzhu

    2015-02-09

    In this paper, we formulate particle filter-based object tracking as an exclusive sparse learning problem that exploits contextual information. To achieve this goal, we propose the context-aware exclusive sparse tracker (CEST) to model particle appearances as linear combinations of dictionary templates that are updated dynamically. Learning the representation of each particle is formulated as an exclusive sparse representation problem, where the overall dictionary is composed of multiple {group} dictionaries that can contain contextual information. With context, CEST is less prone to tracker drift. Interestingly, we show that the popular L₁ tracker [1] is a special case of our CEST formulation. The proposed learning problem is efficiently solved using an accelerated proximal gradient method that yields a sequence of closed form updates. To make the tracker much faster, we reduce the number of learning problems to be solved by using the dual problem to quickly and systematically rank and prune particles in each frame. We test our CEST tracker on challenging benchmark sequences that involve heavy occlusion, drastic illumination changes, and large pose variations. Experimental results show that CEST consistently outperforms state-of-the-art trackers.

  4. Density model for medium range order in amorphous materials: application to small angle scattering

    International Nuclear Information System (INIS)

    Boucher, B.; Tournarie, M.; Chieux, P.; Convert, P.

    1983-06-01

    We consider a family of randomly spaced parallel planes, each plane dressed with a density function, h(x), where x is the distance from the plane. An expression for the volume scattering power from a system of N such families with random orientations in space is derived from Fourier transform of h(x), which can subsequently be determined from experimental observations. This density model is used to interpret the small angle neutron scattering (SANS) results for the amorphous alloy TbCusub(3.54)

  5. Multi-Complementary Model for Long-Term Tracking.

    Science.gov (United States)

    Zhang, Deng; Zhang, Junchang; Xia, Chenyang

    2018-02-09

    In recent years, video target tracking algorithms have been widely used. However, many tracking algorithms do not achieve satisfactory performance, especially when dealing with problems such as object occlusions, background clutters, motion blur, low illumination color images, and sudden illumination changes in real scenes. In this paper, we incorporate an object model based on contour information into a Staple tracker that combines the correlation filter model and color model to greatly improve the tracking robustness. Since each model is responsible for tracking specific features, the three complementary models combine for more robust tracking. In addition, we propose an efficient object detection model with contour and color histogram features, which has good detection performance and better detection efficiency compared to the traditional target detection algorithm. Finally, we optimize the traditional scale calculation, which greatly improves the tracking execution speed. We evaluate our tracker on the Object Tracking Benchmarks 2013 (OTB-13) and Object Tracking Benchmarks 2015 (OTB-15) benchmark datasets. With the OTB-13 benchmark datasets, our algorithm is improved by 4.8%, 9.6%, and 10.9% on the success plots of OPE, TRE and SRE, respectively, in contrast to another classic LCT (Long-term Correlation Tracking) algorithm. On the OTB-15 benchmark datasets, when compared with the LCT algorithm, our algorithm achieves 10.4%, 12.5%, and 16.1% improvement on the success plots of OPE, TRE, and SRE, respectively. At the same time, it needs to be emphasized that, due to the high computational efficiency of the color model and the object detection model using efficient data structures, and the speed advantage of the correlation filters, our tracking algorithm could still achieve good tracking speed.

  6. Model based rapid maximum power point tracking for photovoltaic systems

    International Nuclear Information System (INIS)

    Tsang, K.M.; Chan, W.L.

    2013-01-01

    Highlights: • A novel approach for tracking the maximum power point of photovoltaic systems. • Very fast tracking response with less steady state oscillations in tracking the maximum power point. • Orthogonal least squares estimation algorithm coupled with the forward searching algorithm is applied. - Abstract: This paper presents a novel approach for tracking the maximum power point of photovoltaic (PV) systems so as to extract maximum available power from PV modules. Unlike conventional methods, a very fast tracking response with virtually no steady state oscillations is able to obtain in tracking the maximum power point. To apply the proposed method, firstly, output voltages, output currents under different conditions and temperatures of a PV module are collected for the fitting of environmental invariant nonlinear model for the PV system. Orthogonal least squares estimation algorithm coupled with the forward searching algorithm is applied to sort through all possible candidate terms resulted from the expansion of a polynomial model and to come up with a parsimonious model for the PV system. It is not necessary to test all PV modules as the resultant model is valid for other modules. The power delivered by the PV system can be derived from the fitted model and the maximum power point for the PV system at any working conditions can be obtained from the fitted model. Consequently, rapid maximum power point tracking could be achieved. Experimental results are included to demonstrate the effectiveness of the fitted model in maximum power point tracking

  7. Empty tracks optimization based on Z-Map model

    Science.gov (United States)

    Liu, Le; Yan, Guangrong; Wang, Zaijun; Zang, Genao

    2017-12-01

    For parts with many features, there are more empty tracks during machining. If these tracks are not optimized, the machining efficiency will be seriously affected. In this paper, the characteristics of the empty tracks are studied in detail. Combining with the existing optimization algorithm, a new tracks optimization method based on Z-Map model is proposed. In this method, the tool tracks are divided into the unit processing section, and then the Z-Map model simulation technique is used to analyze the order constraint between the unit segments. The empty stroke optimization problem is transformed into the TSP with sequential constraints, and then through the genetic algorithm solves the established TSP problem. This kind of optimization method can not only optimize the simple structural parts, but also optimize the complex structural parts, so as to effectively plan the empty tracks and greatly improve the processing efficiency.

  8. Device and material characterization and analytic modeling of amorphous silicon thin film transistors

    Science.gov (United States)

    Slade, Holly Claudia

    Hydrogenated amorphous silicon thin film transistors (TFTs) are now well-established as switching elements for a variety of applications in the lucrative electronics market, such as active matrix liquid crystal displays, two-dimensional imagers, and position-sensitive radiation detectors. These applications necessitate the development of accurate characterization and simulation tools. The main goal of this work is the development of a semi- empirical, analytical model for the DC and AC operation of an amorphous silicon TFT for use in a manufacturing facility to improve yield and maintain process control. The model is physically-based, in order that the parameters scale with gate length and can be easily related back to the material and device properties. To accomplish this, extensive experimental data and 2D simulations are used to observe and quantify non- crystalline effects in the TFTs. In particular, due to the disorder in the amorphous network, localized energy states exist throughout the band gap and affect all regimes of TFT operation. These localized states trap most of the free charge, causing a gate-bias-dependent field effect mobility above threshold, a power-law dependence of the current on gate bias below threshold, very low leakage currents, and severe frequency dispersion of the TFT gate capacitance. Additional investigations of TFT instabilities reveal the importance of changes in the density of states and/or back channel conduction due to bias and thermal stress. In the above threshold regime, the model is similar to the crystalline MOSFET model, considering the drift component of free charge. This approach uses the field effect mobility to take into account the trap states and must utilize the correct definition of threshold voltage. In the below threshold regime, the density of deep states is taken into account. The leakage current is modeled empirically, and the parameters are temperature dependent to 150oC. The capacitance of the TFT can be

  9. Effect of heating rate and kinetic model selection on activation energy of nonisothermal crystallization of amorphous felodipine.

    Science.gov (United States)

    Chattoraj, Sayantan; Bhugra, Chandan; Li, Zheng Jane; Sun, Changquan Calvin

    2014-12-01

    The nonisothermal crystallization kinetics of amorphous materials is routinely analyzed by statistically fitting the crystallization data to kinetic models. In this work, we systematically evaluate how the model-dependent crystallization kinetics is impacted by variations in the heating rate and the selection of the kinetic model, two key factors that can lead to significant differences in the crystallization activation energy (Ea ) of an amorphous material. Using amorphous felodipine, we show that the Ea decreases with increase in the heating rate, irrespective of the kinetic model evaluated in this work. The model that best describes the crystallization phenomenon cannot be identified readily through the statistical fitting approach because several kinetic models yield comparable R(2) . Here, we propose an alternate paired model-fitting model-free (PMFMF) approach for identifying the most suitable kinetic model, where Ea obtained from model-dependent kinetics is compared with those obtained from model-free kinetics. The most suitable kinetic model is identified as the one that yields Ea values comparable with the model-free kinetics. Through this PMFMF approach, nucleation and growth is identified as the main mechanism that controls the crystallization kinetics of felodipine. Using this PMFMF approach, we further demonstrate that crystallization mechanism from amorphous phase varies with heating rate. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association.

  10. Model-Based Real-Time Head Tracking

    Directory of Open Access Journals (Sweden)

    Ström Jacob

    2002-01-01

    Full Text Available This paper treats real-time tracking of a human head using an analysis by synthesis approach. The work is based on the Structure from Motion (SfM algorithm from Azarbayejani and Pentland (1995. We will analyze the convergence properties of the SfM algorithm for planar objects, and extend it to handle new points. The extended algorithm is then used for head tracking. The system tracks feature points in the image using a texture mapped three-dimensional model of the head. The texture is updated adaptively so that points in the ear region can be tracked when the user′s head is rotated far, allowing out-of-plane rotation of up to without losing track. The covariance of the - and the -coordinates are estimated and forwarded to the Kalman filter, making the tracker robust to occlusion. The system automatically detects tracking failure and reinitializes the algorithm using information gathered in the original initialization process.

  11. Aging and linear response in the Hébraud-Lequeux model for amorphous rheology

    Science.gov (United States)

    Sollich, Peter; Olivier, Julien; Bresch, Didier

    2017-04-01

    We analyse the aging dynamics of the Hébraud-Lequeux model, a self-consistent stochastic model for the evolution of local stress in an amorphous material. We show that the model exhibits initial-condition dependent freezing: the stress diffusion constant decays with time as D˜ 1/{{t}2} during aging so that the cumulative amount of memory that can be erased, which is given by the time integral of D(t), is finite. Accordingly the shear stress relaxation function, which we determine in the long-time regime, only decays to a plateau and becomes progressively elastic as the system ages. The frequency-dependent shear modulus exhibits a corresponding overall decay of the dissipative part with system age, while the characteristic relaxation times scale linearly with age as expected.

  12. Model tracking controller design of robot manipulator system with disturbances

    Directory of Open Access Journals (Sweden)

    Dazhong Wang

    2015-06-01

    Full Text Available In the model tracking control of robot manipulator system, the treatment of nonlinear uncertainty in the system has always been an active research field. This article establishes a kinetic equation for robot manipulator system based on Lagrange equation and proposes a model tracking control system based on differential divisor. On this basis, this article proposes a model tracking control scheme for robot manipulator systems with disturbances. The proposed scheme is robust stable under the external disturbances. At last, the system simulation approach is employed to verify the effectiveness of this scheme on robot manipulator control.

  13. Track structure model of cell damage in space flight

    Science.gov (United States)

    Katz, Robert; Cucinotta, Francis A.; Wilson, John W.; Shinn, Judy L.; Ngo, Duc M.

    1992-01-01

    The phenomenological track-structure model of cell damage is discussed. A description of the application of the track-structure model with the NASA Langley transport code for laboratory and space radiation is given. Comparisons to experimental results for cell survival during exposure to monoenergetic, heavy-ion beams are made. The model is also applied to predict cell damage rates and relative biological effectiveness for deep-space exposures.

  14. Surface Complexation Model for Strontium Sorption to Amorphous Silica and Goethite

    Energy Technology Data Exchange (ETDEWEB)

    Carroll, S; Robers, S; Criscenti, L; O' Day, P

    2007-11-30

    Strontium sorption to amorphous silica and goethite was measured as a function of pH and dissolved strontium and carbonate concentrations at 25 C. Strontium sorption gradually increases from 0 to 100% from pH 6 to 10 for both phases and requires multiple outer-sphere surface complexes to fit the data. All data are modeled using the triple layer model and the site-occupancy standard state; unless stated otherwise all strontium complexes are mononuclear. Strontium sorption to amorphous silica in the presence and absence of dissolved carbonate can be fit with tetradentate Sr{sup 2+} and SrOH{sup +} complexes on the {beta}-plane and a monodentate Sr{sup 2+} complex on the diffuse plane to account for strontium sorption at low ionic strength. Strontium sorption to goethite in the absence of dissolved carbonate can be fit with monodentate and tetradentate SrOH{sup +} complexes and a tetradentate binuclear Sr{sup 2+} species on the {beta}-plane. The binuclear complex is needed to account for enhanced sorption at high strontium surface loadings. In the presence of dissolved carbonate additional monodentate Sr{sup 2+} and SrOH{sup +} carbonate surface complexes on the {beta}-plane are needed to fit strontium sorption to goethite. Modeling strontium sorption as outer-sphere complexes is consistent with quantitative analysis of extended X-ray absorption fine structure (EXAFS) on selected sorption samples that show a single first shell of oxygen atoms around strontium indicating hydrated surface complexes at the amorphous silica and goethite surfaces. Strontium surface complexation equilibrium constants determined in this study combined with other alkaline earth surface complexation constants are used to recalibrate a predictive model based on Born solvation and crystal-chemistry theory. The model is accurate to about 0.7 log K units. More studies are needed to determine the dependence of alkaline earth sorption on ionic strength and dissolved carbonate and sulfate

  15. Surface complexation model for strontium sorption to amorphous silica and goethite

    Directory of Open Access Journals (Sweden)

    Criscenti Louise J

    2008-01-01

    Full Text Available Abstract Strontium sorption to amorphous silica and goethite was measured as a function of pH and dissolved strontium and carbonate concentrations at 25°C. Strontium sorption gradually increases from 0 to 100% from pH 6 to 10 for both phases and requires multiple outer-sphere surface complexes to fit the data. All data are modeled using the triple layer model and the site-occupancy standard state; unless stated otherwise all strontium complexes are mononuclear. Strontium sorption to amorphous silica in the presence and absence of dissolved carbonate can be fit with tetradentate Sr2+ and SrOH+ complexes on the β-plane and a monodentate Sr2+complex on the diffuse plane to account for strontium sorption at low ionic strength. Strontium sorption to goethite in the absence of dissolved carbonate can be fit with monodentate and tetradentate SrOH+ complexes and a tetradentate binuclear Sr2+ species on the β-plane. The binuclear complex is needed to account for enhanced sorption at hgh strontium surface loadings. In the presence of dissolved carbonate additional monodentate Sr2+ and SrOH+ carbonate surface complexes on the β-plane are needed to fit strontium sorption to goethite. Modeling strontium sorption as outer-sphere complexes is consistent with quantitative analysis of extended X-ray absorption fine structure (EXAFS on selected sorption samples that show a single first shell of oxygen atoms around strontium indicating hydrated surface complexes at the amorphous silica and goethite surfaces. Strontium surface complexation equilibrium constants determined in this study combined with other alkaline earth surface complexation constants are used to recalibrate a predictive model based on Born solvation and crystal-chemistry theory. The model is accurate to about 0.7 log K units. More studies are needed to determine the dependence of alkaline earth sorption on ionic strength and dissolved carbonate and sulfate concentrations for the development of

  16. Portfolio optimization for index tracking modelling in Malaysia stock market

    Science.gov (United States)

    Siew, Lam Weng; Jaaman, Saiful Hafizah; Ismail, Hamizun

    2016-06-01

    Index tracking is an investment strategy in portfolio management which aims to construct an optimal portfolio to generate similar mean return with the stock market index mean return without purchasing all of the stocks that make up the index. The objective of this paper is to construct an optimal portfolio using the optimization model which adopts regression approach in tracking the benchmark stock market index return. In this study, the data consists of weekly price of stocks in Malaysia market index which is FTSE Bursa Malaysia Kuala Lumpur Composite Index from January 2010 until December 2013. The results of this study show that the optimal portfolio is able to track FBMKLCI Index at minimum tracking error of 1.0027% with 0.0290% excess mean return over the mean return of FBMKLCI Index. The significance of this study is to construct the optimal portfolio using optimization model which adopts regression approach in tracking the stock market index without purchasing all index components.

  17. Characterizing and Modeling Transient Photoconductivity in Amorphous In-Ga-Zn-O Thin Films

    Science.gov (United States)

    Luo, Jiajun

    capturing the initial transients in all samples with high time-resolution. While many previous reports analyzed non-exponential transients by assuming the transients to follow certain function forms, this work introduces a distributed time constant analysis that can be applied to any relaxation response. By transferring the transient response as a function of log-scale time, any relaxation response can be represented as the convolution of a time constant distribution. Therefore, the minimum measurement duration to correctly characterize the response is identified as the inflection point on a semi-log plot versus log-scale time. With the visual features on the semi-log plot, a method to estimate the entire distribution spectrum is also introduced. This allows reasonable estimation of the asymptotic response value, which cannot be directly measured in systems involving large time constants. In the a-IGZO system, the transient photoresponse fits best to a stretched exponential function. This work discusses the applications and properties of the stretched exponential function. Two contrasting physical explanations to the stretched exponential behavior, the distributed activation energy model and the continuous-time random walk model, are discussed. While the distributed activation energy model fails to explain why an asymmetric activation energy distribution appears universally in many distinct systems, the continuous-time random walk model explains the stretched exponential behavior as arising from an exponential tail of activation energies, which fits the disordered nature of amorphous materials. Based on the continuous-time random walk model, a microscopic photoresponse mechanism compatible with the observed stretched exponential transient is proposed for the a-IGZO system.

  18. Experimental and modelling studies of the shape memory properties of amorphous polymer network composites

    International Nuclear Information System (INIS)

    Arrieta, J S; Diani, J; Gilormini, P

    2014-01-01

    Shape memory polymer composites (SMPCs) have become an important way to leverage improvements in the development of applications featuring shape memory polymers (SMPs). In this study, an amorphous SMP matrix has been filled with different types of reinforcements. An experimental set of results is presented and then compared to three-dimensional (3D) finite-element simulations. Thermomechanical shape memory cycles were performed in uniaxial tension. The fillers effect was studied in stress-free and constrained-strain recoveries. Experimental observations indicate complete shape recovery and put in evidence the increased sensitivity of constrained length stress recoveries to the heating ramp on the tested composites. The simulations reproduced a simplified periodic reinforced composite and used a model for the matrix material that has been previously tested on regular SMPs. The latter combines viscoelasticity at finite strain and time-temperature superposition. The simulations easily allow representation of the recovery properties of a reinforced SMP. (paper)

  19. An equalised global graphical model-based approach for multi-camera object tracking

    OpenAIRE

    Chen, Weihua; Cao, Lijun; Chen, Xiaotang; Huang, Kaiqi

    2015-01-01

    Non-overlapping multi-camera visual object tracking typically consists of two steps: single camera object tracking and inter-camera object tracking. Most of tracking methods focus on single camera object tracking, which happens in the same scene, while for real surveillance scenes, inter-camera object tracking is needed and single camera tracking methods can not work effectively. In this paper, we try to improve the overall multi-camera object tracking performance by a global graph model with...

  20. Predictive model of the optical response of amorphous WO3 to ion intercalation

    Science.gov (United States)

    Lehan, J. P.; Yu, P. C.; Backfisch, D. L.; Chambers, J. P.

    2002-10-01

    The optical response of an amorphous tungsten oxide half cell upon varying degrees of protenation is examined. First, the indium tin oxide transparent conductor's dielectric function is determined from a parameterized version of the ionized impurity scattering model of Hamberg and Granqvist [I. Hamberg and C. G. Granqvist, Appl. Phys. Lett. 44, 721 (1984)]. Then the tungsten oxide data are interpreted using two theoretical optical dispersion formulas. The first is the polaron conductivity theory of Reik and Reese [H. G. Reik and D. Reese, J. Phys. Chem. Solids 28, 581 (1967)] and the second is the parametric semiconductor model of Johs et al. [B. Johs et al., Thin Solid Films 313-314, 137 (1998)]. It is found that the parametric semiconductor model is able to reproduce the measured optical spectra extremely well. The resulting set of dielectric functions is interpreted in terms of the intercalated charge. An empirical model is constructed to explain the observed behavior of the imaginary part of the dielectric function, which should be appropriate for device modeling. The real part of the dielectric function is then readily determined by application of the Kramers-Krönig relations, which are inherent to the parametric semiconductor model.

  1. RAILWAY TRACK REPRESENTATION IN MATHEMATICAL MODEL OF VEHICLES MOVEMENT

    Directory of Open Access Journals (Sweden)

    M. B. Kurhan

    2017-12-01

    Full Text Available Purpose. The tasks of modeling the interaction of track and rolling stock are basic ones for most areas of mo-dern scientific research of railway transport. The compilation of the model by the principle of Lagrange d'Alembert has found a very wide application for solving the problems of rolling stock dynamics. Representation of the railway track in the model of crew movement can be implemented in several ways, which, among other things, will differ in detail. The purpose of this work is to create a methodology for representing the railway track in mathematical mo-dels of interaction with rolling stock and obtaining practical results for different characteristics and design of the track and the level of maximum speed. Methodology. The problem consists of determining such characteristics of the path as the reduced mass, the stiffness coefficient, and the dissipation coefficient. As a tool for solving this problem it was used the model of the stress-strain behavior of the railway track based on the joint use of the elastic wave propagation equations to describe the geometry of the outline of the part of the system space that is involved in the interaction at a given time and the equations of dynamic equilibrium of its deformation. This makes it possible to take into account the dynamics of the deflection of the under-rail base, which is especially important for the conditions of passenger traffic, which can be carried out at high speed. Findings. Theoretically justified stiffness and dissipation coefficients of the railway track for calculating the dynamics of rolling stock in modern models based on systems of equations in accordance with the Lagrange d'Alembert principle are obtained. The established va-lues, in contrast to those given in other sources, have a reasonable dependence on the design of the path and the speed of movement. Originality. The approaches of railroad track representation in models of rolling stock described by systems of

  2. Mathematical modeling of bacterial track-altering motors: Track cleaving through burnt-bridge ratchets.

    Science.gov (United States)

    Shtylla, Blerta; Keener, James P

    2015-04-01

    The generation of directed movement of cellular components frequently requires the rectification of Brownian motion. Molecular motor enzymes that use ATP to walk on filamentous tracks are typically involved in cell transport, however, a track-altering motor can arise when an enzyme interacts with and alters its track. In Caulobacter crescentus and other bacteria, an active DNA partitioning (Par) apparatus is employed to segregate replicated chromosome regions to specific locations in dividing cells. The Par apparatus is composed of two proteins: ParA, an ATPase that can form polymeric structures on the nucleoid, and ParB, a protein that can bind and destabilize ParA structures. It has been proposed that the ParB-mediated alteration of ParA structures could be responsible for generating the directed movement of DNA during bacterial division. How precisely these actions are coordinated and translated into directed movement is not clear. In this paper we consider the C. crescentus segregation apparatus as an example of a track altering motor that operates using a so-called burnt-bridge mechanism. We develop and analyze mathematical models that examine how diffusion and ATP-hydrolysis-mediated monomer removal (or cleaving) can be combined to generate directed movement. Using a mean first passage approach, we analytically calculate the effective ParA track-cleaving velocities, effective diffusion coefficient, and other higher moments for the movement a ParB protein cluster that breaks monomers away at random locations on a single ParA track. Our model results indicate that cleaving velocities and effective diffusion constants are sensitive to ParB-induced ATP hydrolysis rates. Our analytical results are in excellent agreement with stochastic simulation results.

  3. Amorphous magnetism

    International Nuclear Information System (INIS)

    Rechenberg, H.R.

    1984-01-01

    The consequences of disorder on magnetic properties of solids are examined. In this context the word 'disorder' is not synonimous of structural amorphicity; chemical disorder can be achieved e.g. by randomly diffusing magnetic atoms on a nonmagnetic crystalline lattice. The name Amorphous Magnetism must be taken in a broad sense. (Author) [pt

  4. Group Targets Tracking Using Multiple Models GGIW-CPHD Based on Best-Fitting Gaussian Approximation and Strong Tracking Filter

    Directory of Open Access Journals (Sweden)

    Yun Wang

    2016-01-01

    Full Text Available Gamma Gaussian inverse Wishart cardinalized probability hypothesis density (GGIW-CPHD algorithm was always used to track group targets in the presence of cluttered measurements and missing detections. A multiple models GGIW-CPHD algorithm based on best-fitting Gaussian approximation method (BFG and strong tracking filter (STF is proposed aiming at the defect that the tracking error of GGIW-CPHD algorithm will increase when the group targets are maneuvering. The best-fitting Gaussian approximation method is proposed to implement the fusion of multiple models using the strong tracking filter to correct the predicted covariance matrix of the GGIW component. The corresponding likelihood functions are deduced to update the probability of multiple tracking models. From the simulation results we can see that the proposed tracking algorithm MM-GGIW-CPHD can effectively deal with the combination/spawning of groups and the tracking error of group targets in the maneuvering stage is decreased.

  5. KONTROL TRACKING FUZZY MENGGUNAKAN MODEL FOLLOWING UNTUK SISTEM PENDULUM KERETA

    Directory of Open Access Journals (Sweden)

    Jimmy Hennyta Satya Putra

    2017-01-01

    Full Text Available Sistem pendulum kereta memiliki karakteristik yang tidak stabil dan nonlinear. Pada Tugas Akhir ini membahas tentang kontrol tracking dengan menggunakan struktur kontrol berbasis model following. Permasalahan dalam desain struktur kontrol tracking pada sistem pendulum kereta ini adalah bagaimana membuat posisi kereta dapat mengikuti sinyal referensi dengan tetap mempertahankan batang pendulum pada posisi equilibriumnya yaitu pada sudut nol radian. Model nonlinear dari sistem pendulum kereta direpresentasikan sebagai model fuzzy Takagi-Sugeno. Berdasarkan model tersebut, aturan kontroler disusun menggunakan konsep Parallel Distributed Compensation (PDC berbasis teknik kontrol optimal. Hasil simulasi dan implementasi menunjukkan bahwa posisi kereta dapat mengikuti sinyal referensi tanpa adanya beda fasa antara respon posisi kereta terhadap sinyal referensi. Sinyal referensi sinus memberikan performansi tracking terbaik, dengan Integral Absolute Error (IAE terkecil diantara sinyal referensi lain, yaitu pada simulasi sebesar 0,2622 dan pada implementasi sebesar 0,8477

  6. Particle tracking in sophisticated CAD models for simulation purposes

    International Nuclear Information System (INIS)

    Sulkimo, J.; Vuoskoski, J.

    1995-01-01

    The transfer of physics detector models from computer aided design systems to physics simulation packages like GEANT suffers from certain limitations. In addition, GEANT is not able to perform particle tracking in CAD models. We describe an application which is able to perform particle tracking in boundary models constructed in CAD systems. The transfer file format used is the new international standard, STEP. The design and implementation of the application was carried out using object-oriented techniques. It will be integrated in the future object-oriented version of GEANT. (orig.)

  7. Continuum modeling of twinning, amorphization, and fracture: theory and numerical simulations

    Science.gov (United States)

    Clayton, J. D.; Knap, J.

    2017-12-01

    A continuum mechanical theory is used to model physical mechanisms of twinning, solid-solid phase transformations, and failure by cavitation and shear fracture. Such a sequence of mechanisms has been observed in atomic simulations and/or experiments on the ceramic boron carbide. In the present modeling approach, geometric quantities such as the metric tensor and connection coefficients can depend on one or more director vectors, also called internal state vectors. After development of the general nonlinear theory, a first problem class considers simple shear deformation of a single crystal of this material. For homogeneous fields or stress-free states, algebraic systems or ordinary differential equations are obtained that can be solved by numerical iteration. Results are in general agreement with atomic simulation, without introduction of fitted parameters. The second class of problems addresses the more complex mechanics of heterogeneous deformation and stress states involved in deformation and failure of polycrystals. Finite element calculations, in which individual grains in a three-dimensional polycrystal are fully resolved, invoke a partially linearized version of the theory. Results provide new insight into effects of crystal morphology, activity or inactivity of different inelasticity mechanisms, and imposed deformation histories on strength and failure of the aggregate under compression and shear. The importance of incorporation of inelastic shear deformation in realistic models of amorphization of boron carbide is noted, as is a greater reduction in overall strength of polycrystals containing one or a few dominant flaws rather than many diffusely distributed microcracks.

  8. Continuum modeling of twinning, amorphization, and fracture: theory and numerical simulations

    Science.gov (United States)

    Clayton, J. D.; Knap, J.

    2018-03-01

    A continuum mechanical theory is used to model physical mechanisms of twinning, solid-solid phase transformations, and failure by cavitation and shear fracture. Such a sequence of mechanisms has been observed in atomic simulations and/or experiments on the ceramic boron carbide. In the present modeling approach, geometric quantities such as the metric tensor and connection coefficients can depend on one or more director vectors, also called internal state vectors. After development of the general nonlinear theory, a first problem class considers simple shear deformation of a single crystal of this material. For homogeneous fields or stress-free states, algebraic systems or ordinary differential equations are obtained that can be solved by numerical iteration. Results are in general agreement with atomic simulation, without introduction of fitted parameters. The second class of problems addresses the more complex mechanics of heterogeneous deformation and stress states involved in deformation and failure of polycrystals. Finite element calculations, in which individual grains in a three-dimensional polycrystal are fully resolved, invoke a partially linearized version of the theory. Results provide new insight into effects of crystal morphology, activity or inactivity of different inelasticity mechanisms, and imposed deformation histories on strength and failure of the aggregate under compression and shear. The importance of incorporation of inelastic shear deformation in realistic models of amorphization of boron carbide is noted, as is a greater reduction in overall strength of polycrystals containing one or a few dominant flaws rather than many diffusely distributed microcracks.

  9. Hydrogen in amorphous silicon

    International Nuclear Information System (INIS)

    Peercy, P.S.

    1980-01-01

    The structural aspects of amorphous silicon and the role of hydrogen in this structure are reviewed with emphasis on ion implantation studies. In amorphous silicon produced by Si ion implantation of crystalline silicon, the material reconstructs into a metastable amorphous structure which has optical and electrical properties qualitatively similar to the corresponding properties in high-purity evaporated amorphous silicon. Hydrogen studies further indicate that these structures will accomodate less than or equal to 5 at.% hydrogen and this hydrogen is bonded predominantly in a monohydride (SiH 1 ) site. Larger hydrogen concentrations than this can be achieved under certain conditions, but the excess hydrogen may be attributed to defects and voids in the material. Similarly, glow discharge or sputter deposited amorphous silicon has more desirable electrical and optical properties when the material is prepared with low hydrogen concentration and monohydride bonding. Results of structural studies and hydrogen incorporation in amorphous silicon were discussed relative to the different models proposed for amorphous silicon

  10. The Sport Education Model: A Track and Field Unit Application

    Science.gov (United States)

    O'Neil, Kason; Krause, Jennifer M.

    2016-01-01

    Track and field is a traditional instructional unit often taught in secondary physical education settings due to its history, variety of events, and potential for student interest. This article provides an approach to teaching this unit using the sport education model (SEM) of instruction, which has traditionally been presented as a model for team…

  11. Modeling and Velocity Tracking Control for Tape Drive System ...

    African Journals Online (AJOL)

    The objectives of this paper are to formulate mathematical model for the tape drive system (TDS) by designing velocity tracking controller using physical laws. A Matlab function script and Simulink model were developed in Matlab and Simulink environment. The result of the study revealed that 7.07, 8 and 10 of koln values ...

  12. Modeling and Velocity Tracking Control for Tape Drive System ...

    African Journals Online (AJOL)

    ADOWIE PERE

    2018-03-23

    Mar 23, 2018 ... ABSTRACT: The objectives of this paper are to formulate mathematical model for the tape drive system (TDS) by designing velocity tracking controller using physical laws. A Matlab function script and Simulink model were developed in Matlab and Simulink environment. The result of the study revealed that ...

  13. Model Predictive Control for Offset-Free Reference Tracking

    Czech Academy of Sciences Publication Activity Database

    Belda, Květoslav

    2016-01-01

    Roč. 5, č. 1 (2016), s. 8-13 ISSN 1805-3386 Institutional support: RVO:67985556 Keywords : offset-free reference tracking * predictive control * ARX model * state-space model * multi-input multi-output system * robotic system * mechatronic system Subject RIV: BC - Control Systems Theory http://library.utia.cas.cz/separaty/2016/AS/belda-0458355.pdf

  14. Critical behavior in a random field classical Heisenberg model for amorphous systems

    International Nuclear Information System (INIS)

    Albuquerque, Douglas F. de; Alves, Sandro Roberto L.; Arruda, Alberto S. de

    2005-01-01

    By using the differential operator technique and the effective field theory scheme, the critical behavior of amorphous classical Heisenberg ferromagnet of spin-1/2 in a random field is studied. The phase diagram in the T-H and T-α planes on a simple cubic lattice for a cluster with two spins is obtained. Tricritical points, reentrant phenomena and influence of the random field and amorphization on the transition temperature are discussed

  15. PENGEMBANGAN MODEL TRACKING DAN TRACING DALAM DISTRIBUSI KOMODITI PERTANIAN

    Directory of Open Access Journals (Sweden)

    Yandra Rahadian Perdana

    2011-06-01

    Full Text Available Kegagalan distribusi komoditi pertanian dapat berdampak pada penurunan dan kehilangan nilai baik secara kualitas dan kuantitas karena suatu perubahan dimensi waktu-jarak atau suhu serta sarana pengangkutan dalam setiap mata rantai aktivitas distribusi. Model tracking dan tracing system dapat menjadi strategi untuk menjamin keberhasilan distribusi komoditi pertanian secara tepat baik kuantitas maupun kualitas. Model tracking dan tracing komoditi pertanian adalah sebuah sistem proaktif yang real time yang dilengkapi dengan komponen pendukung proses distribusi dengan data yang akurat, terpercaya, berguna, dan cepat dengan memberikan informasi posisi barang atau sarana moda transportasinya.

  16. Amorphous track modelling of luminescence detector efficiency in proton and carbon beams

    DEFF Research Database (Denmark)

    Greilich, Steffen; Grzanka, Leszek; Bassler, Niels

    assumptions in a variety of detectors. The library also includes simple particle transportation or can be interfaced to external transport codes. We applied our code to RL and OSL data from fiber-coupled Al2O3:C-detectors in a proton (nominal energies 10 MeV to 60 MeV) and a carbon beam (270 MeV/u). Results...

  17. Amorphous nanophotonics

    CERN Document Server

    Scharf, Toralf

    2013-01-01

    This book represents the first comprehensive overview over amorphous nano-optical and nano-photonic systems. Nanophotonics is a burgeoning branch of optics that enables many applications by steering the mould of light on length scales smaller than the wavelength with devoted nanostructures. Amorphous nanophotonics exploits self-organization mechanisms based on bottom-up approaches to fabricate nanooptical systems. The resulting structures presented in the book are characterized by a deterministic unit cell with tailored geometries; but their spatial arrangement is not controlled. Instead of periodic, the structures appear either amorphous or random. The aim of this book is to discuss all aspects related to observable effects in amorphous nanophotonic material and aspects related to their design, fabrication, characterization and integration into applications. The book has an interdisciplinary nature with contributions from scientists in physics, chemistry and materials sciences and sheds light on the topic fr...

  18. Multi-Topic Tracking Model for dynamic social network

    Science.gov (United States)

    Li, Yuhua; Liu, Changzheng; Zhao, Ming; Li, Ruixuan; Xiao, Hailing; Wang, Kai; Zhang, Jun

    2016-07-01

    The topic tracking problem has attracted much attention in the last decades. However, existing approaches rarely consider network structures and textual topics together. In this paper, we propose a novel statistical model based on dynamic bayesian network, namely Multi-Topic Tracking Model for Dynamic Social Network (MTTD). It takes influence phenomenon, selection phenomenon, document generative process and the evolution of textual topics into account. Specifically, in our MTTD model, Gibbs Random Field is defined to model the influence of historical status of users in the network and the interdependency between them in order to consider the influence phenomenon. To address the selection phenomenon, a stochastic block model is used to model the link generation process based on the users' interests to topics. Probabilistic Latent Semantic Analysis (PLSA) is used to describe the document generative process according to the users' interests. Finally, the dependence on the historical topic status is also considered to ensure the continuity of the topic itself in topic evolution model. Expectation Maximization (EM) algorithm is utilized to estimate parameters in the proposed MTTD model. Empirical experiments on real datasets show that the MTTD model performs better than Popular Event Tracking (PET) and Dynamic Topic Model (DTM) in generalization performance, topic interpretability performance, topic content evolution and topic popularity evolution performance.

  19. Railway Track Allocation: Models and Methods

    DEFF Research Database (Denmark)

    Lusby, Richard Martin; Larsen, Jesper; Ehrgott, Matthias

    2011-01-01

    Efficiently coordinating the movement of trains on a railway network is a central part of the planning process for a railway company. This paper reviews models and methods that have been proposed in the literature to assist planners in finding train routes. Since the problem of routing trains on ...

  20. Railway Track Allocation: Models and Methods

    DEFF Research Database (Denmark)

    Lusby, Richard Martin; Larsen, Jesper; Ehrgott, Matthias

    Eciently coordinating the movement of trains on a railway network is a central part of the planning process for a railway company. This paper reviews models and methods that have been proposed in the literature to assist planners in nding train routes. Since the problem of routing trains on a rai...

  1. A study of V79 cell survival after for proton and carbon ion beams as represented by the parameters of Katz' track structure model

    DEFF Research Database (Denmark)

    Grzanka, Leszek; Waligórski, M. P. R.; Bassler, Niels

    Katz’s theory of cellular track structure (1) is an amorphous analytical model which applies a set of four cellular parameters representing survival of a given cell line after ion irradiation. Usually the values of these parameters are best fitted to a full set of experimentally measured survival...... carbon irradiation. 1. Katz, R., Track structure in radiobiology and in radiation detection. Nuclear Track Detection 2: 1-28 (1978). 2. Furusawa Y. et al. Inactivation of aerobic and hypoxic cells from three different cell lines by accelerated 3He-, 12C- and 20Ne beams. Radiat Res. 2012 Jan; 177...... curves available for a variety of ions. Once fitted, using these parameter values and the analytical formulae of the model calculations, cellular survival curves and RBE may be predicted for that cell line after irradiation by any ion, including mixed ion fields. While it is known that the Katz model...

  2. Comparison of Three Approximate Kinematic Models for Space Object Tracking

    Science.gov (United States)

    2013-07-01

    Object Tracking 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT...the filtering when the overall position error is above 400m . As more measurements are fused, the most accurate KPS model does achieve significantly

  3. Model tracking dual stochastic controller design under irregular internal noises

    International Nuclear Information System (INIS)

    Lee, Jong Bok; Heo, Hoon; Cho, Yun Hyun; Ji, Tae Young

    2006-01-01

    Although many methods about the control of irregular external noise have been introduced and implemented, it is still necessary to design a controller that will be more effective and efficient methods to exclude for various noises. Accumulation of errors due to model tracking, internal noises (thermal noise, shot noise and l/f noise) that come from elements such as resistor, diode and transistor etc. in the circuit system and numerical errors due to digital process often destabilize the system and reduce the system performance. New stochastic controller is adopted to remove those noises using conventional controller simultaneously. Design method of a model tracking dual controller is proposed to improve the stability of system while removing external and internal noises. In the study, design process of the model tracking dual stochastic controller is introduced that improves system performance and guarantees robustness under irregular internal noises which can be created internally. The model tracking dual stochastic controller utilizing F-P-K stochastic control technique developed earlier is implemented to reveal its performance via simulation

  4. Generalized Laplacian eigenmaps for modeling and tracking human motions.

    Science.gov (United States)

    Martinez-del-Rincon, Jesus; Lewandowski, Michal; Nebel, Jean-Christophe; Makris, Dimitrios

    2014-09-01

    This paper presents generalized Laplacian eigenmaps, a novel dimensionality reduction approach designed to address stylistic variations in time series. It generates compact and coherent continuous spaces whose geometry is data-driven. This paper also introduces graph-based particle filter, a novel methodology conceived for efficient tracking in low dimensional space derived from a spectral dimensionality reduction method. Its strengths are a propagation scheme, which facilitates the prediction in time and style, and a noise model coherent with the manifold, which prevents divergence, and increases robustness. Experiments show that a combination of both techniques achieves state-of-the-art performance for human pose tracking in underconstrained scenarios.

  5. High speed railway track dynamics models, algorithms and applications

    CERN Document Server

    Lei, Xiaoyan

    2017-01-01

    This book systematically summarizes the latest research findings on high-speed railway track dynamics, made by the author and his research team over the past decade. It explores cutting-edge issues concerning the basic theory of high-speed railways, covering the dynamic theories, models, algorithms and engineering applications of the high-speed train and track coupling system. Presenting original concepts, systematic theories and advanced algorithms, the book places great emphasis on the precision and completeness of its content. The chapters are interrelated yet largely self-contained, allowing readers to either read through the book as a whole or focus on specific topics. It also combines theories with practice to effectively introduce readers to the latest research findings and developments in high-speed railway track dynamics. It offers a valuable resource for researchers, postgraduates and engineers in the fields of civil engineering, transportation, highway & railway engineering.

  6. Computer models track atmospheric radionuclides worldwide

    International Nuclear Information System (INIS)

    Anon.

    1986-01-01

    The big sponge is what initiates call ARAC-the Atmospheric Release Advisory Capability-and it is vital to the clean-up after a nuclear accident. But this sobriquet doesn't refer to a propensity for mopping up radiation. It alludes to ARAC's ability to soak up data on weather conditions, regional geography, and the release of radionuclides into the atmosphere at thousands of sites around the globe. ARAC is a contingent of about 30 physicists, meteorologists, electronic engineers, computer scientists, and technicians who work at the Department of Energy's (DOE) Lawrence Livermore National Laboratory across the bay from San Francisco. The ARAC staff employs computer models to estimate the extent of surface contamination as well as radiation doses to population centers after hypothetical or real nuclear accidents. ARAC works fast. Within 15 minutes of an accident, it can produce a contour map estimating levels of radiation exposure within a 20-km radius of the accident site

  7. Advanced psychotherapy training: psychotherapy scholars' track, and the apprenticeship model.

    Science.gov (United States)

    Feinstein, Robert E; Yager, Joel

    2013-07-01

    Guided by ACGME's requirements, psychiatric residency training in psychotherapy currently focuses on teaching school-specific forms of psychotherapy (i.e., cognitive-behavioral, supportive, and psychodynamic psychotherapy). On the basis of a literature review of common factors affecting psychotherapy outcomes and experience with empirically supported and traditional psychotherapies, the authors aimed to develop an advanced contemporary and pragmatic approach to psychotherapy training for eight residents (two per PGY year) enrolled in a specialized Psychotherapy Scholars' Track within an adult general-residency program. The authors developed core principles and clinical practices, and drafted year-by-year educational goals and objectives to teach the psychotherapy scholars. Based on experiential learning principles, we also developed an individualized form of psychotherapy training, which we call "The Apprenticeship Model." The Psychotherapy Scholars' Track, and "Apprenticeship Model" of training are now in their third year. To date, authors report that scholars are highly satisfied with the structure and curriculum in the track. Trainees appreciate the protected time for self-directed study, mentored scholarship, and psychotherapy rotations. Patients and the Psychotherapy Scholars experience the "Apprenticeship Model" of psychotherapy training as authentic and compatible with their needs and resources. The Psychotherapy Scholars' Track developed and piloted in our general psychiatry residency is based on common factors, empirically-supported treatments, and use of experiential learning principles. Whether the Psychotherapy Scholars' Track and "Apprenticeship Model" will ultimately increase residents' psychotherapy skills and positively affect their ability to sustain postgraduate psychotherapy practice in varied settings requires long-term evaluation. The developers welcome empirical testing of the comparative effectiveness of this psychotherapy teaching approach

  8. Molecular dynamics study of amorphous pocket formation in Si at low energies and its application to improve binary collision models

    International Nuclear Information System (INIS)

    Santos, Ivan; Marques, Luis A.; Pelaz, Lourdes; Lopez, Pedro

    2007-01-01

    In this paper, we present classical molecular dynamics results about the formation of amorphous pockets in silicon for energy transfers below the displacement threshold. While in binary collision simulations ions with different masses generate the same number of Frenkel pairs for the same deposited nuclear energy, in molecular dynamics simulations the amount of damage and its complexity increase with ion mass. We demonstrate that low-energy transfers to target atoms are able to generate complex damage structures. We have determined the conditions that have to be fulfilled to produce amorphous pockets, showing that the order-disorder transition depends on the particular competition between melting and heat diffusion processes. We have incorporated these molecular dynamics results in an improved binary collision model that is able to provide a good description of damage with a very low computational cost

  9. Modeling the structure of amorphous MoS3: a neutron diffraction and reverse Monte Carlo study.

    Science.gov (United States)

    Hibble, Simon J; Wood, Glenn B

    2004-01-28

    A model for the structure of amorphous molybdenum trisulfide, a-MoS3, has been created using reverse Monte Carlo methods. This model, which consists of chains of MoS6 units sharing three sulfurs with each of its two neighbors and forming alternate long, nonbonded, and short, bonded, Mo-Mo separations, is a good fit to the neutron diffraction data and is chemically and physically realistic. The paper identifies the limitations of previous models based on Mo3 triangular clusters in accounting for the available experimental data.

  10. Reference-data modelling for tracking and tracing

    NARCIS (Netherlands)

    Dorp, van C.A.

    2004-01-01

    Subject headings: supply chain, tracking and tracing, reference-data modelling

  11. HCP track calculations in Lif:Mg,Ti: 3D modeling of the ''track – escape'' parameter

    International Nuclear Information System (INIS)

    Sattinger, D.; Sharon, A.; Horowitz, Y.S.

    2011-01-01

    The conceptual framework of the track interaction model (TIM) was conceived in the 1970s and mathematically formulated in the 1980s to describe heavy charged particle TL fluence response supralinearity. The extended track interaction model (ETIM) was developed to include saturation effects due to overlapping tracks and has been applied to both proton and alpha particle TL fluence response. One of the parameters of major importance in the TIM is the ''track – escape'' parameter, defined by N e /N w , where N e represents the number of electrons which escape the parent track during heating, and N w is the number of electrons which recombine within the parent track to produce a TL photon. Recently a first attempt was carried out to theoretically model escape parameters calculated in 2D geometry as a function of particle type and energy using trapping center (TC), luminescent center (LC) and competitive center (CC) occupation probabilities calculated from track segment radial dose distributions and optical absorption (OA) dose response. In this study, the calculations are extended to 3D geometry using a Monte Carlo approach which samples the point of creation of the charge carriers according to the TC occupation probabilities and then estimates N w by sampling the chord length to the track exterior. Charge carriers which escape the irradiated track volume contribute to N e . This more sophisticated 3D calculation of N e /N w is expected to increase the reliability of the modeling of heavy charged particle TL fluence response in the framework of the ETIM and enhance our understanding of “track effects” in Heavy Charged Particle (HCP) induced TL.

  12. Fundamentals of amorphous solids structure and properties

    CERN Document Server

    Stachurski, Zbigniew H

    2014-01-01

    Long awaited, this textbook fills the gap for convincing concepts to describe amorphous solids. Adopting a unique approach, the author develops a framework that lays the foundations for a theory of amorphousness. He unravels the scientific mysteries surrounding the topic, replacing rather vague notions of amorphous materials as disordered crystalline solids with the well-founded concept of ideal amorphous solids. A classification of amorphous materials into inorganic glasses, organic glasses, glassy metallic alloys, and thin films sets the scene for the development of the model of ideal amorph

  13. Modeling chemical and topological disorder in irradiation-amorphized silicon carbide

    International Nuclear Information System (INIS)

    Yuan Xianglong; Hobbs, Linn W.

    2002-01-01

    In order to explore the relationship of chemical disorder to topological disorder during irradiation-induced amorphization of silicon carbide, a topological analysis of homonuclear bond distribution, atom coordination number and network ring size distribution has been carried out for imposed simulated disorder, equilibrated with molecular dynamics (MD) procedures utilizing a Tersoff potential. Starting configurations included random atom positions, β-SiC coordinates chemically disordered over a range of chemical disorder parameters and atom coordinates generated from earlier MD simulations of embedded collision cascades. For random starting positions in embedded simulations, the MD refinement converged to an average Si coordination of 4.3 and an average of 1.4 Si-Si and 1.0 C-C bonds per Si and C site respectively. A chemical disorder threshold was observed (χ≡N C-C /N Si-C >0.3-0.4), below which range MD equilibration resulted in crystalline behavior at all temperatures and above which a glass transition was observed. It was thus concluded that amorphization is driven by a critical concentration of homonuclear bonds. About 80% of the density change at amorphization was attributable to threshold chemical disorder, while significant topological changes occurred only for larger values of the chemical disorder parameter

  14. Robust visual tracking of infrared object via sparse representation model

    Science.gov (United States)

    Ma, Junkai; Liu, Haibo; Chang, Zheng; Hui, Bin

    2014-11-01

    In this paper, we propose a robust tracking method for infrared object. We introduce the appearance model and the sparse representation in the framework of particle filter to achieve this goal. Representing every candidate image patch as a linear combination of bases in the subspace which is spanned by the target templates is the mechanism behind this method. The natural property, that if the candidate image patch is the target so the coefficient vector must be sparse, can ensure our algorithm successfully. Firstly, the target must be indicated manually in the first frame of the video, then construct the dictionary using the appearance model of the target templates. Secondly, the candidate image patches are selected in following frames and the sparse coefficient vectors of them are calculated via l1-norm minimization algorithm. According to the sparse coefficient vectors the right candidates is determined as the target. Finally, the target templates update dynamically to cope with appearance change in the tracking process. This paper also addresses the problem of scale changing and the rotation of the target occurring in tracking. Theoretic analysis and experimental results show that the proposed algorithm is effective and robust.

  15. Particle Tracking Model and Abstraction of Transport Processes

    International Nuclear Information System (INIS)

    Robinson, B.

    2000-01-01

    The purpose of the transport methodology and component analysis is to provide the numerical methods for simulating radionuclide transport and model setup for transport in the unsaturated zone (UZ) site-scale model. The particle-tracking method of simulating radionuclide transport is incorporated into the FEHM computer code and the resulting changes in the FEHM code are to be submitted to the software configuration management system. This Analysis and Model Report (AMR) outlines the assumptions, design, and testing of a model for calculating radionuclide transport in the unsaturated zone at Yucca Mountain. In addition, methods for determining colloid-facilitated transport parameters are outlined for use in the Total System Performance Assessment (TSPA) analyses. Concurrently, process-level flow model calculations are being carrier out in a PMR for the unsaturated zone. The computer code TOUGH2 is being used to generate three-dimensional, dual-permeability flow fields, that are supplied to the Performance Assessment group for subsequent transport simulations. These flow fields are converted to input files compatible with the FEHM code, which for this application simulates radionuclide transport using the particle-tracking algorithm outlined in this AMR. Therefore, this AMR establishes the numerical method and demonstrates the use of the model, but the specific breakthrough curves presented do not necessarily represent the behavior of the Yucca Mountain unsaturated zone

  16. Modeling self-occlusions in dynamic shape and appearance tracking

    KAUST Repository

    Yang, Yanchao

    2013-12-01

    We present a method to track the precise shape of a dynamic object in video. Joint dynamic shape and appearance models, in which a template of the object is propagated to match the object shape and radiance in the next frame, are advantageous over methods employing global image statistics in cases of complex object radiance and cluttered background. In cases of complex 3D object motion and relative viewpoint change, self-occlusions and disocclusions of the object are prominent, and current methods employing joint shape and appearance models are unable to accurately adapt to new shape and appearance information, leading to inaccurate shape detection. In this work, we model self-occlusions and dis-occlusions in a joint shape and appearance tracking framework. Experiments on video exhibiting occlusion/dis-occlusion, complex radiance and background show that occlusion/dis-occlusion modeling leads to superior shape accuracy compared to recent methods employing joint shape/appearance models or employing global statistics. © 2013 IEEE.

  17. Modelling and Simulations of a Narrow Track Tilting Vehicle

    Directory of Open Access Journals (Sweden)

    JJ Chong

    2016-10-01

    Full Text Available Narrow track tilting vehicle is a new category of vehicle that combines the dynamical abilities of a passenger car with a motorcycle. In the presence of overturning moments during cornering, an accurate assessment of the lateral dynamics plays an important role to improve their stability and handling. In order to stabilise or control the narrow tilting vehicle, the demand tilt angle can be calculated from the vehicle’s lateral acceleration and controlled by either steering input of the vehicle or using additional titling actuator to reach this desired angle. The aim of this article is to present a new approach for developing the lateral dynamics model of a narrow track tilting vehicle. First, this approach utilises the well-known geometry ‘bicycle model’ and parameter estimation methods. Second, by using a tuning method, the unknown and uncertainties are taken into account and regulated through an optimisation procedure to minimise the model biases in order to improve the modelling accuracy. Therefore, the optimised model can be used as a platform to develop the vehicle control strategy. Numerical simulations have been performed in a comparison with the experimental data to validate the model accuracy.

  18. Model tracking system for low-level radioactive waste disposal facilities: License application interrogatories and responses

    Energy Technology Data Exchange (ETDEWEB)

    Benbennick, M.E.; Broton, M.S.; Fuoto, J.S.; Novgrod, R.L.

    1994-08-01

    This report describes a model tracking system for a low-level radioactive waste (LLW) disposal facility license application. In particular, the model tracks interrogatories (questions, requests for information, comments) and responses. A set of requirements and desired features for the model tracking system was developed, including required structure and computer screens. Nine tracking systems were then reviewed against the model system requirements and only two were found to meet all requirements. Using Kepner-Tregoe decision analysis, a model tracking system was selected.

  19. Model tracking system for low-level radioactive waste disposal facilities: License application interrogatories and responses

    International Nuclear Information System (INIS)

    Benbennick, M.E.; Broton, M.S.; Fuoto, J.S.; Novgrod, R.L.

    1994-08-01

    This report describes a model tracking system for a low-level radioactive waste (LLW) disposal facility license application. In particular, the model tracks interrogatories (questions, requests for information, comments) and responses. A set of requirements and desired features for the model tracking system was developed, including required structure and computer screens. Nine tracking systems were then reviewed against the model system requirements and only two were found to meet all requirements. Using Kepner-Tregoe decision analysis, a model tracking system was selected

  20. A kinematic model for Bayesian tracking of cyclic human motion

    Science.gov (United States)

    Greif, Thomas; Lienhart, Rainer

    2010-01-01

    We introduce a two-dimensional kinematic model for cyclic motions of humans, which is suitable for the use as temporal prior in any Bayesian tracking framework. This human motion model is solely based on simple kinematic properties: the joint accelerations. Distributions of joint accelerations subject to the cycle progress are learned from training data. We present results obtained by applying the introduced model to the cyclic motion of backstroke swimming in a Kalman filter framework that represents the posterior distribution by a Gaussian. We experimentally evaluate the sensitivity of the motion model with respect to the frequency and noise level of assumed appearance-based pose measurements by simulating various fidelities of the pose measurements using ground truth data.

  1. Testing theoretical models of magnetic damping using an air track

    OpenAIRE

    Vidaurre, Ana; Riera, Jaime; Monsoriu, Juan A.; Gimenez, Marcos H.

    2007-01-01

    Magnetic braking is a long-established application of Lenz's law. A rigorous analysis of the laws governing this problem involves solving Maxwell's equations in a time-dependent situation. Approximate models have been developed to describe different experiences related to this phenomenon. In this paper we present a new method for the analysis of the magnetic braking using a magnet fixed to the glider of an air track. The forces acting on the glider, a result of the eddy currents, can be easil...

  2. 3-D model-based tracking for UAV indoor localization.

    Science.gov (United States)

    Teulière, Céline; Marchand, Eric; Eck, Laurent

    2015-05-01

    This paper proposes a novel model-based tracking approach for 3-D localization. One main difficulty of standard model-based approach lies in the presence of low-level ambiguities between different edges. In this paper, given a 3-D model of the edges of the environment, we derive a multiple hypotheses tracker which retrieves the potential poses of the camera from the observations in the image. We also show how these candidate poses can be integrated into a particle filtering framework to guide the particle set toward the peaks of the distribution. Motivated by the UAV indoor localization problem where GPS signal is not available, we validate the algorithm on real image sequences from UAV flights.

  3. Annealing Kinetic Model Using Fast and Slow Metastable Defects for Hydrogenated-Amorphous-Silicon-Based Solar Cells

    Directory of Open Access Journals (Sweden)

    Seung Yeop Myong

    2007-01-01

    Full Text Available The two-component kinetic model employing “fast” and “slow” metastable defects for the annealing behaviors in pin-type hydrogenated-amorphous-silicon- (a-Si:H- based solar cells is simulated using a normalized fill factor. Reported annealing data on pin-type a-Si:H-based solar cells are revisited and fitted using the model to confirm its validity. It is verified that the two-component model is suitable for fitting the various experimental phenomena. In addition, the activation energy for annealing of the solar cells depends on the definition of the recovery time. From the thermally activated and high electric field annealing behaviors, the plausible microscopic mechanism on the defect removal process is discussed.

  4. A new enhanced index tracking model in portfolio optimization with sum weighted approach

    Science.gov (United States)

    Siew, Lam Weng; Jaaman, Saiful Hafizah; Hoe, Lam Weng

    2017-04-01

    Index tracking is a portfolio management which aims to construct the optimal portfolio to achieve similar return with the benchmark index return at minimum tracking error without purchasing all the stocks that make up the index. Enhanced index tracking is an improved portfolio management which aims to generate higher portfolio return than the benchmark index return besides minimizing the tracking error. The objective of this paper is to propose a new enhanced index tracking model with sum weighted approach to improve the existing index tracking model for tracking the benchmark Technology Index in Malaysia. The optimal portfolio composition and performance of both models are determined and compared in terms of portfolio mean return, tracking error and information ratio. The results of this study show that the optimal portfolio of the proposed model is able to generate higher mean return than the benchmark index at minimum tracking error. Besides that, the proposed model is able to outperform the existing model in tracking the benchmark index. The significance of this study is to propose a new enhanced index tracking model with sum weighted apporach which contributes 67% improvement on the portfolio mean return as compared to the existing model.

  5. Modeling of amorphous SiCxO6/5 by classical molecular dynamics and first principles calculations

    Science.gov (United States)

    Liao, Ningbo; Zhang, Miao; Zhou, Hongming; Xue, Wei

    2017-02-01

    Polymer-derived silicon oxycarbide (SiCO) presents excellent performance for high temperature and lithium-ion battery applications. Current experiments have provided some information on nano-structure of SiCO, while it is very challenging for experiments to take further insight into the molecular structure and its relationship with properties of materials. In this work, molecular dynamics (MD) based on empirical potential and first principle calculation were combined to investigate amorphous SiCxO6/5 ceramics. The amorphous structures of SiCO containing silicon-centered mix bond tetrahedrons and free carbon were successfully reproduced. The calculated radial distribution, angular distribution and Young’s modulus were validated by current experimental data, and more details on molecular structure were discussed. The change in the slope of Young’s modulus is related to the glass transition temperature of the material. The proposed modeling approach can be used to predict the properties of SiCO with different compositions.

  6. Designing a Process for Tracking Business Model Change

    DEFF Research Database (Denmark)

    Groskovs, Sergejs

    that may alter the business model of the firm. The decision-making process about which metrics to track affects what management’s attention is focused on during the year. The rather streamlined process outlined here is capable of facilitating swift responses to environmental changes in local markets...... by establishing new KPIs on an ongoing basis together with the business units on the ground, and is thus of key importance to strategic management of the firm. The paper concludes with a discussion of its methodological compliance to design science research guidelines and revisits the literature in process......The paper has adopted a design science research approach to design and verify with key stakeholders a fundamental management process of revising KPIs (key performance indicators), including those indicators that are related to business model change. The paper proposes a general guide...

  7. Molecular modeling and simulation of atactic polystyrene/amorphous silica nanocomposites

    International Nuclear Information System (INIS)

    Mathioudakis, I; Vogiatzis, G G; Tzoumanekas, C; Theodorou, D N

    2016-01-01

    The local structure, segmental dynamics, topological analysis of entanglement networks and mechanical properties of atactic polystyrene - amorphous silica nanocomposites are studied via molecular simulations using two interconnected levels of representation: (a) A coarse - grained level. Equilibration at all length scales at this level is achieved via connectivity - altering Monte Carlo simulations. (b) An atomistic level. Initial configurations for atomistic Molecular Dynamics (MD) simulations are obtained by reverse mapping well- equilibrated coarse-grained configurations. By analyzing atomistic MD trajectories, the polymer density profile is found to exhibit layering in the vicinity of the nanoparticle surface. The dynamics of polystyrene (in neat and filled melt systems) is characterized in terms of bond orientation. Well-equilibrated coarse-grained long-chain configurations are reduced to entanglement networks via topological analysis with the CReTA algorithm. Atomistic simulation results for the mechanical properties are compared to the experimental measurements and other computational works. (paper)

  8. A drain current model for amorphous InGaZnO thin film transistors considering temperature effects

    Science.gov (United States)

    Cai, M. X.; Yao, R. H.

    2018-03-01

    Temperature dependent electrical characteristics of amorphous InGaZnO (a-IGZO) thin film transistors (TFTs) are investigated considering the percolation and multiple trapping and release (MTR) conduction mechanisms. Carrier-density and temperature dependent carrier mobility in a-IGZO is derived with the Boltzmann transport equation, which is affected by potential barriers above the conduction band edge with Gaussian-like distributions. The free and trapped charge densities in the channel are calculated with Fermi-Dirac statistics, and the field effective mobility of a-IGZO TFTs is then deduced based on the MTR theory. Temperature dependent drain current model for a-IGZO TFTs is finally derived with the obtained low field mobility and free charge density, which is applicable to both non-degenerate and degenerate conductions. This physical-based model is verified by available experiment results at various temperatures.

  9. Numerical simulation of hot-melt extrusion processes for amorphous solid dispersions using model-based melt viscosity.

    Science.gov (United States)

    Bochmann, Esther S; Steffens, Kristina E; Gryczke, Andreas; Wagner, Karl G

    2018-03-01

    Simulation of HME processes is a valuable tool for increased process understanding and ease of scale-up. However, the experimental determination of all required input parameters is tedious, namely the melt rheology of the amorphous solid dispersion (ASD) in question. Hence, a procedure to simplify the application of hot-melt extrusion (HME) simulation for forming amorphous solid dispersions (ASD) is presented. The commercial 1D simulation software Ludovic ® was used to conduct (i) simulations using a full experimental data set of all input variables including melt rheology and (ii) simulations using model-based melt viscosity data based on the ASDs glass transition and the physical properties of polymeric matrix only. Both types of HME computation were further compared to experimental HME results. Variation in physical properties (e.g. heat capacity, density) and several process characteristics of HME (residence time distribution, energy consumption) among the simulations and experiments were evaluated. The model-based melt viscosity was calculated by using the glass transition temperature (T g ) of the investigated blend and the melt viscosity of the polymeric matrix by means of a T g -viscosity correlation. The results of measured melt viscosity and model-based melt viscosity were similar with only few exceptions, leading to similar HME simulation outcomes. At the end, the experimental effort prior to HME simulation could be minimized and the procedure enables a good starting point for rational development of ASDs by means of HME. As model excipients, Vinylpyrrolidone-vinyl acetate copolymer (COP) in combination with various APIs (carbamazepine, dipyridamole, indomethacin, and ibuprofen) or polyethylene glycol (PEG 1500) as plasticizer were used to form the ASDs. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. The Quadrotor Dynamic Modeling and Indoor Target Tracking Control Method

    Directory of Open Access Journals (Sweden)

    Dewei Zhang

    2014-01-01

    Full Text Available A reliable nonlinear dynamic model of the quadrotor is presented. The nonlinear dynamic model includes actuator dynamic and aerodynamic effect. Since the rotors run near a constant hovering speed, the dynamic model is simplified at hovering operating point. Based on the simplified nonlinear dynamic model, the PID controllers with feedback linearization and feedforward control are proposed using the backstepping method. These controllers are used to control both the attitude and position of the quadrotor. A fully custom quadrotor is developed to verify the correctness of the dynamic model and control algorithms. The attitude of the quadrotor is measured by inertia measurement unit (IMU. The position of the quadrotor in a GPS-denied environment, especially indoor environment, is estimated from the downward camera and ultrasonic sensor measurements. The validity and effectiveness of the proposed dynamic model and control algorithms are demonstrated by experimental results. It is shown that the vehicle achieves robust vision-based hovering and moving target tracking control.

  11. Particle Tracking Model and Abstraction of Transport Processes

    International Nuclear Information System (INIS)

    Robinson, B.

    2004-01-01

    The purpose of this report is to document the abstraction model being used in total system performance assessment (TSPA) model calculations for radionuclide transport in the unsaturated zone (UZ). The UZ transport abstraction model uses the particle-tracking method that is incorporated into the finite element heat and mass model (FEHM) computer code (Zyvoloski et al. 1997 [DIRS 100615]) to simulate radionuclide transport in the UZ. This report outlines the assumptions, design, and testing of a model for calculating radionuclide transport in the UZ at Yucca Mountain. In addition, methods for determining and inputting transport parameters are outlined for use in the TSPA for license application (LA) analyses. Process-level transport model calculations are documented in another report for the UZ (BSC 2004 [DIRS 164500]). Three-dimensional, dual-permeability flow fields generated to characterize UZ flow (documented by BSC 2004 [DIRS 169861]; DTN: LB03023DSSCP9I.001 [DIRS 163044]) are converted to make them compatible with the FEHM code for use in this abstraction model. This report establishes the numerical method and demonstrates the use of the model that is intended to represent UZ transport in the TSPA-LA. Capability of the UZ barrier for retarding the transport is demonstrated in this report, and by the underlying process model (BSC 2004 [DIRS 164500]). The technical scope, content, and management of this report are described in the planning document ''Technical Work Plan for: Unsaturated Zone Transport Model Report Integration'' (BSC 2004 [DIRS 171282]). Deviations from the technical work plan (TWP) are noted within the text of this report, as appropriate. The latest version of this document is being prepared principally to correct parameter values found to be in error due to transcription errors, changes in source data that were not captured in the report, calculation errors, and errors in interpretation of source data

  12. Combined discriminative global and generative local models for visual tracking

    Science.gov (United States)

    Zhao, Liujun; Zhao, Qingjie; Chen, Yanming; Lv, Peng

    2016-03-01

    It is a challenging task to develop an effective visual tracking algorithm due to factors such as pose variation, rotation, and so on. Combined discriminative global and generative local appearance models are proposed to address this problem. Specifically, we develop a compact global object representation by extracting the low-frequency coefficients of the color and texture of the object based on two-dimensional discrete cosine transform. Then, with the global appearance representation, we learn a discriminative metric classifier in an online fashion to differentiate the target object from its background, which is very important to robustly indicate the changes in appearance. Second, we develop a new generative local model that exploits the scale invariant feature transform and its spatial geometric information. To make use of the advantages of the global discriminative model and the generative local model, we incorporate them into Bayesian inference framework. In this framework, the complementary models help the tracker locate the target more accurately. Furthermore, we use different mechanisms to update global and local templates to capture appearance changes. The experimental results demonstrate that the proposed approach performs favorably against state-of-the-art methods in terms of accuracy.

  13. Lattice preamorphization by ion irradiation: Fluence dependence of the electronic stopping power threshold for amorphization

    International Nuclear Information System (INIS)

    Agullo-Lopez, F.; Garcia, G.; Olivares, J.

    2005-01-01

    A thermal-spike model has been applied to characterize the damage structure of the latent tracks generated by high-energy ion irradiations on LiNbO 3 through electron excitation mechanisms. It applies to ions having electronic stopping powers both below and above the threshold value for lattice amorphization. The model allows to estimate the defect concentrations in the heavily damaged (preamorphized) regions that have not reached the threshold for amorphization. They include the halo and tail surrounding the core of a latent track. The existence of the preamorphized regions accounts for a synergy between successive irradiations and predicts a dependence of the amorphization threshold on previous irradiation fluence. The predicted dependence is in accordance with irradiation experiments using N (4.53 MeV), O (5.00 MeV), F (5.13 MeV), and Si (5 and 7.5 MeV). For electronic stopping powers above the threshold value the model describes the generation of homogeneous amorphous layers and predicts the propagation of the amorphization front with fluence. A theoretical expression, describing this propagation, has been obtained that is in reasonable agreement with silicon irradiation experiments at 5 and 7.5 MeV. The accordance is improved by including in a simple phenomenological way the velocity effect on the threshold. At the highest fluences (or depths) a significant discrepancy appears that may be attributed to the contribution of the nuclear collision damage

  14. Atomistic model of ultra-smooth amorphous thin film growth by low-energy ion-assisted physical vapour deposition

    International Nuclear Information System (INIS)

    Alvarez, R; Cotrino, J; Palmero, A; Vazquez, L; Gago, R; Redondo-Cubero, A

    2013-01-01

    The growth of ultra-smooth amorphous thin films induced by low-energy (below 1 keV) ion-assistance processes is studied. The relative contribution of ion-induced smoothening effects is analysed by means of a Monte Carlo model and experimental data. In general, highly rough granular or ultra-smooth (with roughness below one monolayer) films are produced depending on the competition between surface shadowing and ion-induced adatom mobility and sputtering. The ultra-smooth growth regime is experimentally and theoretically consistent with the Edwards–Wilkinson growth mode, which is related to the ion-induced enhancement of surface mobility. Overall, the framework and the fundamentals to analyse this type of growth are developed and discussed. (paper)

  15. Developing a particle tracking surrogate model to improve inversion of ground water - Surface water models

    Science.gov (United States)

    Cousquer, Yohann; Pryet, Alexandre; Atteia, Olivier; Ferré, Ty P. A.; Delbart, Célestine; Valois, Rémi; Dupuy, Alain

    2018-03-01

    The inverse problem of groundwater models is often ill-posed and model parameters are likely to be poorly constrained. Identifiability is improved if diverse data types are used for parameter estimation. However, some models, including detailed solute transport models, are further limited by prohibitive computation times. This often precludes the use of concentration data for parameter estimation, even if those data are available. In the case of surface water-groundwater (SW-GW) models, concentration data can provide SW-GW mixing ratios, which efficiently constrain the estimate of exchange flow, but are rarely used. We propose to reduce computational limits by simulating SW-GW exchange at a sink (well or drain) based on particle tracking under steady state flow conditions. Particle tracking is used to simulate advective transport. A comparison between the particle tracking surrogate model and an advective-dispersive model shows that dispersion can often be neglected when the mixing ratio is computed for a sink, allowing for use of the particle tracking surrogate model. The surrogate model was implemented to solve the inverse problem for a real SW-GW transport problem with heads and concentrations combined in a weighted hybrid objective function. The resulting inversion showed markedly reduced uncertainty in the transmissivity field compared to calibration on head data alone.

  16. Tracking people and cars using 3D modeling and CCTV.

    Science.gov (United States)

    Edelman, Gerda; Bijhold, Jurrien

    2010-10-10

    The aim of this study was to find a method for the reconstruction of movements of people and cars using CCTV footage and a 3D model of the environment. A procedure is proposed, in which video streams are synchronized and displayed in a 3D model, by using virtual cameras. People and cars are represented by cylinders and boxes, which are moved in the 3D model, according to their movements as shown in the video streams. The procedure was developed and tested in an experimental setup with test persons who logged their GPS coordinates as a recording of the ground truth. Results showed that it is possible to implement this procedure and to reconstruct movements of people and cars from video recordings. The procedure was also applied to a forensic case. In this work we experienced that more situational awareness was created by the 3D model, which made it easier to track people on multiple video streams. Based on all experiences from the experimental set up and the case, recommendations are formulated for use in practice. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

  17. Learning-based Nonlinear Model Predictive Control to Improve Vision-based Mobile Robot Path Tracking

    Science.gov (United States)

    2015-07-01

    Traditional path- tracking controllers would represent the robot using a bicycle model (Figure 8) with steering angle, δcmd,k, and linear velocity...Learning-based Nonlinear Model Predictive Control to Improve Vision-based Mobile Robot Path Tracking Chris J. Ostafew Institute for Aerospace Studies...paper presents a Learning-based Nonlinear Model Predictive Control (LB-NMPC) algorithm to achieve high-performance path tracking in challenging off-road

  18. Uranium fission track length distribution modelling for retracing chronothermometrical history of minerals

    International Nuclear Information System (INIS)

    Rebetez, M.

    1987-01-01

    Spontaneous fission of uranium 238 isotope contained in certain minerals creates damage zones called latent tracks, that can be etched chemically. The observation of these etched tracks and the measurement of their characteristics using an optical microscope are the basis of several applications in the domain of the earth sciences. First, the determination of their densities permits dating a mineral and establishing uranium mapping of rocks. Second, the measurement of their lengths can be a good source of information for retracing the thermal and tectonic history of the sample. The study of the partial annealing of tracks in apatite appears to be the ideal indicator for the evaluation of petroleum potential of a sedimentary basin. To allow the development of this application, it is necessary to devise a theoretical model of track length distributions. The model which is proposed takes into account the most realistic hypotheses concerning registration, etching and observation of tracks. The characteristics of surface tracks (projected lengths, depths, inclination angles, real lengths) and confined tracks (Track IN Track and Track IN Cleavage) are calculated. Surface tracks and confined tracks are perfectly complementary for chrono-thermometric interpretation of complex geological histories. The method is applied to the case of two samples with different tectonic history, issued from the cretaceous alcalin magmatism from the Pyrenees (Bilbao, Spain). A graphic method of distribution deconvolution is proposed. Finally, the uranium migration, depending on the hydrothermal alteration, is studied on the granite from Auriat (France) [fr

  19. Autonomous tracked robots in planar off-road conditions modelling, localization, and motion control

    CERN Document Server

    González, Ramón; Guzmán, José Luis

    2014-01-01

    This monograph is framed within the context of off-road mobile robotics. In particular, it discusses issues related to modelling, localization, and motion control of tracked mobile robots working in planar slippery conditions. Tracked locomotion constitutes a well-known solution for mobile platforms operating over diverse challenging terrains, for that reason, tracked robotics constitutes an important research field with many applications (e.g. agriculture, mining, search and rescue operations, military activities). The specific topics of this monograph are: historical perspective of tracked vehicles and tracked robots; trajectory-tracking model taking into account slip effect; visual-odometry-based localization strategies; and advanced slip-compensation motion controllers ensuring efficient real-time execution. Physical experiments with a real tracked robot are presented showing the better performance of the suggested novel approaches to known techniques.   Keywords: longitudinal slip, visual odometry, slip...

  20. Calculations of the magnetic entropy change in amorphous through a microscopic anisotropic model: Applications to Dy{sub 70}Zr{sub 30} and DyCo{sub 3.4} alloys

    Energy Technology Data Exchange (ETDEWEB)

    Ranke, P. J. von, E-mail: von.ranke@uol.com.br; Nóbrega, E. P.; Ribeiro, P. O.; Alvarenga, T. S. T.; Lopes, P. H. O.; Sousa, V. S. R. de; Oliveira, N. A. de [Instituto de Física, Universidade do Estado do Rio de Janeiro—UERJ, Rua São Francisco Xavier, 524, 20550-013 Rio de Janeiro (Brazil); Caldas, A. [Sociedade Unificada de Ensino Superior e Cultura, SUESC, 20211-351 Rio de Janeiro (Brazil); Alho, B. P. [Instituto de Aplicação Fernando Rodrigues da Silveira, Universidade do Estado do Rio de Janeiro, Rua Santa Alexandrina, 288, 20260-232 Rio de Janeiro (Brazil); Carvalho, G. [Laboratório Nacional de Luz Sincroton—LNLS, 13083-970 Campinas, São Paulo (Brazil); Magnus, A.

    2014-10-14

    We report theoretical investigations on the magnetocaloric effect, described by the magnetic entropy change in rare earth—transition metal amorphous systems. The model includes the local anisotropy on the rare earth ions in Harris-Plischke-Zuckermann assumptions. The transition metals ions are treated in terms of itinerant electron ferromagnetism and the magnetic moment of rare earth ions is coupled to the polarized d-band by a local exchange interaction. The magnetocaloric effect was calculated in DyCo{sub 3.4} system, which presents amorphous sperimagnetic configuration. The calculations predict higher refrigerant capacity in the amorphous DyCo{sub 3.4} than in DyCo{sub 2} crystal, highlighting the importance of amorphous magnetocaloric materials. Our calculation of the magnetocaloric effect in Dy{sub 70}Zr{sub 30}, which presents amorphous asperomagnetic configuration, is in good agreement with the experimental result. Furthermore, magnetic entropy changes associated with crystal-amorphous configurations change are estimated.

  1. Analytical drain current model for symmetric dual-gate amorphous indium gallium zinc oxide thin-film transistors

    Science.gov (United States)

    Qin, Ting; Liao, Congwei; Huang, Shengxiang; Yu, Tianbao; Deng, Lianwen

    2018-01-01

    An analytical drain current model based on the surface potential is proposed for amorphous indium gallium zinc oxide (a-InGaZnO) thin-film transistors (TFTs) with a synchronized symmetric dual-gate (DG) structure. Solving the electric field, surface potential (φS), and central potential (φ0) of the InGaZnO film using the Poisson equation with the Gaussian method and Lambert function is demonstrated in detail. The compact analytical model of current–voltage behavior, which consists of drift and diffusion components, is investigated by regional integration, and voltage-dependent effective mobility is taken into account. Comparison results demonstrate that the calculation results obtained using the derived models match well with the simulation results obtained using a technology computer-aided design (TCAD) tool. Furthermore, the proposed model is incorporated into SPICE simulations using Verilog-A to verify the feasibility of using DG InGaZnO TFTs for high-performance circuit designs.

  2. Simultaneous optical and electrical modeling of plasmonic light trapping in thin-film amorphous silicon photovoltaic devices

    Science.gov (United States)

    Gandhi, Keyur K.; Nejim, Ahmed; Beliatis, Michail J.; Mills, Christopher A.; Henley, Simon J.; Silva, S. Ravi P.

    2015-01-01

    Rapid prototyping of photovoltaic (PV) cells requires a method for the simultaneous simulation of the optical and electrical characteristics of the device. The development of nanomaterial-enabled PV cells only increases the complexity of such simulations. Here, we use a commercial technology computer aided design (TCAD) software, Silvaco Atlas, to design and model plasmonic gold nanoparticles integrated in optoelectronic device models of thin-film amorphous silicon (a-Si:H) PV cells. Upon illumination with incident light, we simulate the optical and electrical properties of the cell simultaneously and use the simulation to produce current-voltage (J-V) and external quantum efficiency plots. Light trapping due to light scattering and localized surface plasmon resonance interactions by the nanoparticles has resulted in the enhancement of both the optical and electrical properties due to the reduction in the recombination rates in the photoactive layer. We show that the device performance of the modeled plasmonic a-Si:H PV cells depends significantly on the position and size of the gold nanoparticles, which leads to improvements either in optical properties only, or in both optical and electrical properties. The model provides a route to optimize the device architecture by simultaneously optimizing the optical and electrical characteristics, which leads to a detailed understanding of plasmonic PV cells from a design perspective and offers an advanced tool for rapid device prototyping.

  3. A Coupled Hidden Markov Random Field Model for Simultaneous Face Clustering and Tracking in Videos

    KAUST Repository

    Wu, Baoyuan

    2016-10-25

    Face clustering and face tracking are two areas of active research in automatic facial video processing. They, however, have long been studied separately, despite the inherent link between them. In this paper, we propose to perform simultaneous face clustering and face tracking from real world videos. The motivation for the proposed research is that face clustering and face tracking can provide useful information and constraints to each other, thus can bootstrap and improve the performances of each other. To this end, we introduce a Coupled Hidden Markov Random Field (CHMRF) to simultaneously model face clustering, face tracking, and their interactions. We provide an effective algorithm based on constrained clustering and optimal tracking for the joint optimization of cluster labels and face tracking. We demonstrate significant improvements over state-of-the-art results in face clustering and tracking on several videos.

  4. Track-stitching using graphical models and message passing

    CSIR Research Space (South Africa)

    Van der Merwe, LJ

    2013-07-01

    Full Text Available state sequence (Viterbi path) using the pointer function, Pt. The probabilities can of course be implemented as costs (inverse probabilities), in this case the Viterbi algorithm aims to minimise the Viterbi cost. The track graph can now be solved... by maximising the association probability for the associations at each node, in each column of the track graph. This is akin to finding the most probable paths (lowest cost) through the track graph, where the paths are all mutually disjoint [10], i.e. the paths...

  5. Path Tracking Control of Automatic Parking Cloud Model considering the Influence of Time Delay

    Directory of Open Access Journals (Sweden)

    Yiding Hua

    2017-01-01

    Full Text Available This paper establishes the kinematic model of the automatic parking system and analyzes the kinematic constraints of the vehicle. Furthermore, it solves the problem where the traditional automatic parking system model fails to take into account the time delay. Firstly, based on simulating calculation, the influence of time delay on the dynamic trajectory of a vehicle in the automatic parking system is analyzed under the transverse distance Dlateral between different target spaces. Secondly, on the basis of cloud model, this paper utilizes the tracking control of an intelligent path closer to human intelligent behavior to further study the Cloud Generator-based parking path tracking control method and construct a vehicle path tracking control model. Moreover, tracking and steering control effects of the model are verified through simulation analysis. Finally, the effectiveness and timeliness of automatic parking controller in the aspect of path tracking are tested through a real vehicle experiment.

  6. Modelling of continuous and discontinuous floating slab tracks in a tunnel using a periodic approach

    Science.gov (United States)

    Gupta, S.; Degrande, G.

    2010-04-01

    This paper presents a periodic approach to couple a track and a tunnel-soil system of different periodicity. The periodicity of the track and the tunnel-soil system is exploited using the Floquet transform to efficiently formulate the problem in the frequency-wavenumber domain as well as to limit the discretization effort to a reference cell. The track and the tunnel-soil system are modelled as two separate systems of different periodicity and are coupled in the frequency-wavenumber domain. A coupled periodic finite element-boundary element method is used to model the tunnel-soil system, while a periodic finite element model or an analytical approach is used to model the track. A general analytical formulation to compute the response of three-dimensional periodic media that are excited by moving loads is discussed. It is shown that the response due to moving loads on the track can be calculated from the transfer function of the track-tunnel-soil system and the axle loads. A methodology for computing the transfer functions of the coupled track-tunnel-soil system as well as the computation of dynamic forces accounting for the interaction between the moving vehicle and the periodic track are described. The model accounts for quasi-static forces as well as dynamic forces due to parametric excitation and unevenness excitation. The methodology has been used to assess the vibration isolation efficiency of continuous and discontinuous floating slab tracks. It is concluded that both continuous and discontinuous floating slab tracks have a similar efficiency in the frequency range well above the isolation frequency of the slabs, which is usually higher than the slab passage frequency. In case of discontinuous slab tracks, the parametric excitation is found to be important, which results in a poorer performance of the track at low frequencies.

  7. The TL fluence response to heavy charged particles using the track interaction model and track structure information

    International Nuclear Information System (INIS)

    Rodriguez-Villafuerte, M.; Avila, O.

    2002-01-01

    The extended track interaction model, ETIM, has recently been proposed to explain the TLD-100 fluence response of peak 5 to heavy ions. This model includes the track structure information through the use of the luminescent-centre occupation probability obtained from radial dose distributions produced by the ions as they travel through the dosemeter. In this work an implementation of ETIM using Monte Carlo techniques is presented. The simulation was applied to calculate the response of peak 5 of both sensitised and normal TLD-100 crystals to 2.6 and 6.8 MeV 4 He ions. The simulation shows that the TL-fluence response has a strong dependence on ion energy, in disagreement with experimental observations. In spite of this, good agreement between the simulated TL-fluence response calculated for the 6.8 MeV 4 He radial distributions and the experimental data for the two energies was achieved. (author)

  8. Mathematical model to analyze the dissolution behavior of metastable crystals or amorphous drug accompanied with a solid-liquid interface reaction.

    Science.gov (United States)

    Hirai, Daiki; Iwao, Yasunori; Kimura, Shin-Ichiro; Noguchi, Shuji; Itai, Shigeru

    2017-04-30

    Metastable crystals and the amorphous state of poorly water-soluble drugs in solid dispersions (SDs), are subject to a solid-liquid interface reaction upon exposure to a solvent. The dissolution behavior during the solid-liquid interface reaction often shows that the concentration of drugs is supersaturated, with a high initial drug concentration compared with the solubility of stable crystals but finally approaching the latter solubility with time. However, a method for measuring the precipitation rate of stable crystals and/or the potential solubility of metastable crystals or amorphous drugs has not been established. In this study, a novel mathematical model that can represent the dissolution behavior of the solid-liquid interface reaction for metastable crystals or amorphous drug was developed and its validity was evaluated. The theory for this model was based on the Noyes-Whitney equation and assumes that the precipitation of stable crystals at the solid-liquid interface occurs through a first-order reaction. Moreover, two models were developed, one assuming that the surface area of the drug remains constant because of the presence of excess drug in the bulk and the other that the surface area changes in time-dependency because of agglomeration of the drug. SDs of Ibuprofen (IB)/polyvinylpyrrolidone (PVP) were prepared and their dissolution behaviors under non-sink conditions were fitted by the models to evaluate improvements in solubility. The model assuming time-dependent surface area showed good agreement with experimental values. Furthermore, by applying the model to the dissolution profile, parameters such as the precipitation rate and the potential solubility of the amorphous drug were successfully calculated. In addition, it was shown that the improvement in solubility with supersaturation was able to be evaluated quantitatively using this model. Therefore, this mathematical model would be a useful tool to quantitatively determine the supersaturation

  9. Stat-tracks and mediotypes: powerful tools for modern ichnology based on 3D models

    Directory of Open Access Journals (Sweden)

    Matteo Belvedere

    2018-01-01

    Full Text Available Vertebrate tracks are subject to a wide distribution of morphological types. A single trackmaker may be associated with a range of tracks reflecting individual pedal anatomy and behavioural kinematics mediated through substrate properties which may vary both in space and time. Accordingly, the same trackmaker can leave substantially different morphotypes something which must be considered in creating ichnotaxa. In modern practice this is often captured by the collection of a series of 3D track models. We introduce two concepts to help integrate these 3D models into ichnological analysis procedures. The mediotype is based on the idea of using statistically-generated three-dimensional track models (median or mean of the type specimens to create a composite track to support formal recognition of a ichno type. A representative track (mean and/or median is created from a set of individual reference tracks or from multiple examples from one or more trackways. In contrast, stat-tracks refer to other digitally generated tracks which may explore variance. For example, they are useful in: understanding the preservation variability of a given track sample; identifying characteristics or unusual track features; or simply as a quantitative comparison tool. Both concepts assist in making ichnotaxonomical interpretations and we argue that they should become part of the standard procedure when instituting new ichnotaxa. As three-dimensional models start to become a standard in publications on vertebrate ichnology, the mediotype and stat-track concepts have the potential to help guiding a revolution in the study of vertebrate ichnology and ichnotaxonomy.

  10. CELL TRACKING USING PARTICLE FILTERS WITH IMPLICIT CONVEX SHAPE MODEL IN 4D CONFOCAL MICROSCOPY IMAGES.

    Science.gov (United States)

    Ramesh, Nisha; Tasdizen, Tolga

    2014-10-01

    Bayesian frameworks are commonly used in tracking algorithms. An important example is the particle filter, where a stochastic motion model describes the evolution of the state, and the observation model relates the noisy measurements to the state. Particle filters have been used to track the lineage of cells. Propagating the shape model of the cell through the particle filter is beneficial for tracking. We approximate arbitrary shapes of cells with a novel implicit convex function. The importance sampling step of the particle filter is defined using the cost associated with fitting our implicit convex shape model to the observations. Our technique is capable of tracking the lineage of cells for nonmitotic stages. We validate our algorithm by tracking the lineage of retinal and lens cells in zebrafish embryos.

  11. Particle Tracking and Deposition from CFD Simulations using a Viscoelastic Particle Model

    NARCIS (Netherlands)

    Losurdo, M.

    2009-01-01

    In the present dissertation the mathematical modelling of particle deposition is studied and the solution algorithms for particle tracking, deposition and deposit growth are developed. Particle deposition is modelled according to mechanical impact and contact mechanics taking into account the

  12. Modeling of Maximum Power Point Tracking Controller for Solar Power System

    Directory of Open Access Journals (Sweden)

    Aryuanto Soetedjo

    2012-09-01

    Full Text Available In this paper, a Maximum Power Point Tracking (MPPT controller for solar power system is modeled using MATLAB Simulink. The model consists of PV module, buck converter, and MPPT controller. The contribution of the work is in the modeling of buck converter that allowing the input voltage of the converter, i.e. output voltage of PV is changed by varying the duty cycle, so that the maximum power point could be tracked when the environmental changes. The simulation results show that the developed model performs well in tracking the maximum power point (MPP of the PV module using Perturb and Observe (P&O Algorithm.

  13. Modeling track access charge to enhance railway industry performance

    Science.gov (United States)

    Berawi, Mohammed Ali; Miraj, Perdana; Berawi, Abdur Rohim Boy; Susantono, Bambang; Leviakangas, Pekka; Radiansyah, Hendra

    2017-11-01

    Indonesia attempts to improve nation's competitiveness by increasing the quality and the availability of railway network. However, the infrastructure improperly managed by the operator in terms of the technical issue. One of the reasons for this problem is an unbalanced value of infrastructure charge. In 2000's track access charge and infrastructure maintenance and operation for Indonesia railways are equal and despite current formula of the infrastructure charge, issues of transparency and accountability still in question. This research aims to produce an alternative scheme of track access charge by considering marginal cost plus markup (MC+) approach. The research combines qualitative and quantitative method through an in-depth interview and financial analysis. The result will generate alternative formula of infrastructure charge in Indonesia's railway industry. The simulation also conducted to estimate track access charge for the operator and to forecast government support in terms of subsidy. The result is expected to enhance railway industry performance and competitiveness.

  14. A numerical model for the thermal history of rocks based on confined horizontal fission tracks

    International Nuclear Information System (INIS)

    Jensen, P.K.; Kunzendorf, Helmar; Hansen, Kirsten

    1992-01-01

    A numerical model for determination of the thermal history of rocks is presented. It is shown that the thermal history may be uniquely determined as a piece-by-piece linear function on the basis of etched confined, horizontal fission track length distributions, their surface densities, and the uranium content. The initial track length distribution is taken into account. A relation between the measured track length distribution and age is given which includes correction for partial annealing. The annealing model used is the fanning Arrhenius plot. It is shown that track length distributions measured in transmitted light are biased favouring short tracks compared with measurements in reflected light. Testing of the model is performed on apatites from a tuffaceous sandstone from Bornholm (Denmark) yielding an estimate of the thermal history for the period of about 280 Ma back in time. (author)

  15. Momentum analysis by using a quintic spline model for the track

    CERN Document Server

    Wind, H

    1974-01-01

    A method is described to determine the momentum of a particle when the (inhomogeneous) analysing magnetic field and the position of at least three points on the track are known. The model of the field is essentially a cubic spline and that of the track a quintic spline. (8 refs).

  16. A Cost-Effective Tracking Algorithm for Hypersonic Glide Vehicle Maneuver Based on Modified Aerodynamic Model

    Directory of Open Access Journals (Sweden)

    Yu Fan

    2016-10-01

    Full Text Available In order to defend the hypersonic glide vehicle (HGV, a cost-effective single-model tracking algorithm using Cubature Kalman filter (CKF is proposed in this paper based on modified aerodynamic model (MAM as process equation and radar measurement model as measurement equation. In the existing aerodynamic model, the two control variables attack angle and bank angle cannot be measured by the existing radar equipment and their control laws cannot be known by defenders. To establish the process equation, the MAM for HGV tracking is proposed by using additive white noise to model the rates of change of the two control variables. For the ease of comparison several multiple model algorithms based on CKF are presented, including interacting multiple model (IMM algorithm, adaptive grid interacting multiple model (AGIMM algorithm and hybrid grid multiple model (HGMM algorithm. The performances of these algorithms are compared and analyzed according to the simulation results. The simulation results indicate that the proposed tracking algorithm based on modified aerodynamic model has the best tracking performance with the best accuracy and least computational cost among all tracking algorithms in this paper. The proposed algorithm is cost-effective for HGV tracking.

  17. Physical Models for Particle Tracking Simulations in the RF Gap

    Energy Technology Data Exchange (ETDEWEB)

    Shishlo, Andrei P. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Holmes, Jeffrey A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-06-01

    This document describes the algorithms that are used in the PyORBIT code to track the particles accelerated in the Radio-Frequency cavities. It gives the mathematical description of the algorithms and the assumptions made in each case. The derived formulas have been implemented in the PyORBIT code. The necessary data for each algorithm are described in detail.

  18. TO THE MODELING ISSUES OF LIFE CYCLE OF DEFORMATION WORK OF THE RAILWAY TRACK ELEMENTS

    Directory of Open Access Journals (Sweden)

    I. O. Bondarenko

    2014-12-01

    Full Text Available Purpose. This article highlightsthe operational cycle modeling of the railway track elements for the development processes study of deformability as the basis of creating a regulatory framework of the track while ensuring the reliability of the railways. Methodology.The basic theory of wave propagation process in describing the interaction of track and rolling stock are used to achieve the goal. Findings. The basic provisions concerning the concept «the operational cycle of the deformation track» were proposed and formulated. The method was set. On its base the algorithm for determining the dynamic effects of the rolling stock on the way was obtained. The basic principles for the calculation schemes of railway track components for process evaluation of the deformability of the way were formulated. An algorithm was developed, which allows getting the field values of stresses, strains and displacements of all points of the track design elements. Based on the fields of stress-strain state of the track, an algorithm to establish the dependence of the process of deformability and the amount of energy expended on the deformability of the track operation was created. Originality.The research of track reliability motivates the development of new models, provides an opportunity to consider it for some developments. There is a need to define the criteria on which the possibility of assessing and forecasting changes in the track states in the course of its operation. The paper proposed the basic principles, methods, algorithms, and the terms relating to the conduct of the study, questions the reliability of the track. Practical value. Analytical models, used to determine the parameters of strength and stability of tracks, fully meet its objectives, but cannot be applied to determine the parameters of track reliability. One of the main factors of impossibility to apply these models is a quasi-dynamic approach. Therefore, as a rule, not only one dynamic

  19. A novel vehicle tracking algorithm based on mean shift and active contour model in complex environment

    Science.gov (United States)

    Cai, Lei; Wang, Lin; Li, Bo; Zhang, Libao; Lv, Wen

    2017-06-01

    Vehicle tracking technology is currently one of the most active research topics in machine vision. It is an important part of intelligent transportation system. However, in theory and technology, it still faces many challenges including real-time and robustness. In video surveillance, the targets need to be detected in real-time and to be calculated accurate position for judging the motives. The contents of video sequence images and the target motion are complex, so the objects can't be expressed by a unified mathematical model. Object-tracking is defined as locating the interest moving target in each frame of a piece of video. The current tracking technology can achieve reliable results in simple environment over the target with easy identified characteristics. However, in more complex environment, it is easy to lose the target because of the mismatch between the target appearance and its dynamic model. Moreover, the target usually has a complex shape, but the tradition target tracking algorithm usually represents the tracking results by simple geometric such as rectangle or circle, so it cannot provide accurate information for the subsequent upper application. This paper combines a traditional object-tracking technology, Mean-Shift algorithm, with a kind of image segmentation algorithm, Active-Contour model, to get the outlines of objects while the tracking process and automatically handle topology changes. Meanwhile, the outline information is used to aid tracking algorithm to improve it.

  20. The probabilities of one- and multi-track events for modeling radiation-induced cell kill

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, Uwe; Vasi, Fabiano; Besserer, Juergen [University of Zuerich, Department of Physics, Science Faculty, Zurich (Switzerland); Radiotherapy Hirslanden, Zurich (Switzerland)

    2017-08-15

    In view of the clinical importance of hypofractionated radiotherapy, track models which are based on multi-hit events are currently reinvestigated. These models are often criticized, because it is believed that the probability of multi-track hits is negligible. In this work, the probabilities for one- and multi-track events are determined for different biological targets. The obtained probabilities can be used with nano-dosimetric cluster size distributions to obtain the parameters of track models. We quantitatively determined the probabilities for one- and multi-track events for 100, 500 and 1000 keV electrons, respectively. It is assumed that the single tracks are statistically independent and follow a Poisson distribution. Three different biological targets were investigated: (1) a DNA strand (2 nm scale); (2) two adjacent chromatin fibers (60 nm); and (3) fiber loops (300 nm). It was shown that the probabilities for one- and multi-track events are increasing with energy, size of the sensitive target structure, and dose. For a 2 x 2 x 2 nm{sup 3} target, one-track events are around 10,000 times more frequent than multi-track events. If the size of the sensitive structure is increased to 100-300 nm, the probabilities for one- and multi-track events are of the same order of magnitude. It was shown that target theories can play a role for describing radiation-induced cell death if the targets are of the size of two adjacent chromatin fibers or fiber loops. The obtained probabilities can be used together with the nano-dosimetric cluster size distributions to determine model parameters for target theories. (orig.)

  1. Analytical theory of noncollinear amorphous metallic magnetism

    International Nuclear Information System (INIS)

    Kakehashi, Y.; Uchida, T.

    2001-01-01

    Analytical theory of noncollinear magnetism in amorphous metals is proposed on the basis of the Gaussian model for the distribution of the interatomic distance and the saddle-point approximation. The theory removes the numerical difficulty in the previous theory based on the Monte-Carlo sampling method, and reasonably describes the magnetic properties of amorphous transition metals

  2. A Model of the Effects of Acceleration on a Pursuit Tracking Task

    National Research Council Canada - National Science Library

    McKinley, Richard A; Fullerton, Kathy L; Tripp, Jr., Lloyd D; Esken, Robert L; Goodyear, Chuck

    2004-01-01

    .... A mathematical model of this task could become useful when planning air combat missions. Eight subjects performed a 2-D manual pursuit tracking task during four different Gz conditions in a human centrifuge simulator...

  3. Swift heavy ion-beam induced amorphization and recrystallization of yttrium iron garnet.

    Science.gov (United States)

    Costantini, Jean-Marc; Miro, Sandrine; Beuneu, François; Toulemonde, Marcel

    2015-12-16

    Pure and (Ca and Si)-substituted yttrium iron garnet (Y3Fe5O12 or YIG) epitaxial layers and amorphous films on gadolinium gallium garnet (Gd3Ga5O12, or GGG) single crystal substrates were irradiated by 50 MeV (32)Si and 50 MeV (or 60 MeV) (63)Cu ions for electronic stopping powers larger than the threshold value (~4 MeV μm(-1)) for amorphous track formation in YIG crystals. Conductivity data of crystalline samples in a broad ion fluence range (10(11)-10(16) cm(-2)) are modeled with a set of rate equations corresponding to the amorphization and recrystallization induced in ion tracks by electronic excitations. The data for amorphous layers confirm that a recrystallization process takes place above ~10(14) cm(-2). Cross sections for both processes deduced from this analysis are discussed in comparison to previous determinations with reference to the inelastic thermal-spike model of track formation. Micro-Raman spectroscopy was also used to follow the related structural modifications. Raman spectra show the progressive vanishing and randomization of crystal phonon modes in relation to the ion-induced damage. For crystalline samples irradiated at high fluences (⩾10(14) cm(-2)), only two prominent broad bands remain like for amorphous films, thereby reflecting the phonon density of states of the disordered solid, regardless of samples and irradiation conditions. The main band peaked at ~660 cm(-1) is assigned to vibration modes of randomized bonds in tetrahedral (FeO4) units.

  4. Trajectory Tracking and Stabilization of a Quadrotor Using Model Predictive Control of Laguerre Functions

    Directory of Open Access Journals (Sweden)

    Mapopa Chipofya

    2015-01-01

    Full Text Available This paper presents a solution to stability and trajectory tracking of a quadrotor system using a model predictive controller designed using a type of orthonormal functions called Laguerre functions. A linear model of the quadrotor is derived and used. To check the performance of the controller we compare it with a linear quadratic regulator and a more traditional linear state space MPC. Simulations for trajectory tracking and stability are performed in MATLAB and results provided in this paper.

  5. ADAPTIVE BACKGROUND DENGAN METODE GAUSSIAN MIXTURE MODELS UNTUK REAL-TIME TRACKING

    Directory of Open Access Journals (Sweden)

    Silvia Rostianingsih

    2008-01-01

    Full Text Available Nowadays, motion tracking application is widely used for many purposes, such as detecting traffic jam and counting how many people enter a supermarket or a mall. A method to separate background and the tracked object is required for motion tracking. It will not be hard to develop the application if the tracking is performed on a static background, but it will be difficult if the tracked object is at a place with a non-static background, because the changing part of the background can be recognized as a tracking area. In order to handle the problem an application can be made to separate background where that separation can adapt to change that occur. This application is made to produce adaptive background using Gaussian Mixture Models (GMM as its method. GMM method clustered the input pixel data with pixel color value as it’s basic. After the cluster formed, dominant distributions are choosen as background distributions. This application is made by using Microsoft Visual C 6.0. The result of this research shows that GMM algorithm could made adaptive background satisfactory. This proofed by the result of the tests that succeed at all condition given. This application can be developed so the tracking process integrated in adaptive background maker process. Abstract in Bahasa Indonesia : Saat ini, aplikasi motion tracking digunakan secara luas untuk banyak tujuan, seperti mendeteksi kemacetan dan menghitung berapa banyak orang yang masuk ke sebuah supermarket atau sebuah mall. Sebuah metode untuk memisahkan antara background dan obyek yang di-track dibutuhkan untuk melakukan motion tracking. Membuat aplikasi tracking pada background yang statis bukanlah hal yang sulit, namun apabila tracking dilakukan pada background yang tidak statis akan lebih sulit, dikarenakan perubahan background dapat dikenali sebagai area tracking. Untuk mengatasi masalah tersebut, dapat dibuat suatu aplikasi untuk memisahkan background dimana aplikasi tersebut dapat

  6. Non-Rigid Object Contour Tracking via a Novel Supervised Level Set Model.

    Science.gov (United States)

    Sun, Xin; Yao, Hongxun; Zhang, Shengping; Li, Dong

    2015-11-01

    We present a novel approach to non-rigid objects contour tracking in this paper based on a supervised level set model (SLSM). In contrast to most existing trackers that use bounding box to specify the tracked target, the proposed method extracts the accurate contours of the target as tracking output, which achieves better description of the non-rigid objects while reduces background pollution to the target model. Moreover, conventional level set models only emphasize the regional intensity consistency and consider no priors. Differently, the curve evolution of the proposed SLSM is object-oriented and supervised by the specific knowledge of the targets we want to track. Therefore, the SLSM can ensure a more accurate convergence to the exact targets in tracking applications. In particular, we firstly construct the appearance model for the target in an online boosting manner due to its strong discriminative power between the object and the background. Then, the learnt target model is incorporated to model the probabilities of the level set contour by a Bayesian manner, leading the curve converge to the candidate region with maximum likelihood of being the target. Finally, the accurate target region qualifies the samples fed to the boosting procedure as well as the target model prepared for the next time step. We firstly describe the proposed mechanism of two-phase SLSM for single target tracking, then give its generalized multi-phase version for dealing with multi-target tracking cases. Positive decrease rate is used to adjust the learning pace over time, enabling tracking to continue under partial and total occlusion. Experimental results on a number of challenging sequences validate the effectiveness of the proposed method.

  7. Model-Based Localization and Tracking Using Bluetooth Low-Energy Beacons

    Directory of Open Access Journals (Sweden)

    F. Serhan Daniş

    2017-10-01

    Full Text Available We introduce a high precision localization and tracking method that makes use of cheap Bluetooth low-energy (BLE beacons only. We track the position of a moving sensor by integrating highly unreliable and noisy BLE observations streaming from multiple locations. A novel aspect of our approach is the development of an observation model, specifically tailored for received signal strength indicator (RSSI fingerprints: a combination based on the optimal transport model of Wasserstein distance. The tracking results of the entire system are compared with alternative baseline estimation methods, such as nearest neighboring fingerprints and an artificial neural network. Our results show that highly accurate estimation from noisy Bluetooth data is practically feasible with an observation model based on Wasserstein distance interpolation combined with the sequential Monte Carlo (SMC method for tracking.

  8. Model-Based Localization and Tracking Using Bluetooth Low-Energy Beacons.

    Science.gov (United States)

    Daniş, F Serhan; Cemgil, Ali Taylan

    2017-10-29

    We introduce a high precision localization and tracking method that makes use of cheap Bluetooth low-energy (BLE) beacons only. We track the position of a moving sensor by integrating highly unreliable and noisy BLE observations streaming from multiple locations. A novel aspect of our approach is the development of an observation model, specifically tailored for received signal strength indicator (RSSI) fingerprints: a combination based on the optimal transport model of Wasserstein distance. The tracking results of the entire system are compared with alternative baseline estimation methods, such as nearest neighboring fingerprints and an artificial neural network. Our results show that highly accurate estimation from noisy Bluetooth data is practically feasible with an observation model based on Wasserstein distance interpolation combined with the sequential Monte Carlo (SMC) method for tracking.

  9. Basic simulation models of phase tracking devices using Matlab

    CERN Document Server

    Tranter, William

    2010-01-01

    The Phase-Locked Loop (PLL), and many of the devices used for frequency and phase tracking, carrier and symbol synchronization, demodulation, and frequency synthesis, are fundamental building blocks in today's complex communications systems. It is therefore essential for both students and practicing communications engineers interested in the design and implementation of modern communication systems to understand and have insight into the behavior of these important and ubiquitous devices. Since the PLL behaves as a nonlinear device (at least during acquisition), computer simulation can be used

  10. MULTIPLE HUMAN TRACKING IN COMPLEX SITUATION BY DATA ASSIMILATION WITH PEDESTRIAN BEHAVIOR MODEL

    Directory of Open Access Journals (Sweden)

    W. Nakanishi

    2012-07-01

    Full Text Available A new method of multiple human tracking is proposed. The key concept is that to assume a tracking process as a data assimilation process. Despite the importance of understanding pedestrian behavior in public space with regard to achieving more sophisticated space design and flow control, automatic human tracking in complex situation is still challenging when people move close to each other or are occluded by others. For this difficulty, we stochastically combine existing tracking method by image processing with simulation models of walking behavior. We describe a system in a form of general state space model and define the components of the model according to the review on related works. Then we apply the proposed method to the data acquired at the ticket gate of the railway station. We show the high performance of the method, as well as compare the result with other model to present the advantage of integrating the behavior model to the tracking method. We also show the method's ability to acquire passenger flow information such as ticket gate choice and OD data automatically from the tracking result.

  11. A fast fiducial marker tracking model for fully automatic alignment in electron tomography

    KAUST Repository

    Han, Renmin

    2017-10-20

    Automatic alignment, especially fiducial marker-based alignment, has become increasingly important due to the high demand of subtomogram averaging and the rapid development of large-field electron microscopy. Among the alignment steps, fiducial marker tracking is a crucial one that determines the quality of the final alignment. Yet, it is still a challenging problem to track the fiducial markers accurately and effectively in a fully automatic manner.In this paper, we propose a robust and efficient scheme for fiducial marker tracking. Firstly, we theoretically prove the upper bound of the transformation deviation of aligning the positions of fiducial markers on two micrographs by affine transformation. Secondly, we design an automatic algorithm based on the Gaussian mixture model to accelerate the procedure of fiducial marker tracking. Thirdly, we propose a divide-and-conquer strategy against lens distortions to ensure the reliability of our scheme. To our knowledge, this is the first attempt that theoretically relates the projection model with the tracking model. The real-world experimental results further support our theoretical bound and demonstrate the effectiveness of our algorithm. This work facilitates the fully automatic tracking for datasets with a massive number of fiducial markers.The C/C ++ source code that implements the fast fiducial marker tracking is available at https://github.com/icthrm/gmm-marker-tracking. Markerauto 1.6 version or later (also integrated in the AuTom platform at http://ear.ict.ac.cn/) offers a complete implementation for fast alignment, in which fast fiducial marker tracking is available by the

  12. A fast fiducial marker tracking model for fully automatic alignment in electron tomography.

    Science.gov (United States)

    Han, Renmin; Zhang, Fa; Gao, Xin

    2018-03-01

    Automatic alignment, especially fiducial marker-based alignment, has become increasingly important due to the high demand of subtomogram averaging and the rapid development of large-field electron microscopy. Among the alignment steps, fiducial marker tracking is a crucial one that determines the quality of the final alignment. Yet, it is still a challenging problem to track the fiducial markers accurately and effectively in a fully automatic manner. In this paper, we propose a robust and efficient scheme for fiducial marker tracking. Firstly, we theoretically prove the upper bound of the transformation deviation of aligning the positions of fiducial markers on two micrographs by affine transformation. Secondly, we design an automatic algorithm based on the Gaussian mixture model to accelerate the procedure of fiducial marker tracking. Thirdly, we propose a divide-and-conquer strategy against lens distortions to ensure the reliability of our scheme. To our knowledge, this is the first attempt that theoretically relates the projection model with the tracking model. The real-world experimental results further support our theoretical bound and demonstrate the effectiveness of our algorithm. This work facilitates the fully automatic tracking for datasets with a massive number of fiducial markers. The C/C ++ source code that implements the fast fiducial marker tracking is available at https://github.com/icthrm/gmm-marker-tracking. Markerauto 1.6 version or later (also integrated in the AuTom platform at http://ear.ict.ac.cn/) offers a complete implementation for fast alignment, in which fast fiducial marker tracking is available by the '-t' option. xin.gao@kaust.edu.sa. Supplementary data are available at Bioinformatics online. © The Author(s) 2017. Published by Oxford University Press.

  13. Room temperature photoluminescence spectrum modeling of hydrogenated amorphous silicon carbide thin films by a joint density of tail states approach and its application to plasma deposited hydrogenated amorphous silicon carbide thin films

    International Nuclear Information System (INIS)

    Sel, Kıvanç; Güneş, İbrahim

    2012-01-01

    Room temperature photoluminescence (PL) spectrum of hydrogenated amorphous silicon carbide (a-SiC x :H) thin films was modeled by a joint density of tail states approach. In the frame of these analyses, the density of tail states was defined in terms of empirical Gaussian functions for conduction and valance bands. The PL spectrum was represented in terms of an integral of joint density of states functions and Fermi distribution function. The analyses were performed for various values of energy band gap, Fermi energy and disorder parameter, which is a parameter that represents the width of the energy band tails. Finally, the model was applied to the measured room temperature PL spectra of a-SiC x :H thin films deposited by plasma enhanced chemical vapor deposition system, with various carbon contents, which were determined by X-ray photoelectron spectroscopy measurements. The energy band gap and disorder parameters of the conduction and valance band tails were determined and compared with the optical energies and Urbach energies, obtained by UV–Visible transmittance measurements. As a result of the analyses, it was observed that the proposed model sufficiently represents the room temperature PL spectra of a-SiC x :H thin films. - Highlights: ► Photoluminescence spectra (PL) of the films were modeled. ► In the model, joint density of tail states and Fermi distribution function are used. ► Various values of energy band gap, Fermi energy and disorder parameter are applied. ► The model was applied to the measured PL of the films. ► The proposed model represented the room temperature PL spectrum of the films.

  14. On track for success: an innovative behavioral science curriculum model.

    Science.gov (United States)

    Freedy, John R; Carek, Peter J; Dickerson, Lori M; Mallin, Robert M

    2013-01-01

    This article describes the behavioral science curriculum currently in place at the Trident/MUSC Family Medicine Residency Program. The Trident/MUSC Program is a 10-10-10 community-based, university-affiliated program in Charleston, South Carolina. Over the years, the Trident/MUSC residency program has graduated over 400 Family Medicine physicians. The current behavioral science curriculum consists of both required core elements (didactic lectures, clinical observation, Balint groups, and Resident Grand Rounds) as well as optional elements (longitudinal patient care experiences, elective rotations, behavioral science editorial experience, and scholars project with a behavioral science focus). All Trident/MUSC residents complete core behavioral science curriculum elements and are free to participate in none, some, or all of the optional behavioral science curriculum elements. This flexibility allows resident physicians to tailor the educational program in a manner to meet individual educational needs. The behavioral science curriculum is based upon faculty interpretation of existing "best practice" guidelines (Residency Review Committee-Family Medicine and AAFP). This article provides sufficient curriculum detail to allow the interested reader the opportunity to adapt elements of the behavioral science curriculum to other residency training programs. While this behavioral science track system is currently in an early stage of implementation, the article discusses track advantages as well as future plans to evaluate various aspects of this innovative educational approach.

  15. Use of along-track magnetic field differences in lithospheric field modelling

    OpenAIRE

    Kotsiaros, Stavros; Finlay, Chris; Olsen, Nils

    2015-01-01

    We demonstrate that first differences of polar orbiting satellite magnetic data in the along-track direction can be used to obtain high resolution models of the lithospheric field. Along-track differences approximate the north–south magnetic field gradients for non-polar latitudes. In a test case, using 2 yr of low altitude data from the CHAMP satellite, we show that use of along-track differences of vector field data results in an enhanced recovery of the small scale lithospheric field, comp...

  16. Solid-state diffusion in amorphous zirconolite

    Energy Technology Data Exchange (ETDEWEB)

    Yang, C.; Dove, M. T.; Trachenko, K. [School of Physics and Astronomy, Queen Mary University of London, Mile End Road, London E1 4NS (United Kingdom); Zarkadoula, E. [School of Physics and Astronomy, Queen Mary University of London, Mile End Road, London E1 4NS (United Kingdom); Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6138 (United States); Todorov, I. T. [STFC Daresbury Laboratory, Warrington WA4 1EP (United Kingdom); Geisler, T. [Steinmann-Institut für Geologie, Mineralogie und Paläontologie, University of Bonn, D-53115 Bonn (Germany); Brazhkin, V. V. [Institute for High Pressure Physics, RAS, 142190 Moscow (Russian Federation)

    2014-11-14

    We discuss how structural disorder and amorphization affect solid-state diffusion, and consider zirconolite as a currently important case study. By performing extensive molecular dynamics simulations, we disentangle the effects of amorphization and density, and show that a profound increase of solid-state diffusion takes place as a result of amorphization. Importantly, this can take place at the same density as in the crystal, representing an interesting general insight regarding solid-state diffusion. We find that decreasing the density in the amorphous system increases pre-factors of diffusion constants, but does not change the activation energy in the density range considered. We also find that atomic species in zirconolite are affected differently by amorphization and density change. Our microscopic insights are relevant for understanding how solid-state diffusion changes due to disorder and for building predictive models of operation of materials to be used to encapsulate nuclear waste.

  17. Systematic and Integrated Approach to Tropical Cyclone Track Forecasting. Part 3. Traits Knowledge Base for JTWC Track Forecast Models in the Western North Pacific

    National Research Council Canada - National Science Library

    Carr, Lester

    1999-01-01

    .... The indications and characteristics of these frequently recurring error mechanisms in the forecast tracks and fields of the models are thoroughly documented and one or more illustrative case studies...

  18. Use of along-track magnetic field differences in lithospheric field modelling

    DEFF Research Database (Denmark)

    Kotsiaros, Stavros; Finlay, Chris; Olsen, Nils

    2015-01-01

    , using 2 yr of low altitude data from the CHAMP satellite, we show that use of along-track differences of vector field data results in an enhanced recovery of the small scale lithospheric field, compared to the use of the vector field data themselves. We show that the along-track technique performs......, will be important in building the next generation of lithospheric field models....

  19. Influence of uneven rail irregularities on the dynamic response of the railway track using a three-dimensional model of the vehicle-track system

    Science.gov (United States)

    Naeimi, Meysam; Zakeri, Jabbar Ali; Esmaeili, Morteza; Shadfar, Morad

    2015-01-01

    A mathematical model of the vehicle-track interaction is developed to investigate the coupled behaviour of vehicle-track system, in the presence of uneven irregularities at left/right rails. The railway vehicle is simplified as a 3D multi-rigid-body model, and the track is treated as the two parallel beams on a layered discrete support system. Besides the car-body, the bogies and the wheel sets, the sleepers are assumed to have roll degree of freedom, in order to simulate the in-plane rotation of the components. The wheel-rail interface is treated using a nonlinear Hertzian contact model, coupling the mathematical equations of the vehicle-track systems. The dynamic interaction of the entire system is numerically studied in time domain, employing Newmark's integration method. The track irregularity spectra of both the left/right rails are taken into account, as the inputs of dynamic excitations. The dynamic responses of the track system induced by such irregularities are obtained, particularly in terms of the vertical (bounce) and roll displacements. The numerical model of the present research is validated using several benchmark models reported in the literature, for both the smooth and unsmooth track conditions. Four sample profiles of the measured rail irregularities are considered as the case studies of excitation sources, examining their influences on the dynamic behaviour of the coupled system. The results of numerical simulations demonstrate that the motion of track system is significantly influenced by the presence of uneven irregularities in left/right rails. Dynamic response of the sleepers in the roll direction becomes more sensitive to the rail irregularities, as the unevenness severity of the parallel profiles (quantitative difference between left and right rail spectra) is increased. The severe geometric deformation of the track in the bounce-pitch-roll directions is mainly related to such profile unevenness (cross-level) in left/right rails.

  20. Indoor Localisation Using a Context-Aware Dynamic Position Tracking Model

    Directory of Open Access Journals (Sweden)

    Montserrat Ros

    2012-01-01

    Full Text Available Indoor wireless localisation is a widely sought feature for use in logistics, health, and social networking applications. Low-powered localisation will become important for the next generation of pervasive media applications that operate on mobile platforms. We present an inexpensive and robust context-aware tracking system that can track the position of users in an indoor environment, using a wireless smart meter network. Our context-aware tracking system combines wireless trilateration with a dynamic position tracking model and a probability density map to estimate indoor positions. The localisation network consisted of power meter nodes placed at known positions in a building. The power meter nodes are tracked by mobile nodes which are carried by users to localise their position. We conducted an extensive trial of the context-aware tracking system and performed a comparison analysis with existing localisation techniques. The context-aware tracking system was able to localise a person's indoor position with an average error of 1.21 m.

  1. Amorphous Gyroscopic Topological Metamaterials

    Science.gov (United States)

    Mitchell, Noah P.; Nash, Lisa M.; Hexner, Daniel; Turner, Ari M.; Irvine, William T. M.

    Mechanical topological metamaterials display striking mechanical responses, such as unidirectional surface modes that are impervious to disorder. This behavior arises from the topology of their vibrational spectra. All examples of topological metamaterials to date are finely-tuned structures such as crystalline lattices or jammed packings. Here, we present robust recipes for building amorphous topological metamaterials with arbitrary underlying structure and no long-range order. Using interacting gyroscopes as a model system, we demonstrate through experiment, simulation, and theoretical methods that the local geometry and interactions are sufficient to generate topological mobility gaps, allowing for spatially-resolved, real-space calculations of the Chern number. The robustness of our approach enables the design and self-assembly of non-crystalline materials with protected, unidirectional waveguides on the micro and macro scale.

  2. Three-dimensional elasto-plastic soil modelling and analysis of sauropod tracks

    Directory of Open Access Journals (Sweden)

    Eugenio Sanz

    2016-06-01

    Full Text Available This paper reports the use of FEA (Finite Element Analysis to model dinosaur tracks. Satisfactory reproductions of sauropod ichnites were simulated using 3D numerical models of the elasto-plastic behaviour of soils. Though the modelling was done of ichnites in situ at the Miraflores I tracksite (Soria, Spain, the methodology could be applied to other tracksites to improve their ichnological interpretation and better understand how the type and state of the trodden sediment at the moment the track is created is a fundamental determinant of the morphology of the ichnite. The results obtained explain why the initial and commonly adopted hypothesis—that soft sediments become progressively more rigid and resistant at depth—is not appropriate at this tracksite. We explain why it is essential to consider a more rigid superficial layer (caused by desiccation overlying a softer layer that is extruded to form a displacement rim. Adult sauropods left trackways behind them. These tracks could be filled up with water due to phreatic level was close to the ground surface. The simulation provides us with a means to explain the differences between similar tracks (of different depths; with or without displacement rims in the various stratigraphic layers of the tracksite and to explain why temporary and variable conditions of humidity lead to these differences in the tracks. The simulations also demonstrate that track depth alone is insufficient to differentiate true tracks from undertracks and that other discrimination criteria need to be taken into account. The scarcity of baby sauropod tracks is explained because they are shallow and easily eroded.

  3. A comprehensive model of the railway wheelset-track interaction in curves

    Science.gov (United States)

    Martínez-Casas, José; Di Gialleonardo, Egidio; Bruni, Stefano; Baeza, Luis

    2014-09-01

    Train-track interaction has been extensively studied in the last 40 years at least, leading to modelling approaches that can deal satisfactorily with many dynamic problems arising at the wheel/rail interface. However, the available models are usually not considering specifically the running dynamics of the vehicle in a curve, whereas a number of train-track interaction phenomena are specific to curve negotiation. The aim of this paper is to define a model for a flexible wheelset running on a flexible curved track. The main novelty of this work is to combine a trajectory coordinate set with Eulerian modal coordinates; the former permits to consider curved tracks, and the latter models the small relative displacements between the trajectory frame and the solid. In order to reduce the computational complexity of the problem, one single flexible wheelset is considered instead of one complete bogie, and suitable forces are prescribed at the primary suspension seats so that the mean values of the creepages and contact forces are consistent with the low frequency curving dynamics of the complete vehicle. The wheelset model is coupled to a cyclic track model having constant curvature by means of a wheel/rail contact model which accounts for the actual geometry of the contacting profiles and for the nonlinear relationship between creepages and creep forces. The proposed model can be used to analyse a variety of dynamic problems for railway vehicles, including rail corrugation and wheel polygonalisation, squeal noise, numerical estimation of the wheelset service loads. In this paper, simulation results are presented for some selected running conditions to exemplify the application of the model to the study of realistic train-track interaction cases and to point out the importance of curve negotiation effects specifically addressed in the work.

  4. New approach of modeling charged particles track development in CR-39 detectors

    International Nuclear Information System (INIS)

    Azooz, A.A.; Hermsdorf, D.; Al-Jubbori, M.A.

    2013-01-01

    In this work, previous modeling of protons and alpha particles track length development in CR-39 solid state nuclear track detectors SSNTD is modified and further extended. The extension involved the accommodation of heavier ions into the model. These ions include deuteron, lithium, boron, carbon, nitrogen and oxygen ions. The new modeling does not contain any case sensitive free fitting parameters. Model calculation results are found to be in good agreement with both experimental data and SRIM software range energy dependence predictions. The access to a single unified and differentiable track length development equation results in the ability to obtain direct results for track etching rates. - Highlights: • New modeling of ions track length evolution measured by different authors. • Ions considered are p, d, α, Li, B, C, N, O. • Equations obtained to describe L(t) and etch rate for all ions at wide energy range. • Equations obtained do not involve any free fitting parameters. • Ions range values obtained compare well with results of SRIM software

  5. A hidden Markov movement model for rapidly identifying behavioral states from animal tracks.

    Science.gov (United States)

    Whoriskey, Kim; Auger-Méthé, Marie; Albertsen, Christoffer M; Whoriskey, Frederick G; Binder, Thomas R; Krueger, Charles C; Mills Flemming, Joanna

    2017-04-01

    Electronic telemetry is frequently used to document animal movement through time. Methods that can identify underlying behaviors driving specific movement patterns can help us understand how and why animals use available space, thereby aiding conservation and management efforts. For aquatic animal tracking data with significant measurement error, a Bayesian state-space model called the first-Difference Correlated Random Walk with Switching (DCRWS) has often been used for this purpose. However, for aquatic animals, highly accurate tracking data are now becoming more common. We developed a new hidden Markov model (HMM) for identifying behavioral states from animal tracks with negligible error, called the hidden Markov movement model (HMMM). We implemented as the basis for the HMMM the process equation of the DCRWS, but we used the method of maximum likelihood and the R package TMB for rapid model fitting. The HMMM was compared to a modified version of the DCRWS for highly accurate tracks, the DCRWSNOME, and to a common HMM for animal tracks fitted with the R package moveHMM. We show that the HMMM is both accurate and suitable for multiple species by fitting it to real tracks from a grey seal, lake trout, and blue shark, as well as to simulated data. The HMMM is a fast and reliable tool for making meaningful inference from animal movement data that is ideally suited for ecologists who want to use the popular DCRWS implementation and have highly accurate tracking data. It additionally provides a groundwork for development of more complex modeling of animal movement with TMB. To facilitate its uptake, we make it available through the R package swim.

  6. THE BASIS OF MATHEMATICAL DESCRIPTION FOR WAVE MODEL OF STRESSES PROPAGATION IN RAILWAY TRACK

    Directory of Open Access Journals (Sweden)

    D. M. Kurhan

    2016-10-01

    Full Text Available Purpose. Modern scientific research has repeatedly cited practical examples of the dynamic effects of railway track operation that go beyond the static calculation schemes. For the track sections where the train speed is approaching to the velocity of wave propagation in the slab track layers such issues are of particular relevance. An adequate tool for the study of such issues can be the use of the wave theory of stress propagation. The purpose of the article is the creation of a mathematical description of the basic principles of the stress propagation wave model in the railway track, which can be used as a basis for the practical development of the relevant calculation system. Methodology. The model of stress-strain states of the railway track on the basis of the stress wave propagation theory is to bring together the equations of the geometry of the outline of the space systems that is involved in the interaction at a given time, and the dynamic equilibrium equations of deformation. The solution is based on the use of the laws of the theory of elasticity. The wave front is described by an ellipsoid equation. When determining the variation in time of the surface position of the ellipsoid a vector approach is used. Findings. The geometry equations of the wave motion determine the volumes of material layers of the slab track involved in the interaction at a given time. The dynamic equilibrium determination of the deformed condition of the space bounded by the wave front makes it possible to calculate both the stresses and strains, and their changes during the time of the load perception. Thus, mathematical descriptions of the processes that occur in the perception of the load by the elements of railway track at high speeds were obtained. Originality. The simulation tasks of the track and rolling stock interaction, in particular taking into account the dynamic deflection of slab track were further developed. For the first time the article

  7. Hidden Markov model tracking of continuous gravitational waves from young supernova remnants

    Science.gov (United States)

    Sun, L.; Melatos, A.; Suvorova, S.; Moran, W.; Evans, R. J.

    2018-02-01

    Searches for persistent gravitational radiation from nonpulsating neutron stars in young supernova remnants are computationally challenging because of rapid stellar braking. We describe a practical, efficient, semicoherent search based on a hidden Markov model tracking scheme, solved by the Viterbi algorithm, combined with a maximum likelihood matched filter, the F statistic. The scheme is well suited to analyzing data from advanced detectors like the Advanced Laser Interferometer Gravitational Wave Observatory (Advanced LIGO). It can track rapid phase evolution from secular stellar braking and stochastic timing noise torques simultaneously without searching second- and higher-order derivatives of the signal frequency, providing an economical alternative to stack-slide-based semicoherent algorithms. One implementation tracks the signal frequency alone. A second implementation tracks the signal frequency and its first time derivative. It improves the sensitivity by a factor of a few upon the first implementation, but the cost increases by 2 to 3 orders of magnitude.

  8. Customer service model for waste tracking at Los Alamos National Laboratory

    International Nuclear Information System (INIS)

    Dorries, Alison M.; Montoya, Andrew J.; Ashbaugh, Andrew E.

    2010-01-01

    The deployment of any new software system in a production facility will always face multiple hurtles in reaching a successful acceptance. However, a new waste tracking system was required at the plutonium processing facility at Los Alamos National Laboratory (LANL) where waste processing must be integrated to handle Special Nuclear Materials tracking requirements. Waste tracking systems can enhance the processing of waste in production facilities when the system is developed with a focus on customer service throughout the project life cycle. In March 2010 Los Alamos National Laboratory Waste Technical Services (WTS) replaced the aging systems and infrastructure that were being used to support the plutonium processing facility. The Waste Technical Services (WTS) Waste Compliance and Tracking System (WCATS) Project Team, using the following customer service model, succeeded in its goal to meet all operational and regulatory requirements, making waste processing in the facility more efficient while partnering with the customer.

  9. Interface-tracking electro-hydrodynamic model for droplet coalescence

    Science.gov (United States)

    Crowl Erickson, Lindsay; Noble, David

    2012-11-01

    Many fluid-based technologies rely on electrical fields to control the motion of droplets, e.g. micro-fluidic devices for high-speed droplet sorting, solution separation for chemical detectors, and purification of biodiesel fuel. Precise control over droplets is crucial to these applications. However, electric fields can induce complex and unpredictable fluid dynamics. Recent experiments (Ristenpart et al. 2009) have demonstrated that oppositely charged droplets bounce rather than coalesce in the presence of strong electric fields. Analytic hydrodynamic approximations for interfaces become invalid near coalescence, and therefore detailed numerical simulations are necessary. We present a conformal decomposition finite element (CDFEM) interface-tracking method for two-phase flow to demonstrate electro-coalescence. CDFEM is a sharp interface method that decomposes elements along fluid-fluid boundaries and uses a level set function to represent the interface. The electro-hydrodynamic equations solved allow for convection of charge and charge accumulation at the interface, both of which may be important factors for the pinch-off dynamics in this parameter regime.

  10. Analysing Possible Applications for Available Mathematical Models of Tracked Vehicle Movement Over the Rough Terrain to Examine Tracked Chain Dynamic Processes

    Directory of Open Access Journals (Sweden)

    M. E. Lupyan

    2014-01-01

    Full Text Available The article offered for consideration provides a survey of methods to study a tracked vehicle movement over unpaved grounds and obstacles using various software systems. The relevant issue is to optimize chassis elements of a caterpillar at the design stage. The challenges, engineers face using different methods to study the tracked vehicle elements, are given. Advantages of using simulation to study a state of the various components of the loaded chassis are described. Beside, an important and relevant issue is brought up i.e. modeling a vehicle movement in real time.While writing an article, different modeling methods for an interaction between a tracked vehicle chassis and an underlying subgrade used both in domestic and in foreign practice have been analysed. The applied analytical assumptions in creating these models and their basic elements are described. The way to specify an interaction between the track and road wheels of a caterpillar, crawler belt specification, and interaction between its elements have been analysed in detail as well. Special attention was also paid to the various ways of specifying the subgrade both in planar models and in models enabling us to study all chassis elements of a caterpillar as a whole.In addition to the classical simulation of tracked vehicle movement used to analyse Ride qualities of tracked vehicle and loaded state of various chassis elements, is offered a model used to simulate a movement coil in real time.The article presents advantages and disadvantages of different models of movement in terms of engineering analysis of caterpillar elements. A task to develop a simulation model of caterpillar movement is set. Requirements for a model in case of its use in engineering analysis of chassis elements of a caterpillar are defined. A problem of a lack of the single technique to conduct engineering analysis of tracked vehicle chassis is noted. 

  11. Amorphous iron (II) carbonate

    DEFF Research Database (Denmark)

    Sel, Ozlem; Radha, A.V.; Dideriksen, Knud

    2012-01-01

    Abstract The synthesis, characterization and crystallization energetics of amorphous iron (II) carbonate (AFC) are reported. AFC may form as a precursor for siderite (FeCO3). The enthalpy of crystallization (DHcrys) of AFC is similar to that of amorphous magnesium carbonate (AMC) and more...

  12. A Deep-Structured Conditional Random Field Model for Object Silhouette Tracking.

    Directory of Open Access Journals (Sweden)

    Mohammad Javad Shafiee

    Full Text Available In this work, we introduce a deep-structured conditional random field (DS-CRF model for the purpose of state-based object silhouette tracking. The proposed DS-CRF model consists of a series of state layers, where each state layer spatially characterizes the object silhouette at a particular point in time. The interactions between adjacent state layers are established by inter-layer connectivity dynamically determined based on inter-frame optical flow. By incorporate both spatial and temporal context in a dynamic fashion within such a deep-structured probabilistic graphical model, the proposed DS-CRF model allows us to develop a framework that can accurately and efficiently track object silhouettes that can change greatly over time, as well as under different situations such as occlusion and multiple targets within the scene. Experiment results using video surveillance datasets containing different scenarios such as occlusion and multiple targets showed that the proposed DS-CRF approach provides strong object silhouette tracking performance when compared to baseline methods such as mean-shift tracking, as well as state-of-the-art methods such as context tracking and boosted particle filtering.

  13. Maximum Correntropy Criterion Kalman Filter for α-Jerk Tracking Model with Non-Gaussian Noise

    Directory of Open Access Journals (Sweden)

    Bowen Hou

    2017-11-01

    Full Text Available As one of the most critical issues for target track, α -jerk model is an effective maneuver target track model. Non-Gaussian noises always exist in the track process, which usually lead to inconsistency and divergence of the track filter. A novel Kalman filter is derived and applied on α -jerk tracking model to handle non-Gaussian noise. The weighted least square solution is presented and the standard Kalman filter is deduced firstly. A novel Kalman filter with the weighted least square based on the maximum correntropy criterion is deduced. The robustness of the maximum correntropy criterion is also analyzed with the influence function and compared with the Huber-based filter, and, moreover, the kernel size of Gaussian kernel plays an important role in the filter algorithm. A new adaptive kernel method is proposed in this paper to adjust the parameter in real time. Finally, simulation results indicate the validity and the efficiency of the proposed filter. The comparison study shows that the proposed filter can significantly reduce the noise influence for α -jerk model.

  14. A generative Bezier curve model for surf-zone tracking in coastal image sequences

    CSIR Research Space (South Africa)

    Burke, Michael G

    2017-09-01

    Full Text Available This work introduces a generative Bezier curve model suitable for surf-zone curve tracking in coastal image sequences. The model combines an adaptive curve parametrised by control points governed by local random walks with a global sinusoidal motion...

  15. An extended target tracking model with multiple random matrices and unified kinematics

    OpenAIRE

    Granstrom, Karl

    2014-01-01

    This paper presents a model for tracking of extended targets, where each target is represented by a given number of elliptic subobjects. A gamma Gaussian inverse Wishart implementation is derived, and necessary approximations are suggested to alleviate the data association complexity. A simulation study shows the merits of the model compared to previous work on the topic.

  16. A non-parametric hierarchical model to discover behavior dynamics from tracks

    NARCIS (Netherlands)

    Kooij, J.F.P.; Englebienne, G.; Gavrila, D.M.

    2012-01-01

    We present a novel non-parametric Bayesian model to jointly discover the dynamics of low-level actions and high-level behaviors of tracked people in open environments. Our model represents behaviors as Markov chains of actions which capture high-level temporal dynamics. Actions may be shared by

  17. A climatological model of North Indian Ocean tropical cyclone genesis, tracks and landfall

    Science.gov (United States)

    Wahiduzzaman, Mohammad; Oliver, Eric C. J.; Wotherspoon, Simon J.; Holbrook, Neil J.

    2017-10-01

    Extensive damage and loss of life can be caused by tropical cyclones (TCs) that make landfall. Modelling of TC landfall probability is beneficial to insurance/re-insurance companies, decision makers, government policy and planning, and residents in coastal areas. In this study, we develop a climatological model of tropical cyclone genesis, tracks and landfall for North Indian Ocean (NIO) rim countries based on kernel density estimation, a generalised additive model (GAM) including an Euler integration step, and landfall detection using a country mask approach. Using a 35-year record (1979-2013) of tropical cyclone track observations from the Joint Typhoon Warning Centre (part of the International Best Track Archive Climate Stewardship Version 6), the GAM is fitted to the observed cyclone track velocities as a smooth function of location in each season. The distribution of cyclone genesis points is approximated by kernel density estimation. The model simulated TCs are randomly selected from the fitted kernel (TC genesis), and the cyclone paths (TC tracks), represented by the GAM together with the application of stochastic innovations at each step, are simulated to generate a suite of NIO rim landfall statistics. Three hindcast validation methods are applied to evaluate the integrity of the model. First, leave-one-out cross validation is applied whereby the country of landfall is determined by the majority vote (considering the location by only highest percentage of landfall) from the simulated tracks. Second, the probability distribution of simulated landfall is evaluated against the observed landfall. Third, the distances between the point of observed landfall and simulated landfall are compared and quantified. Overall, the model shows very good cross-validated hindcast skill of modelled landfalling cyclones against observations in each of the NIO tropical cyclone seasons and for most NIO rim countries, with only a relatively small difference in the percentage of

  18. Improved design of constrained model predictive tracking control for batch processes against unknown uncertainties.

    Science.gov (United States)

    Wu, Sheng; Jin, Qibing; Zhang, Ridong; Zhang, Junfeng; Gao, Furong

    2017-07-01

    In this paper, an improved constrained tracking control design is proposed for batch processes under uncertainties. A new process model that facilitates process state and tracking error augmentation with further additional tuning is first proposed. Then a subsequent controller design is formulated using robust stable constrained MPC optimization. Unlike conventional robust model predictive control (MPC), the proposed method enables the controller design to bear more degrees of tuning so that improved tracking control can be acquired, which is very important since uncertainties exist inevitably in practice and cause model/plant mismatches. An injection molding process is introduced to illustrate the effectiveness of the proposed MPC approach in comparison with conventional robust MPC. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

  19. Comparison of model independent control and tracking with standard control techniques

    Science.gov (United States)

    Schwartz, Ira B.; Triandaf, Ioana A.

    1993-12-01

    This paper highlights some of the new contributions nonlinear dynamics has made in the areas of control and tracking. In particular, emphasis is placed on the model independent approach to control and tracking: The connections between the classical control and the control based on time series embedding methods are made. In experiments of control, our approach does not necessarily imply new equipment is needed in the loop. Rather, it is the control settings which are constructed off-line so that location of the control point and gain are determined without trial and error. Using the model independent approach also allows one to locate and control many other accessible unstable phenomena without having to construct a global nonlinear model. Tracking gives a constructive approach to control inaccessible states, as well as maps out the global regions of phase space.

  20. Study on Vehicle Track Model in Road Curved Section Based on Vehicle Dynamic Characteristics

    Directory of Open Access Journals (Sweden)

    Ren Yuan-Yuan

    2012-01-01

    Full Text Available Plenty of experiments and data analysis of vehicle track type in road curved section show that the deviation and the crossing characteristics of vehicle track paths are directly related to the driving stability and security. In this connection, the concept of driving trajectory in curved section was proposed, six track types were classified and defined, and furthermore their characteristic features were determined. Most importantly, considering curve geometry and vehicle dynamic characteristics, each trajectory model was established, respectively, and the optimum driving trajectory models were finally determined based on the crucial factors of vehicle yaw rate, which was also the most important factor that impacts vehicle’s handling stability. Through it all, MATLAB was used to simulate and verify the correctness of models. Finally, this paper comes to the conclusion that normal trajectory and cutting trajectory are the optimum driving trajectories.

  1. A Hidden Markov Movement Model for rapidly identifying behavioral states from animal tracks

    DEFF Research Database (Denmark)

    Whoriskey, Kim; Auger-Méthé, Marie; Albertsen, Christoffer Moesgaard

    2017-01-01

    1. Electronic telemetry is frequently used to document animal movement through time. Methods that can identify underlying behaviors driving specific movement patterns can help us understand how and why animals use available space, thereby aiding conservation and management efforts. For aquatic...... animal tracking data with significant measurement error, a Bayesian state-space model called the first-Difference Correlated Random Walk with Switching (DCRWS) has often been used for this purpose. However, for aquatic animals, highly accurate tracking data of animal movement are now becoming more common....... 2. We developed a new Hidden Markov Model (HMM) for identifying behavioral states from animal tracks with negligible error, which we called the Hidden Markov Movement Model (HMMM). We implemented as the basis for the HMMM the process equation of the DCRWS, but we used the method of maximum...

  2. A numerical model for the thermal history of rocks based on confined horizontal fission tracks

    DEFF Research Database (Denmark)

    Jensen, Peter Klint; Hansen, Kirsten; Kunzendorf, Helmar

    1992-01-01

    A numerical model for determination of the thermal history of rocks is presented. It is shown that the thermal history may be uniquely determined as a piece-by-piece linear function on the basis of etched confined, horizontal fission track length distributions, their surface densities...... measured in transmitted light are biased favouring short tracks compared with measurements in reflected light. Testing of the model is performed on apatites from a tuffaceous sandstone from Bornholm (Denmark) yielding an estimate of the thermal history for the period of about 280 Ma back in time....

  3. An Adaptive Neural Mechanism with a Lizard Ear Model for Binaural Acoustic Tracking

    DEFF Research Database (Denmark)

    Shaikh, Danish; Manoonpong, Poramate

    2016-01-01

    expensive algorithms. We present a novel bioinspired solution to acoustic tracking that uses only two microphones. The system is based on a neural mechanism coupled with a model of the peripheral auditory system of lizards. The peripheral auditory model provides sound direction information which the neural...... mechanism uses to learn the target’s velocity via fast correlation-based unsupervised learning. Simulation results for tracking a pure tone acoustic target moving along a semi-circular trajectory validate our approach. Three different angular velocities in three separate trials were employed...

  4. Microenvironment Tracker (MicroTrac) Model helps track air quality

    Science.gov (United States)

    MicroTrac is a model that uses global positioning system (GPS) data to estimate time of day and duration that people spend in different microenvironments (e.g., indoors and outdoors at home, work, school).

  5. Elucidating an Amorphous Form Stabilization Mechanism for Tenapanor Hydrochloride: Crystal Structure Analysis Using X-ray Diffraction, NMR Crystallography, and Molecular Modeling.

    Science.gov (United States)

    Nilsson Lill, Sten O; Widdifield, Cory M; Pettersen, Anna; Svensk Ankarberg, Anna; Lindkvist, Maria; Aldred, Peter; Gracin, Sandra; Shankland, Norman; Shankland, Kenneth; Schantz, Staffan; Emsley, Lyndon

    2018-03-12

    By the combined use of powder and single-crystal X-ray diffraction, solid-state NMR, and molecular modeling, the crystal structures of two systems containing the unusually large tenapanor drug molecule have been determined: the free form, ANHY, and a dihydrochloride salt form, 2HCl. Dynamic nuclear polarization (DNP) assisted solid-state NMR (SSNMR) crystallography investigations were found essential for the final assignment and were used to validate the crystal structure of ANHY. From a structural informatics analysis of ANHY and 2HCl, conformational ring differences in one part of the molecule were observed which influence the relative orientation of a methyl group on a ring nitrogen and thereby impact the crystallizability of the dihydrochloride salt. From quantum chemistry calculations, the dynamics between different ring conformations in tenapanor is predicted to be fast. Addition of HCl to tenapanor results in general in a mixture of protonated ring conformers and hence a statistical mix of diastereoisomers which builds up the amorphous form, a-2HCl. This was qualitatively verified by 13 C CP/MAS NMR investigations of the amorphous form. Thus, to form any significant amount of the crystalline material 2HCl, which originates from the minor (i.e., energetically less stable) ring conformations, one needs to involve nitrogen deprotonation to allow exchange between the minor and major conformations of ANHY in solution. Thus, by controlling the solution pH value to well below the p K a of ANHY, the equilibrium between ANHY and 2HCl can be controlled and by this mechanism the crystallization of 2HCl can be avoided and the amorphous form of the dichloride salt can therefore be stabilized.

  6. IMPACT - Integrated Modeling of Perturbations in Atmospheres for Conjunction Tracking

    Science.gov (United States)

    2013-09-01

    modeling with Test Particle and Direct Simulation Monte Carlo methods to accurately account for changes in density, chemical composition, temperature and...carrying on-board GPS receivers. b) Cubesats , many of which are similar in terms of mass, volume, shape, and surface materials and hence are good test...dimensional model that solves the full Navier-Stokes equations for density, velocity, and temperature for a number of neutral and charged components. To

  7. A hand tracking algorithm with particle filter and improved GVF snake model

    Science.gov (United States)

    Sun, Yi-qi; Wu, Ai-guo; Dong, Na; Shao, Yi-zhe

    2017-07-01

    To solve the problem that the accurate information of hand cannot be obtained by particle filter, a hand tracking algorithm based on particle filter combined with skin-color adaptive gradient vector flow (GVF) snake model is proposed. Adaptive GVF and skin color adaptive external guidance force are introduced to the traditional GVF snake model, guiding the curve to quickly converge to the deep concave region of hand contour and obtaining the complex hand contour accurately. This algorithm realizes a real-time correction of the particle filter parameters, avoiding the particle drift phenomenon. Experimental results show that the proposed algorithm can reduce the root mean square error of the hand tracking by 53%, and improve the accuracy of hand tracking in the case of complex and moving background, even with a large range of occlusion.

  8. Modelling of Railway Track Temperature Regime with Real Heat-Technical Values for Different Climatic Characteristics

    Science.gov (United States)

    Hodás, Stanislav; Pultznerová, Alžbeta

    2017-12-01

    High quality of railway track construction is a major priority. One of the quality elements is the resistance to load of railway formation with individual structural layers caused by negative temperatures during the critical freezing period of winter. Numerical modelling allows obtaining more control outputs at different climatic loads. The presented paper shows the load of railway track model with different variants of climate and shows the importance in the designing of the non-transport load under negative temperatures, i.e. observation of transition of the zero isotherm through the layers of railway subgrade. If the subgrade layers of the railway formation are built with high quality and durability then the axis of the track will keep its geometric spatial position during the long-time operation.

  9. In-Situ Residual Tracking in Reduced Order Modelling

    Directory of Open Access Journals (Sweden)

    Joseph C. Slater

    2002-01-01

    Full Text Available Proper orthogonal decomposition (POD based reduced-order modelling is demonstrated to be a weighted residual technique similar to Galerkin's method. Estimates of weighted residuals of neglected modes are used to determine relative importance of neglected modes to the model. The cumulative effects of neglected modes can be used to estimate error in the reduced order model. Thus, once the snapshots have been obtained under prescribed training conditions, the need to perform full-order simulations for comparison is eliminates. This has the potential to allow the analyst to initiate further training when the reduced modes are no longer sufficient to accurately represent the predominant phenomenon of interest. The response of a fluid moving at Mach 1.2 above a panel to a forced localized oscillation of the panel at and away from the training operating conditions is used to demonstrate the evaluation method.

  10. Physics of amorphous metals

    CERN Document Server

    Kovalenko, Nikolai P; Krey, Uwe

    2008-01-01

    The discovery of bulk metallic glasses has led to a large increase in the industrial importance of amorphous metals, and this is expected to continue. This book is the first to describe the theoretical physics of amorphous metals, including the important theoretical development of the last 20 years.The renowned authors stress the universal aspects in their description of the phonon or magnon low-energy excitations in the amorphous metals, e.g. concerning the remarkable consequences of the properties of these excitations for the thermodynamics at low and intermediate temperatures. Tunneling

  11. Amorphization within the tablet

    DEFF Research Database (Denmark)

    Doreth, Maria; Hussein, Murtadha Abdul; Priemel, Petra A.

    2017-01-01

    , the feasibility of microwave irradiation to prepare amorphous solid dispersions (glass solutions) in situ was investigated. Indomethacin (IND) and polyvinylpyrrolidone K12 (PVP) were tableted at a 1:2 (w/w) ratio. In order to study the influence of moisture content and energy input on the degree of amorphization......, tablet formulations were stored at different relative humidity (32, 43 and 54% RH) and subsequently microwaved using nine different power-time combinations up to a maximum energy input of 90 kJ. XRPD results showed that up to 80% (w/w) of IND could be amorphized within the tablet. mDSC measurements...

  12. The Effect of Satellite Track Masking on Simulated Cloud Satellite Data in a Global Atmospheric Model

    Science.gov (United States)

    Eichmann, A.; da Silva, A.; Norris, P. M.; Molod, A.; Auer, B.

    2013-12-01

    The CFMIP Observation Simulator Package (COSP) simulates data provided by cloud-observing satellites and products based on the hydrometeor properties in an atmospheric model in order to provide an objective means to compare cloud properties between models. COSP also facilitates comparisons between models and satellite products, but as provided it examines the entire model domain whereas satellites cover only the swath of their respective orbital tracks. This temporal and spatial mismatch in data coverage may introduce biases in time-averaged model cloud fields. Here the data generated by COSP from a year-long integration of the GEOS-5 Earth System Model are masked with the respective orbital tracks of the satellites and compared to the unmasked fields to determine what biases domain-wide coverage may induce.

  13. Robot Visual Tracking via Incremental Self-Updating of Appearance Model

    Directory of Open Access Journals (Sweden)

    Danpei Zhao

    2013-09-01

    Full Text Available This paper proposes a target tracking method called Incremental Self-Updating Visual Tracking for robot platforms. Our tracker treats the tracking problem as a binary classification: the target and the background. The greyscale, HOG and LBP features are used in this work to represent the target and are integrated into a particle filter framework. To track the target over long time sequences, the tracker has to update its model to follow the most recent target. In order to deal with the problems of calculation waste and lack of model-updating strategy with the traditional methods, an intelligent and effective online self-updating strategy is devised to choose the optimal update opportunity. The strategy of updating the appearance model can be achieved based on the change in the discriminative capability between the current frame and the previous updated frame. By adjusting the update step adaptively, severe waste of calculation time for needless updates can be avoided while keeping the stability of the model. Moreover, the appearance model can be kept away from serious drift problems when the target undergoes temporary occlusion. The experimental results show that the proposed tracker can achieve robust and efficient performance in several benchmark-challenging video sequences with various complex environment changes in posture, scale, illumination and occlusion.

  14. Track structure model for damage to mammalian cell cultures during solar proton events

    Science.gov (United States)

    Cucinotta, F. A.; Wilson, J. W.; Townsend, L. W.; Shinn, J. L.; Katz, R.

    1992-01-01

    Solar proton events (SPEs) occur infrequently and unpredictably, thus representing a potential hazard to interplanetary space missions. Biological damage from SPEs will be produced principally through secondary electron production in tissue, including important contributions due to delta rays from nuclear reaction products. We review methods for estimating the biological effectiveness of SPEs using a high energy proton model and the parametric cellular track model. Results of the model are presented for several of the historically largest flares using typical levels and body shielding.

  15. Design of a Discrete Tracking Controller for a Magnetic Levitation System: A Nonlinear Rational Model Approach

    Directory of Open Access Journals (Sweden)

    Fernando Gómez-Salas

    2015-01-01

    Full Text Available This work proposes a discrete-time nonlinear rational approximate model for the unstable magnetic levitation system. Based on this model and as an application of the input-output linearization technique, a discrete-time tracking control design will be derived using the corresponding classical state space representation of the model. A simulation example illustrates the efficiency of the proposed methodology.

  16. A Brownian Bridge Movement Model to Track Mobile Targets

    Science.gov (United States)

    2016-09-01

    the probability of a pirate attack at various locations and times. In another work, Johnston (1995) applied search theory to estimate the probability...model, developed by the U.S. Naval Research Laboratory, that generates the probability that a pirate will attack at a given time and location in the... Shark onboard the carrier. It would seem that China is making remarkable progress in learning the science and art of carrier aviation and likely will

  17. Deformation data modeling through numerical models: an efficient method for tracking magma transport

    Science.gov (United States)

    Charco, M.; Gonzalez, P. J.; Galán del Sastre, P.

    2017-12-01

    Nowadays, multivariate collected data and robust physical models at volcano observatories are becoming crucial for providing effective volcano monitoring. Nevertheless, the forecast of volcanic eruption is notoriously difficult. Wthin this frame one of the most promising methods to evaluate the volcano hazard is the use of surface ground deformation and in the last decades many developments in the field of deformation modeling has been achieved. In particular, numerical modeling allows realistic media features such as topography and crustal heterogeneities to be included, although it is still very time cosuming to solve the inverse problem for near-real time interpretations. Here, we present a method that can be efficiently used to estimate the location and evolution of magmatic sources base on real-time surface deformation data and Finite Element (FE) models. Generally, the search for the best-fitting magmatic (point) source(s) is conducted for an array of 3-D locations extending below a predefined volume region and the Green functions for all the array components have to be precomputed. We propose a FE model for the pre-computation of Green functions in a mechanically heterogeneous domain which eventually will lead to a better description of the status of the volcanic area. The number of Green functions is reduced here to the number of observational points by using their reciprocity relationship. We present and test this methodology with an optimization method base on a Genetic Algorithm. Following synthetic and sensitivity test to estimate the uncertainty of the model parameters, we apply the tool for magma tracking during 2007 Kilauea volcano intrusion and eruption. We show how data inversion with numerical models can speed up the source parameters estimations for a given volcano showing signs of unrest.

  18. Transient photoconductivity in amorphous semiconductors

    International Nuclear Information System (INIS)

    Mpawenayo, P.

    1997-07-01

    Localized states in amorphous semiconductors are divided in disorder induced shallow trap levels and dangling bonds deep states. Dangling bonds are assumed here to be either neutral or charged and their energy distribution is a single gaussian. Here, it is shown analytically that transient photocurrent in amorphous semiconductors is fully controlled by charge carriers transitions between localized states for one part and tunneling hopping carriers on the other. Localized dangling bonds deep states act as non radiative recombination centres, while hopping tunnelling is assisted by the Coulomb interaction between defects sites. The half-width of defects distribution is the disorder parameter that determines the carrier hopping time between defects sites. The macroscopic time that explains the long decay response times observed will all types of amorphous semiconductors is duly thought to be temperature dependent. Basic equations developed by Longeaud and Kleider are solved for the general case of a semiconductor after photo-generation. It turns out that the transient photoconductivity decay has two components; one with short response times from carriers trap-release transitions between shallow levels and extended states and a hopping component made of inter-dependent exponentials whose time constants span in larger ranges depending on disorder. The photoconductivity hopping component appears as an additional term to be added to photocurrents derived from existing models. The results of the present study explain and complete the power law decay derived in the multiple trapping models developed 20 years ago only in the approximation of the short response time regime. The long response time regime is described by the hopping macroscopic time. The present model is verified for all samples of amorphous semiconductors known so far. Finally, it is proposed to improved the modulated photoconductivity calculation techniques by including the long-lasting hopping dark documents

  19. Amorphous Carbon: State of the Art - Proceedings of the 1st International Specialist Meeting on Amorphous Carbon (smac '97)

    Science.gov (United States)

    Silva, S. R. P.; Robertson, J.; Milne, W. I.; Amaratunga, G. A. J.

    1998-05-01

    The Table of Contents for the full book PDF is as follows: * Preface * GROWTH AND STRUCTURE * The Structure of Tetrahedral Amorphous Carbon * Growth of DLC Films and Related Structure and Properties * Deposition Mechanism of Diamond-Like Carbon * Relaxation of sp3 Bonds in Hydrogen Free Carbon Films During Growth * MODELLING * Correlations Between Microstructure and Electronic Properties in Amorphous Carbon Based Materials * Review of Monte Carlo Simulations of Diamondlike Amorphous Carbon: Bulk, Surface, and Interface Structural Properties * DEPOSITION * Preparation of Disordered Amorphous and Partially Ordered Nano Clustered Carbon Films by Arc Deposition: A Critical Review * Plasma Deposition of Diamond-Like Carbon in an ECR-RF Discharge * Deposition of Amorphous Hydrogenated Carbon-Nitrogen Films by PECVD Using Several Hydrocarbon / Nitrogen Containing Gas Mixtures * ELECTRONIC STRUCTURE * 'Defects' and Their Detection in a-C and a-C:H * Valence Band and Gap State Spectroscopy of Amorphous Carbon by Photoelectron Emission Techniques * Photoluminescence Spectroscopy: A Probe for Inhomogeneous Structure in Polymer-Like Amorphous Carbon * Raman Characterization of Amorphous and Nanocrystalline sp3 Bonded Structures * Ultraviolet Raman Spectroscopy of Tetrahedral Amorphous Carbon Thin Films * Excitation Energy Dependent Raman and Photoluminescence Spectra of Hydrogenated Amorphous Carbon * MECHANICAL PROPERTIES * Pulsed Laser Deposited a-C: Growth, Structure and Mechanical Properties * Mechanical Properties of Laser-Assisted Deposited Amorphous Carbon Films * Mechanical and Morphology Study on Tetrahedral Amorphous Carbon Films * Time-Dependent Changes in the Mechanical Properties of Diamond-Like Carbon Films * ELECTRONIC PROPERTIES * Electronic Transport in Amorphous Carbon * Electronic Properties of Undoped/Doped Tetrahedral Amorphous Carbon * The Inclusion of Graphitic Nanoparticles in Semiconducting Amorphous Carbon to Enhance Electronic Transport Properties

  20. Numerical modelling of the reinforcing effect of geosynthetic material used in a ballasted railway tracks

    Czech Academy of Sciences Publication Activity Database

    Jiroušek, Ondřej; Jíra, J.; Hrdlička, Ondřej; Kunecký, Jiří; Kytýř, Daniel; Vyčichl, J.; Doktor, Tomáš

    2010-01-01

    Roč. 224, č. 4 (2010), s. 259-267 ISSN 0954-4097 Institutional research plan: CEZ:AV0Z20710524 Keywords : railway track bed * reinforcing geogrid * finite-element modelling * settlement reduction * contact analysis * ballast material Subject RIV: JN - Civil Engineering Impact factor: 0.389, year: 2010 http://journals.pepublishing.com/content/k561040632411117/

  1. Modeling human tracking error in several different anti-tank systems

    Science.gov (United States)

    Kleinman, D. L.

    1981-01-01

    An optimal control model for generating time histories of human tracking errors in antitank systems is outlined. Monte Carlo simulations of human operator responses for three Army antitank systems are compared. System/manipulator dependent data comparisons reflecting human operator limitations in perceiving displayed quantities and executing intended control motions are presented. Motor noise parameters are also discussed.

  2. Determination of optimal pacing strategy in track cycling with an energy flow model

    NARCIS (Netherlands)

    de Koning, J.J.; Bobbert, M.F.; Foster, C.

    1999-01-01

    The purpose of this study was to investigate the effect of pacing strategies on performance times in the 1000 m time trial event and the 4000 m pursuit event in track cycling. For this purpose, we simulated these events with a model based on the flow of energy in cycling. Different strategies in

  3. Tracking Problem Solving by Multivariate Pattern Analysis and Hidden Markov Model Algorithms

    Science.gov (United States)

    Anderson, John R.

    2012-01-01

    Multivariate pattern analysis can be combined with Hidden Markov Model algorithms to track the second-by-second thinking as people solve complex problems. Two applications of this methodology are illustrated with a data set taken from children as they interacted with an intelligent tutoring system for algebra. The first "mind reading" application…

  4. Density functional theory modeling of the adsorption of small analyte and indicator dye 9-(diphenylamino)acridine molecules on the surface of amorphous silica nanoparticles.

    Science.gov (United States)

    Chashchikhin, Vladimir; Rykova, Elena; Bagaturyants, Alexander

    2011-01-28

    The adsorption of small analyte molecules (H(2)O, NH(3), C(2)H(5)OH, and (CH(3))(2)CO) and an indicator dye, 9-(diphenylamino)acridine (DPAA), on the surface of amorphous silica particles is studied using electronic structure calculations at the DFT-D level of theory taking into account explicit corrections for van der Waals forces. Cluster models of three different types are used; two of them have been constructed using classical MD methods. The effect of particle size, local environment, and the choice of the exchange-correlation functional and basis set on the adsorption energies is studied, and adsorption energies are extrapolated to nanosized clusters. It is shown that the dye is more strongly bound to amorphous silica particles than the studied analyte molecules and that the energy of DPAA adsorption increases with the particle size, being at least twice as high as the energy of analyte adsorption for nanosized clusters. Electrostatic interactions play an important role in the adsorption of acridine dyes on the surface of silica nanoparticles.

  5. Eye Tracking Meets the Process of Process Modeling: a Visual Analytic Approach

    DEFF Research Database (Denmark)

    Burattin, Andrea; Kaiser, M.; Neurauter, Manuel

    2017-01-01

    Research on the process of process modeling (PPM) studies how process models are created. It typically uses the logs of the interactions with the modeling tool to assess the modeler’s behavior. In this paper we suggest to introduce an additional stream of data (i.e., eye tracking) to improve...... diagram, heat maps, fixations distributions) both static and dynamic (i.e., movies with the evolution of the model and eye tracking data on top)....... the analysis of the PPM. We show that, by exploiting this additional source of information, we can refine the detection of comprehension phases (introducing activities such as “semantic validation” or “ problem understanding”) as well as provide more exploratory visualizations (e.g., combined modeling phase...

  6. Simulations of mixing in Inertial Confinement Fusion with front tracking and sub-grid scale models

    Science.gov (United States)

    Rana, Verinder; Lim, Hyunkyung; Melvin, Jeremy; Cheng, Baolian; Glimm, James; Sharp, David

    2015-11-01

    We present two related results. The first discusses the Richtmyer-Meshkov (RMI) and Rayleigh-Taylor instabilities (RTI) and their evolution in Inertial Confinement Fusion simulations. We show the evolution of the RMI to the late time RTI under transport effects and tracking. The role of the sub-grid scales helps capture the interaction of turbulence with diffusive processes. The second assesses the effects of concentration on the physics model and examines the mixing properties in the low Reynolds number hot spot. We discuss the effect of concentration on the Schmidt number. The simulation results are produced using the University of Chicago code FLASH and Stony Brook University's front tracking algorithm.

  7. Front tracking based modeling of the solid grain growth on the adaptive control volume grid

    Science.gov (United States)

    Seredyński, Mirosław; Łapka, Piotr

    2017-07-01

    The paper presents the micro-scale model of unconstrained solidification of the grain immersed in under-cooled liquid, based on the front tracking approach. For this length scale, the interface tracked through the domain is meant as the solid-liquid boundary. To prevent generation of huge meshes the energy transport equation is discretized on the adaptive control volume (c.v.) mesh. The coupling of dynamically changing mesh and moving front position is addressed. Preliminary results of simulation of a test case, the growth of single grain, are presented and discussed.

  8. Multiple-F0 tracking based on a high-order HMM model

    OpenAIRE

    Chang, Wei-Chen; Su, Alvin W.Y.; Yeh,, Chunghsin; Roebel, Axel; Rodet, Xavier

    2008-01-01

    cote interne IRCAM: Chang08a; None / None; National audience; This paper is about multiple-F0 tracking and the estimation of the number of harmonic source streams in music sound signals. A source stream is understood as generated from a note played by a musical instrument. A note is described by a hiddenMarkovmodel (HMM) having two states: the attack state and the sustain state. It is proposed to first perform the tracking of F0 candidates using a high-order hidden Markov model, based on a fo...

  9. Magneto-mechanical modeling study of CO-based amorphous micro- and nanowires for acoustic sensing medical applications

    Energy Technology Data Exchange (ETDEWEB)

    Atitoaie, Alexandru, E-mail: atitoaie@phys-iasi.ro [National Institute of Research and Development for Technical Physics, Iasi (Romania); Department of Physics, “Alexandru Ioan Cuza” University, 700506 Iasi (Romania); Stancu, Alexandru [Department of Physics, “Alexandru Ioan Cuza” University, 700506 Iasi (Romania); Ovari, Tibor-Adrian; Lupu, Nicoleta; Chiriac, Horia [National Institute of Research and Development for Technical Physics, Iasi (Romania)

    2016-04-01

    Magnetic nanowires are potential candidates for substituting, within enhanced cochlear implants, the role played by hair cilia from the inner ear, which are responsible for the transduction of acoustic vibrations into electric signals. The sound waves pressure that is bending the magnetic wires induces stresses that are leading to changes in magnetic properties, such as magnetization and permeability. These changes can be detected by a GMR sensor placed below the nanowire array or, in the case of different designs, by a pick-up coil wrapped around the fixed-end of the wires. For the latter case, we are studying the stress distributions caused by bending deformations using the COMSOL finite element software package. We are also proposing a theoretical method for the evaluation of magnetic permeability variation vs. induced stress dependence. The study is performed on CoFeSiB amorphous micro- and nanowires subjected to mechanical perturbations similar to the ones produced by sound pressure waves.

  10. Energy Optimal Tracking Control with Discrete Fluid Power Systems using Model Predictive Control

    DEFF Research Database (Denmark)

    Hansen, Anders Hedegaard; Asmussen, Magnus Færing; Bech, Michael Møller

    2017-01-01

    For Discrete Displacement Cylinder (DDC) drives the control task lies in choosing force level. Hence, which force level to apply and thereby which pressure level each cylinder chambers shall be connected to. The DDC system is inherently a force system why often a force reference is generated by a...... and compared to a PID like tracking controller combined with a FSA. The results indicate that the energy efficiency of position tracking DDC systems may be improved significantly by using the MPC algorithm.......For Discrete Displacement Cylinder (DDC) drives the control task lies in choosing force level. Hence, which force level to apply and thereby which pressure level each cylinder chambers shall be connected to. The DDC system is inherently a force system why often a force reference is generated...... by a tracking controller and translated into a discrete force level in a Force Shifting Algorithm (FSA). In the current paper the tracking controller and the FSA are combined in a Model Predictive Control algorithm solving the tracking problem while minimizing the energy use. Two MPC algorithms are investigated...

  11. Dynamic Modeling and Control Strategy Optimization for a Hybrid Electric Tracked Vehicle

    Directory of Open Access Journals (Sweden)

    Hong Wang

    2015-01-01

    Full Text Available A new hybrid electric tracked bulldozer composed of an engine generator, two driving motors, and an ultracapacitor is put forward, which can provide high efficiencies and less fuel consumption comparing with traditional ones. This paper first presents the terramechanics of this hybrid electric tracked bulldozer. The driving dynamics for this tracked bulldozer is then analyzed. After that, based on analyzing the working characteristics of the engine, generator, and driving motors, the power train system model and control strategy optimization is established by using MATLAB/Simulink and OPTIMUS software. Simulation is performed under a representative working condition, and the results demonstrate that fuel economy of the HETV can be significantly improved.

  12. Tracking the Penetration of Plasma Reactive Species in Tissue Models.

    Science.gov (United States)

    Szili, Endre J; Hong, Sung-Ha; Oh, Jun-Seok; Gaur, Nishtha; Short, Robert D

    2017-08-23

    Electrically generated cold atmospheric plasma is being intensively researched for novel applications in biology and medicine. Significant attention is being given to reactive oxygen and nitrogen species (RONS), initially generated upon plasma-air interactions, and subsequently delivered to biological systems. Effects of plasma exposure are observed to millimeter depths within tissue. However, the exact nature of the initial plasma-tissue interactions remains unknown, including RONS speciation and delivery depth, or how plasma-derived RONS intervene in biological processes. Herein, we focus on current research using tissue and cell models to learn more about the plasma delivery of RONS into biological environments. We argue that this research is vital in underpinning the knowledge required to realize the full potential of plasma in biology and medicine. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Random vibration analysis of train-bridge under track irregularities and traveling seismic waves using train-slab track-bridge interaction model

    Science.gov (United States)

    Zeng, Zhi-Ping; Zhao, Yan-Gang; Xu, Wen-Tao; Yu, Zhi-Wu; Chen, Ling-Kun; Lou, Ping

    2015-04-01

    The frequent use of bridges in high-speed railway lines greatly increases the probability that trains are running on bridges when earthquakes occur. This paper investigates the random vibrations of a high-speed train traversing a slab track on a continuous girder bridge subjected to track irregularities and traveling seismic waves by the pseudo-excitation method (PEM). To derive the equations of motion of the train-slab track-bridge interaction system, the multibody dynamics and finite element method models are used for the train and the track and bridge, respectively. By assuming track irregularities to be fully coherent random excitations with time lags between different wheels and seismic accelerations to be uniformly modulated, non-stationary random excitations with time lags between different foundations, the random load vectors of the equations of motion are transformed into a series of deterministic pseudo-excitations based on PEM and the wheel-rail contact relationship. A computer code is developed to obtain the time-dependent random responses of the entire system. As a case study, the random vibration characteristics of an ICE-3 high-speed train traversing a seven-span continuous girder bridge simultaneously excited by track irregularities and traveling seismic waves are analyzed. The influence of train speed and seismic wave propagation velocity on the random vibration characteristics of the bridge and train are discussed.

  14. Fuzzy virtual reference model sensorless tracking control for linear induction motors.

    Science.gov (United States)

    Hung, Cheng-Yao; Liu, Peter; Lian, Kuang-Yow

    2013-06-01

    This paper introduces a fuzzy virtual reference model (FVRM) synthesis method for linear induction motor (LIM) speed sensorless tracking control. First, we represent the LIM as a Takagi-Sugeno fuzzy model. Second, we estimate the immeasurable mover speed and secondary flux by a fuzzy observer. Third, to convert the speed tracking control into a stabilization problem, we define the internal desired states for state tracking via an FVRM. Finally, by solving a set of linear matrix inequalities (LMIs), we obtain the observer gains and the control gains where exponential convergence is guaranteed. The contributions of the approach in this paper are threefold: 1) simplified approach--speed tracking problem converted into stabilization problem; 2) omit need of actual reference model--FVRM generates internal desired states; and 3) unification of controller and observer design--control objectives are formulated into an LMI problem where powerful numerical toolboxes solve controller and observer gains. Finally, experiments are carried out to verify the theoretical results and show satisfactory performance both in transient response and robustness.

  15. Quadrotor Trajectory Tracking Based on Quasi-LPV System and Internal Model Control

    Directory of Open Access Journals (Sweden)

    ZeFang He

    2015-01-01

    Full Text Available Internal model control (IMC design method based on quasi-LPV (Linear Parameter Varying system is proposed. In this method, the nonlinear model is firstly transformed to the linear model based on quasi-LPV method; then, the quadrotor nonlinear motion function is transformed to transfer function matrix based on the transformation model from the state space to the transfer function; further, IMC is designed to control the controlled object represented by transfer function matrix and realize quadrotor trajectory tracking. The performance of the controller proposed in this paper is tested by tracking for three reference trajectories with drastic changes. The simulation results indicate that the control method proposed in this paper has stronger robustness to parameters uncertainty and disturbance rejection performance.

  16. Volcano and Ship Tracks Indicate Excessive Aerosol-Induced Cloud Water Increases in a Climate Model

    Science.gov (United States)

    Toll, Velle; Christensen, Matthew; Gassó, Santiago; Bellouin, Nicolas

    2017-12-01

    Aerosol-cloud interaction is the most uncertain mechanism of anthropogenic radiative forcing of Earth's climate, and aerosol-induced cloud water changes are particularly poorly constrained in climate models. By combining satellite retrievals of volcano and ship tracks in stratocumulus clouds, we compile a unique observational data set and confirm that liquid water path (LWP) responses to aerosols are bidirectional, and on average the increases in LWP are closely compensated by the decreases. Moreover, the meteorological parameters controlling the LWP responses are strikingly similar between the volcano and ship tracks. In stark contrast to observations, there are substantial unidirectional increases in LWP in the Hadley Centre climate model, because the model accounts only for the decreased precipitation efficiency and not for the enhanced entrainment drying. If the LWP increases in the model were compensated by the decreases as the observations suggest, its indirect aerosol radiative forcing in stratocumulus regions would decrease by 45%.

  17. Adaptive Correlation Model for Visual Tracking Using Keypoints Matching and Deep Convolutional Feature

    Directory of Open Access Journals (Sweden)

    Yuankun Li

    2018-02-01

    Full Text Available Although correlation filter (CF-based visual tracking algorithms have achieved appealing results, there are still some problems to be solved. When the target object goes through long-term occlusions or scale variation, the correlation model used in existing CF-based algorithms will inevitably learn some non-target information or partial-target information. In order to avoid model contamination and enhance the adaptability of model updating, we introduce the keypoints matching strategy and adjust the model learning rate dynamically according to the matching score. Moreover, the proposed approach extracts convolutional features from a deep convolutional neural network (DCNN to accurately estimate the position and scale of the target. Experimental results demonstrate that the proposed tracker has achieved satisfactory performance in a wide range of challenging tracking scenarios.

  18. Identification and maximum power point tracking of photovoltaic generation by a local neuro-fuzzy model

    OpenAIRE

    Rouzbehi, Kumars; Miranian, Arash; Luna Alloza, Álvaro; Rodríguez Cortés, Pedro

    2012-01-01

    With the rapid proliferation of the DC distribution systems, special attentions are paid to the photovoltaic (PV) generations. This paper addresses the problem of maximum power point tracking (MPPT) for PV systems using a local neuro fuzzy (LNF) network and steepest descent (SD) optimization algorithm. The proposed approach, termed LNF + SD, first identifies a valid an accurate model for the PV system using the LNF network and through measurement data. Then the identified PV model is used for...

  19. Modeling and Robust Trajectory Tracking Control for a Novel Six-Rotor Unmanned Aerial Vehicle

    OpenAIRE

    Yang, Chengshun; Yang, Zhong; Huang, Xiaoning; Li, Shaobin; Zhang, Qiang

    2013-01-01

    Modeling and trajectory tracking control of a novel six-rotor unmanned aerial vehicle (UAV) is concerned to solve problems such as smaller payload capacity and lack of both hardware redundancy and anticrosswind capability for quad-rotor. The mathematical modeling for the six-rotor UAV is developed on the basis of the Newton-Euler formalism, and a second-order sliding-mode disturbance observer (SOSMDO) is proposed to reconstruct the disturbances of the rotational dynamics. In consideration of ...

  20. Development of internal models and predictive abilities for visual tracking during childhood

    OpenAIRE

    Ego, Caroline; Yüksel, Demet; Orban de Xivry, Jean-Jacques; Lefèvre, Philippe

    2016-01-01

    The prediction of the consequences of our own actions through internal models is an essential component of motor control. Previous studies showed improvement of anticipatory behaviors with age for grasping, drawing, and postural control. Since these actions require visual and proprioceptive feedback, these improvements might reflect both the development of internal models and the feedback control. In contrast, visual tracking of a temporarily invisible target gives specific markers of predict...

  1. Amorphous Phases on the Surface of Mars

    Science.gov (United States)

    Rampe, E. B.; Morris, R. V.; Ruff, S. W.; Horgan, B.; Dehouck, E.; Achilles, C. N.; Ming, D. W.; Bish, D. L.; Chipera, S. J.

    2014-01-01

    Both primary (volcanic/impact glasses) and secondary (opal/silica, allophane, hisingerite, npOx, S-bearing) amorphous phases appear to be major components of martian surface materials based on orbital and in-situ measurements. A key observation is that whereas regional/global scale amorphous components include altered glass and npOx, local scale amorphous phases include hydrated silica/opal. This suggests widespread alteration at low water-to-rock ratios, perhaps due to snow/ice melt with variable pH, and localized alteration at high water-to-rock ratios. Orbital and in-situ measurements of the regional/global amorphous component on Mars suggests that it is made up of at least three phases: npOx, amorphous silicate (likely altered glass), and an amorphous S-bearing phase. Fundamental questions regarding the composition and the formation of the regional/global amorphous component(s) still remain: Do the phases form locally or have they been homogenized through aeolian activity and derived from the global dust? Is the parent glass volcanic, impact, or both? Are the phases separate or intimately mixed (e.g., as in palagonite)? When did the amorphous phases form? To address the question of source (local and/or global), we need to look for variations in the different phases within the amorphous component through continued modeling of the chemical composition of the amorphous phases in samples from Gale using CheMin and APXS data. If we find variations (e.g., a lack of or enrichment in amorphous silicate in some samples), this may imply a local source for some phases. Furthermore, the chemical composition of the weathering products may give insight into the formation mechanisms of the parent glass (e.g., impact glasses contain higher Al and lower Si [30], so we might expect allophane as a weathering product of impact glass). To address the question of whether these phases are separate or intimately mixed, we need to do laboratory studies of naturally altered samples made

  2. Multi-modal imaging, model-based tracking, and mixed reality visualisation for orthopaedic surgery.

    Science.gov (United States)

    Lee, Sing Chun; Fuerst, Bernhard; Tateno, Keisuke; Johnson, Alex; Fotouhi, Javad; Osgood, Greg; Tombari, Federico; Navab, Nassir

    2017-10-01

    Orthopaedic surgeons are still following the decades old workflow of using dozens of two-dimensional fluoroscopic images to drill through complex 3D structures, e.g. pelvis. This Letter presents a mixed reality support system, which incorporates multi-modal data fusion and model-based surgical tool tracking for creating a mixed reality environment supporting screw placement in orthopaedic surgery. A red-green-blue-depth camera is rigidly attached to a mobile C-arm and is calibrated to the cone-beam computed tomography (CBCT) imaging space via iterative closest point algorithm. This allows real-time automatic fusion of reconstructed surface and/or 3D point clouds and synthetic fluoroscopic images obtained through CBCT imaging. An adapted 3D model-based tracking algorithm with automatic tool segmentation allows for tracking of the surgical tools occluded by hand. This proposed interactive 3D mixed reality environment provides an intuitive understanding of the surgical site and supports surgeons in quickly localising the entry point and orienting the surgical tool during screw placement. The authors validate the augmentation by measuring target registration error and also evaluate the tracking accuracy in the presence of partial occlusion.

  3. A model predictive speed tracking control approach for autonomous ground vehicles

    Science.gov (United States)

    Zhu, Min; Chen, Huiyan; Xiong, Guangming

    2017-03-01

    This paper presents a novel speed tracking control approach based on a model predictive control (MPC) framework for autonomous ground vehicles. A switching algorithm without calibration is proposed to determine the drive or brake control. Combined with a simple inverse longitudinal vehicle model and adaptive regulation of MPC, this algorithm can make use of the engine brake torque for various driving conditions and avoid high frequency oscillations automatically. A simplified quadratic program (QP) solving algorithm is used to reduce the computational time, and the approach has been applied in a 16-bit microcontroller. The performance of the proposed approach is evaluated via simulations and vehicle tests, which were carried out in a range of speed-profile tracking tasks. With a well-designed system structure, high-precision speed control is achieved. The system can robustly model uncertainty and external disturbances, and yields a faster response with less overshoot than a PI controller.

  4. Track etching model for normal incident heavy ion recording in isotropic dielectric detectors

    International Nuclear Information System (INIS)

    Membrey, F.; Chambaudet, A.; Fromm, M.; Saouli, R.

    1990-01-01

    Heavy ion recording in dielectric isotropic detectors has a wide range of applications in such areas as uranium cartography, neutron activation and fission track dating using the external detector method (EDM). It is important to have a good understanding of etch pit evolution during chemical etching. The conical model, which is very often used, is based on a constant track etching velocity (VT). Numerous experiments have shown, however, that VT varies along the damage trail. In this paper, we propose a computer-generated model which simulates the etching process for normal incident ions. The analytical form of VT must be chosen in order to describe as precisely as possible the relationship between etching time (residual range) and the VT value. The conical model only provides a primary approximation which is generally insufficient, especially when performing cartography. (author)

  5. Eye-tracking measurements and their link to a normative model of monitoring behaviour.

    Science.gov (United States)

    Hasse, Catrin; Bruder, Carmen

    2015-01-01

    Increasing automation necessitates operators monitoring appropriately (OMA) and raises the question of how to identify them in future selections. A normative model was developed providing criteria for the identification of OMA. According to this model, the monitoring process comprises distinct monitoring phases (orientation, anticipation, detection and recheck) in which attention should be focused on relevant areas. The current study tests the normative model on the basis of eye tracking. The eye-tracking data revealed increased concentration on relevant areas during the orientation and anticipation phase in comparison to the other phases. For the assessment of monitoring behaviour in the context of personnel selection, this implies that the anticipation and orientation phases should be considered separately as they appear to be more important in the context of monitoring than the other phases. A normative model was developed for the assessment of monitoring behaviour. Using the eye-tracking method, this model was tested with applicants for an Air Traffic Controller training programme. The results are relevant for the future selection of human operators, who will have to monitor highly automated systems.

  6. Lipid-Based Formulations Can Enable the Model Poorly Water-Soluble Weakly Basic Drug Cinnarizine to Precipitate in an Amorphous-Salt Form during in Vitro Digestion

    DEFF Research Database (Denmark)

    Khan, Jamal; Rades, Thomas; Boyd, Ben J

    2016-01-01

    weakly basic drug and was dissolved in a medium-chain (MC) LBF, which was subject to in vitro lipolysis experiments at various pH levels above and below the reported pKa value of cinnarizine (7.47). The solid-state form of the precipitated drug was analyzed using X-ray diffraction (XRD), Fourier......The tendency for poorly water-soluble weakly basic drugs to precipitate in a noncrystalline form during the in vitro digestion of lipid-based formulations (LBFs) was linked to an ionic interaction between drug and fatty acid molecules produced upon lipid digestion. Cinnarizine was chosen as a model...... from the starting free base crystalline material to the hydrochloride salt, thus supporting the case that ionic interactions between weak bases and fatty acid molecules during digestion are responsible for producing amorphous-salts upon precipitation. The conclusion has wide implications...

  7. Multiple player tracking in sports video: a dual-mode two-way bayesian inference approach with progressive observation modeling.

    Science.gov (United States)

    Xing, Junliang; Ai, Haizhou; Liu, Liwei; Lao, Shihong

    2011-06-01

    Multiple object tracking (MOT) is a very challenging task yet of fundamental importance for many practical applications. In this paper, we focus on the problem of tracking multiple players in sports video which is even more difficult due to the abrupt movements of players and their complex interactions. To handle the difficulties in this problem, we present a new MOT algorithm which contributes both in the observation modeling level and in the tracking strategy level. For the observation modeling, we develop a progressive observation modeling process that is able to provide strong tracking observations and greatly facilitate the tracking task. For the tracking strategy, we propose a dual-mode two-way Bayesian inference approach which dynamically switches between an offline general model and an online dedicated model to deal with single isolated object tracking and multiple occluded object tracking integrally by forward filtering and backward smoothing. Extensive experiments on different kinds of sports videos, including football, basketball, as well as hockey, demonstrate the effectiveness and efficiency of the proposed method.

  8. Structural amorphous steels

    International Nuclear Information System (INIS)

    Lu, Z.P.; Liu, C.T.; Porter, W.D.; Thompson, J.R.

    2004-01-01

    Recent advancement in bulk metallic glasses, whose properties are usually superior to their crystalline counterparts, has stimulated great interest in fabricating bulk amorphous steels. While a great deal of effort has been devoted to this field, the fabrication of structural amorphous steels with large cross sections has remained an alchemist's dream because of the limited glass-forming ability (GFA) of these materials. Here we report the discovery of structural amorphous steels that can be cast into glasses with large cross-section sizes using conventional drop-casting methods. These new steels showed interesting physical, magnetic, and mechanical properties, along with high thermal stability. The underlying mechanisms for the superior GFA of these materials are discussed

  9. Enhanced index tracking modeling in portfolio optimization with mixed-integer programming z approach

    Science.gov (United States)

    Siew, Lam Weng; Jaaman, Saiful Hafizah Hj.; Ismail, Hamizun bin

    2014-09-01

    Enhanced index tracking is a popular form of portfolio management in stock market investment. Enhanced index tracking aims to construct an optimal portfolio to generate excess return over the return achieved by the stock market index without purchasing all of the stocks that make up the index. The objective of this paper is to construct an optimal portfolio using mixed-integer programming model which adopts regression approach in order to generate higher portfolio mean return than stock market index return. In this study, the data consists of 24 component stocks in Malaysia market index which is FTSE Bursa Malaysia Kuala Lumpur Composite Index from January 2010 until December 2012. The results of this study show that the optimal portfolio of mixed-integer programming model is able to generate higher mean return than FTSE Bursa Malaysia Kuala Lumpur Composite Index return with only selecting 30% out of the total stock market index components.

  10. Rotational Kinematics Model Based Adaptive Particle Filter for Robust Human Tracking in Thermal Omnidirectional Vision

    Directory of Open Access Journals (Sweden)

    Yazhe Tang

    2015-01-01

    Full Text Available This paper presents a novel surveillance system named thermal omnidirectional vision (TOV system which can work in total darkness with a wild field of view. Different to the conventional thermal vision sensor, the proposed vision system exhibits serious nonlinear distortion due to the effect of the quadratic mirror. To effectively model the inherent distortion of omnidirectional vision, an equivalent sphere projection is employed to adaptively calculate parameterized distorted neighborhood of an object in the image plane. With the equivalent projection based adaptive neighborhood calculation, a distortion-invariant gradient coding feature is proposed for thermal catadioptric vision. For robust tracking purpose, a rotational kinematic modeled adaptive particle filter is proposed based on the characteristic of omnidirectional vision, which can handle multiple movements effectively, including the rapid motions. Finally, the experiments are given to verify the performance of the proposed algorithm for human tracking in TOV system.

  11. Tracking Maneuvering Group Target with Extension Predicted and Best Model Augmentation Method Adapted

    Directory of Open Access Journals (Sweden)

    Linhai Gan

    2017-01-01

    Full Text Available The random matrix (RM method is widely applied for group target tracking. The assumption that the group extension keeps invariant in conventional RM method is not yet valid, as the orientation of the group varies rapidly while it is maneuvering; thus, a new approach with group extension predicted is derived here. To match the group maneuvering, a best model augmentation (BMA method is introduced. The existing BMA method uses a fixed basic model set, which may lead to a poor performance when it could not ensure basic coverage of true motion modes. Here, a maneuvering group target tracking algorithm is proposed, where the group extension prediction and the BMA adaption are exploited. The performance of the proposed algorithm will be illustrated by simulation.

  12. Model estimation and identification of manual controller objectives in complex tracking tasks

    Science.gov (United States)

    Schmidt, D. K.; Yuan, P. J.

    1984-01-01

    A methodology is presented for estimating the parameters in an optimal control structural model of the manual controller from experimental data on complex, multiinput/multioutput tracking tasks. Special attention is devoted to estimating the appropriate objective function for the task, as this is considered key in understanding the objectives and strategy of the manual controller. The technique is applied to data from single input/single output as well as multi input/multi outpuut experiments, and results discussed.

  13. CT patterns of pleuro-pulmonary damage caused by inhalation of pumice as a model of pneumoconiosis from non-fibrous amorphous silicates.

    Science.gov (United States)

    Costa, Chiara; Ascenti, Giorgio; Scribano, Emanuele; D'Angelo, Tommaso; Gaeta, Michele; Fenga, Concettina; Blandino, Alfredo; Mazziotti, Silvio

    2016-01-01

    The aim of this article is to correlate the radiological features of pleuro-pulmonary damage caused by inhalation of pumice (an extrusive volcanic rock classified as a non-fibrous, amorphous, complex silicate) with exposure conditions. 36 subjects employed in the pumice quarries were evaluated for annual follow-up in a preventive medical surveillance program including spirometry, chest CT lasting from 1999 to 2014. They were only male subjects, mean age 56.92 ± 16.45 years. Subjects had worked in the quarries for an average of 25.03 ± 9.39 years. Domestic or occupational exposure to asbestos or other mineral dusts other than pumice was excluded. Subjects were also classified as smokers, former smokers and nonsmokers. Among the 36 workers examined, we identified four CT patterns which resulted to be dependent on exposure duration and intensity, FVC, FEV1 and FEF25-75, but not on cigarette smoking. The most common symptoms reported by clinical examination were dyspnoea, cough and asthenia. In no case it was proven an evolution of CT findings during follow-up for 10 years. Liparitosis, caused by pumice inhalation, can be considered a representative example of pneumoconiosis derived by amorphous silica compounds, which are extremely widespread for industrial manufacturing as well as for applicative uses, such as nano-materials. Moreover, being pumice free of quartz contamination, it can represent a disease model for exposure to pure non-fibrous silicates.

  14. Plant Cell Population Tracking in a Honeycomb Structure Using an IMM Filter Based 3D Local Graph Matching Model.

    Science.gov (United States)

    Liu, Min; He, Yue; Qian, Weili; Wei, Yangliu; Liu, Xiaoyan

    2017-10-06

    Developing algorithms for plant cell population tracking is very critical for the modeling of plant cell growth pattern and gene expression dynamics. The tracking of plant cells in microscopic image stacks is very challenging for several reasons: (1) plant cells are densely packed in a specific honeycomb structure; (2) they are frequently dividing; (3) they are imaged in different layers within 3D image stacks. Based on an existing 2D local graph matching algorithm, this paper focuses on building a 3D plant cell matching model, by exploiting the cells' 3D spatiotemporal context. Furthermore, the Interacting Multi-Model filter (IMM) is combined with the 3D local graph matching model to track the plant cell population simultaneously. Because our tracking algorithm does not require the identification of "tracking seeds", the tracking stability and efficiency are greatly enhanced. Last, the plant cell lineages are achieved by associating the cell tracklets, using a maximum-a-posteriori (MAP) method. Compared with the 2D matching method, the experimental results on multiple datasets show that our proposed approach does not only greatly improve the tracking accuracy by 18%, but also successfully tracks the plant cells located at the high curvature primordial region, which is not addressed in previous work.

  15. An Analysis Technique/Automated Tool for Comparing and Tracking Analysis Modes of Different Finite Element Models

    Science.gov (United States)

    Towner, Robert L.; Band, Jonathan L.

    2012-01-01

    An analysis technique was developed to compare and track mode shapes for different Finite Element Models. The technique may be applied to a variety of structural dynamics analyses, including model reduction validation (comparing unreduced and reduced models), mode tracking for various parametric analyses (e.g., launch vehicle model dispersion analysis to identify sensitivities to modal gain for Guidance, Navigation, and Control), comparing models of different mesh fidelity (e.g., a coarse model for a preliminary analysis compared to a higher-fidelity model for a detailed analysis) and mode tracking for a structure with properties that change over time (e.g., a launch vehicle from liftoff through end-of-burn, with propellant being expended during the flight). Mode shapes for different models are compared and tracked using several numerical indicators, including traditional Cross-Orthogonality and Modal Assurance Criteria approaches, as well as numerical indicators obtained by comparing modal strain energy and kinetic energy distributions. This analysis technique has been used to reliably identify correlated mode shapes for complex Finite Element Models that would otherwise be difficult to compare using traditional techniques. This improved approach also utilizes an adaptive mode tracking algorithm that allows for automated tracking when working with complex models and/or comparing a large group of models.

  16. Onboard Robust Visual Tracking for UAVs Using a Reliable Global-Local Object Model.

    Science.gov (United States)

    Fu, Changhong; Duan, Ran; Kircali, Dogan; Kayacan, Erdal

    2016-08-31

    In this paper, we present a novel onboard robust visual algorithm for long-term arbitrary 2D and 3D object tracking using a reliable global-local object model for unmanned aerial vehicle (UAV) applications, e.g., autonomous tracking and chasing a moving target. The first main approach in this novel algorithm is the use of a global matching and local tracking approach. In other words, the algorithm initially finds feature correspondences in a way that an improved binary descriptor is developed for global feature matching and an iterative Lucas-Kanade optical flow algorithm is employed for local feature tracking. The second main module is the use of an efficient local geometric filter (LGF), which handles outlier feature correspondences based on a new forward-backward pairwise dissimilarity measure, thereby maintaining pairwise geometric consistency. In the proposed LGF module, a hierarchical agglomerative clustering, i.e., bottom-up aggregation, is applied using an effective single-link method. The third proposed module is a heuristic local outlier factor (to the best of our knowledge, it is utilized for the first time to deal with outlier features in a visual tracking application), which further maximizes the representation of the target object in which we formulate outlier feature detection as a binary classification problem with the output features of the LGF module. Extensive UAV flight experiments show that the proposed visual tracker achieves real-time frame rates of more than thirty-five frames per second on an i7 processor with 640 × 512 image resolution and outperforms the most popular state-of-the-art trackers favorably in terms of robustness, efficiency and accuracy.

  17. Radar tracking with an interacting multiple model and probabilistic data association filter for civil aviation applications.

    Science.gov (United States)

    Jan, Shau-Shiun; Kao, Yu-Chun

    2013-05-17

    The current trend of the civil aviation technology is to modernize the legacy air traffic control (ATC) system that is mainly supported by many ground based navigation aids to be the new air traffic management (ATM) system that is enabled by global positioning system (GPS) technology. Due to the low receiving power of GPS signal, it is a major concern to aviation authorities that the operation of the ATM system might experience service interruption when the GPS signal is jammed by either intentional or unintentional radio-frequency interference. To maintain the normal operation of the ATM system during the period of GPS outage, the use of the current radar system is proposed in this paper. However, the tracking performance of the current radar system could not meet the required performance of the ATM system, and an enhanced tracking algorithm, the interacting multiple model and probabilistic data association filter (IMMPDAF), is therefore developed to support the navigation and surveillance services of the ATM system. The conventional radar tracking algorithm, the nearest neighbor Kalman filter (NNKF), is used as the baseline to evaluate the proposed radar tracking algorithm, and the real flight data is used to validate the IMMPDAF algorithm. As shown in the results, the proposed IMMPDAF algorithm could enhance the tracking performance of the current aviation radar system and meets the required performance of the new ATM system. Thus, the current radar system with the IMMPDAF algorithm could be used as an alternative system to continue aviation navigation and surveillance services of the ATM system during GPS outage periods.

  18. Radar Tracking with an Interacting Multiple Model and Probabilistic Data Association Filter for Civil Aviation Applications

    Directory of Open Access Journals (Sweden)

    Shau-Shiun Jan

    2013-05-01

    Full Text Available The current trend of the civil aviation technology is to modernize the legacy air traffic control (ATC system that is mainly supported by many ground based navigation aids to be the new air traffic management (ATM system that is enabled by global positioning system (GPS technology. Due to the low receiving power of GPS signal, it is a major concern to aviation authorities that the operation of the ATM system might experience service interruption when the GPS signal is jammed by either intentional or unintentional radio-frequency interference. To maintain the normal operation of the ATM system during the period of GPS outage, the use of the current radar system is proposed in this paper. However, the tracking performance of the current radar system could not meet the required performance of the ATM system, and an enhanced tracking algorithm, the interacting multiple model and probabilistic data association filter (IMMPDAF, is therefore developed to support the navigation and surveillance services of the ATM system. The conventional radar tracking algorithm, the nearest neighbor Kalman filter (NNKF, is used as the baseline to evaluate the proposed radar tracking algorithm, and the real flight data is used to validate the IMMPDAF algorithm. As shown in the results, the proposed IMMPDAF algorithm could enhance the tracking performance of the current aviation radar system and meets the required performance of the new ATM system. Thus, the current radar system with the IMMPDAF algorithm could be used as an alternative system to continue aviation navigation and surveillance services of the ATM system during GPS outage periods.

  19. ENSO Effect on East Asian Tropical Cyclone Landfall via Changes in Tracks and Genesis in a Statistical Model

    Science.gov (United States)

    Yonekura, Emmi; Hall, Timothy M.

    2014-01-01

    Improvements on a statistical tropical cyclone (TC) track model in the western North Pacific Ocean are described. The goal of the model is to study the effect of El Nino-Southern Oscillation (ENSO) on East Asian TC landfall. The model is based on the International Best-Track Archive for Climate Stewardship (IBTrACS) database of TC observations for 1945-2007 and employs local regression of TC formation rates and track increments on the Nino-3.4 index and seasonally varying climate parameters. The main improvements are the inclusion of ENSO dependence in the track propagation and accounting for seasonality in both genesis and tracks. A comparison of simulations of the 1945-2007 period with observations concludes that the model updates improve the skill of this model in simulating TCs. Changes in TC genesis and tracks are analyzed separately and cumulatively in simulations of stationary extreme ENSO states. ENSO effects on regional (100-km scale) landfall are attributed to changes in genesis and tracks. The effect of ENSO on genesis is predominantly a shift in genesis location from the southeast in El Nino years to the northwest in La Nina years, resulting in higher landfall rates for the East Asian coast during La Nina. The effect of ENSO on track propagation varies seasonally and spatially. In the peak activity season (July-October), there are significant changes in mean tracks with ENSO. Landfall-rate changes from genesis- and track-ENSO effects in the Philippines cancel out, while coastal segments of Vietnam, China, the Korean Peninsula, and Japan show enhanced La Nina-year increases.

  20. Feature Classification for Robust Shape-Based Collaborative Tracking and Model Updating

    Directory of Open Access Journals (Sweden)

    C. S. Regazzoni

    2008-09-01

    Full Text Available A new collaborative tracking approach is introduced which takes advantage of classified features. The core of this tracker is a single tracker that is able to detect occlusions and classify features contributing in localizing the object. Features are classified in four classes: good, suspicious, malicious, and neutral. Good features are estimated to be parts of the object with a high degree of confidence. Suspicious ones have a lower, yet significantly high, degree of confidence to be a part of the object. Malicious features are estimated to be generated by clutter, while neutral features are characterized with not a sufficient level of uncertainty to be assigned to the tracked object. When there is no occlusion, the single tracker acts alone, and the feature classification module helps it to overcome distracters such as still objects or little clutter in the scene. When more than one desired moving objects bounding boxes are close enough, the collaborative tracker is activated and it exploits the advantages of the classified features to localize each object precisely as well as updating the objects shape models more precisely by assigning again the classified features to the objects. The experimental results show successful tracking compared with the collaborative tracker that does not use the classified features. Moreover, more precise updated object shape models will be shown.

  1. An Efficient Implementation of Track-Oriented Multiple Hypothesis Tracker Using Graphical Model Approaches

    Directory of Open Access Journals (Sweden)

    Jinping Sun

    2017-01-01

    Full Text Available The multiple hypothesis tracker (MHT is currently the preferred method for addressing data association problem in multitarget tracking (MTT application. MHT seeks the most likely global hypothesis by enumerating all possible associations over time, which is equal to calculating maximum a posteriori (MAP estimate over the report data. Despite being a well-studied method, MHT remains challenging mostly because of the computational complexity of data association. In this paper, we describe an efficient method for solving the data association problem using graphical model approaches. The proposed method uses the graph representation to model the global hypothesis formation and subsequently applies an efficient message passing algorithm to obtain the MAP solution. Specifically, the graph representation of data association problem is formulated as a maximum weight independent set problem (MWISP, which translates the best global hypothesis formation into finding the maximum weight independent set on the graph. Then, a max-product belief propagation (MPBP inference algorithm is applied to seek the most likely global hypotheses with the purpose of avoiding a brute force hypothesis enumeration procedure. The simulation results show that the proposed MPBP-MHT method can achieve better tracking performance than other algorithms in challenging tracking situations.

  2. User guide for MODPATH version 6 - A particle-tracking model for MODFLOW

    Science.gov (United States)

    Pollock, David W.

    2012-01-01

    MODPATH is a particle-tracking post-processing model that computes three-dimensional flow paths using output from groundwater flow simulations based on MODFLOW, the U.S. Geological Survey (USGS) finite-difference groundwater flow model. This report documents MODPATH version 6. Previous versions were documented in USGS Open-File Reports 89-381 and 94-464. The program uses a semianalytical particle-tracking scheme that allows an analytical expression of a particle's flow path to be obtained within each finite-difference grid cell. A particle's path is computed by tracking the particle from one cell to the next until it reaches a boundary, an internal sink/source, or satisfies another termination criterion. Data input to MODPATH consists of a combination of MODFLOW input data files, MODFLOW head and flow output files, and other input files specific to MODPATH. Output from MODPATH consists of several output files, including a number of particle coordinate output files intended to serve as input data for other programs that process, analyze, and display the results in various ways. MODPATH is written in FORTRAN and can be compiled by any FORTRAN compiler that fully supports FORTRAN-2003 or by most commercially available FORTRAN-95 compilers that support the major FORTRAN-2003 language extensions.

  3. Real Time Optima Tracking Using Harvesting Models of the Genetic Algorithm

    Science.gov (United States)

    Baskaran, Subbiah; Noever, D.

    1999-01-01

    Tracking optima in real time propulsion control, particularly for non-stationary optimization problems is a challenging task. Several approaches have been put forward for such a study including the numerical method called the genetic algorithm. In brief, this approach is built upon Darwinian-style competition between numerical alternatives displayed in the form of binary strings, or by analogy to 'pseudogenes'. Breeding of improved solution is an often cited parallel to natural selection in.evolutionary or soft computing. In this report we present our results of applying a novel model of a genetic algorithm for tracking optima in propulsion engineering and in real time control. We specialize the algorithm to mission profiling and planning optimizations, both to select reduced propulsion needs through trajectory planning and to explore time or fuel conservation strategies.

  4. Output tracking and synchronization of chaotic Chua's circuit with disturbances via model predictive regulator

    International Nuclear Information System (INIS)

    Zhang Tiejun; Feng Gang

    2009-01-01

    In this paper, we consider the output tracking and synchronization problem for a piecewise linear chaotic Chua's circuit, which is expected to follow the reference signal generated by another autonomous chaotic Chua's circuit. A novel model predictive regulator is proposed to guarantee the chaos synchronization in the presence of external disturbance. Moreover with this regulator, the optimal transient tracking performance for synchronization is ensured even when the piecewise autonomous and controlled Chua's circuits switch asynchronously. The proposed approach is highly efficient in the sense that the regulation conditions can be satisfied by solving a set of linear matrix inequalities and several Sylvester equations instead of many partial differential regulator equations in the well-known nonlinear output regulation theory.

  5. A semi-analytical beam model for the vibration of railway tracks

    Science.gov (United States)

    Kostovasilis, D.; Thompson, D. J.; Hussein, M. F. M.

    2017-04-01

    The high frequency dynamic behaviour of railway tracks, in both vertical and lateral directions, strongly affects the generation of rolling noise as well as other phenomena such as rail corrugation. An improved semi-analytical model of a beam on an elastic foundation is introduced that accounts for the coupling of the vertical and lateral vibration. The model includes the effects of cross-section asymmetry, shear deformation, rotational inertia and restrained warping. Consideration is given to the fact that the loads at the rail head, as well as those exerted by the railpads at the rail foot, may not act through the centroid of the section. The response is evaluated for a harmonic load and the solution is obtained in the wavenumber domain. Results are presented as dispersion curves for free and supported rails and are validated with the aid of a Finite Element (FE) and a waveguide finite element (WFE) model. Closed form expressions are derived for the forced response, and validated against the WFE model. Track mobilities and decay rates are presented to assess the potential implications for rolling noise and the influence of the various sources of vertical-lateral coupling. Comparison is also made with measured data. Overall, the model presented performs very well, especially for the lateral vibration, although it does not contain the high frequency cross-section deformation modes. The most significant effects on the response are shown to be the inclusion of torsion and foundation eccentricity, which mainly affect the lateral response.

  6. Species distribution models for a migratory bird based on citizen science and satellite tracking data

    Directory of Open Access Journals (Sweden)

    Christopher L. Coxen

    2017-07-01

    Full Text Available Species distribution models can provide critical baseline distribution information for the conservation of poorly understood species. Here, we compared the performance of band-tailed pigeon (Patagioenas fasciata species distribution models created using Maxent and derived from two separate presence-only occurrence data sources in New Mexico: 1 satellite tracked birds and 2 observations reported in eBird basic data set. Both models had good accuracy (test AUC > 0.8 and True Skill Statistic > 0.4, and high overlap between suitability scores (I statistic 0.786 and suitable habitat patches (relative rank 0.639. Our results suggest that, at the state-wide level, eBird occurrence data can effectively model similar species distributions as satellite tracking data. Climate change models for the band-tailed pigeon predict a 35% loss in area of suitable climate by 2070 if CO2 emissions drop to 1990 levels by 2100, and a 45% loss by 2070 if we continue current CO2 emission levels through the end of the century. These numbers may be conservative given the predicted increase in drought, wildfire, and forest pest impacts to the coniferous forests the species inhabits in New Mexico. The northern portion of the species’ range in New Mexico is predicted to be the most viable through time.

  7. Species distribution models for a migratory bird based on citizen science and satellite tracking data

    Science.gov (United States)

    Coxen, Christopher L.; Frey, Jennifer K.; Carleton, Scott A.; Collins, Daniel P.

    2017-01-01

    Species distribution models can provide critical baseline distribution information for the conservation of poorly understood species. Here, we compared the performance of band-tailed pigeon (Patagioenas fasciata) species distribution models created using Maxent and derived from two separate presence-only occurrence data sources in New Mexico: 1) satellite tracked birds and 2) observations reported in eBird basic data set. Both models had good accuracy (test AUC > 0.8 and True Skill Statistic > 0.4), and high overlap between suitability scores (I statistic 0.786) and suitable habitat patches (relative rank 0.639). Our results suggest that, at the state-wide level, eBird occurrence data can effectively model similar species distributions as satellite tracking data. Climate change models for the band-tailed pigeon predict a 35% loss in area of suitable climate by 2070 if CO2 emissions drop to 1990 levels by 2100, and a 45% loss by 2070 if we continue current CO2 emission levels through the end of the century. These numbers may be conservative given the predicted increase in drought, wildfire, and forest pest impacts to the coniferous forests the species inhabits in New Mexico. The northern portion of the species’ range in New Mexico is predicted to be the most viable through time.

  8. MODELING OF RAILWAY TRACK OPERATION AS A SYSTEM OF QUASI-ELASTIC ORTHOTROPIC LAYERS

    Directory of Open Access Journals (Sweden)

    Sychev Vyacheslav Petrovich

    2016-03-01

    Full Text Available In this paper the authors give a solution to the problem of the impact of a rolling stock on the rail track on the basis of modeling a railway track as a multi-layered space, introducing each of the layers is a quasi-elastic orthotropic layer with cylindrical anisotropy in the polar coordinate system. The article describes wave equations, taking into account the rotational inertia of cross sectional and transverse shear strains. From the point of view of classical structural mechanics train path can be represented as a multilayer system comprising separate layers with different stiffness, lying on the foundation being the elastic-isotropic space. Winkler model provides that the basis is linearly deformable space, there are loads influencing its surface. These loads are transferred through a layered deformable half-space. This representation is used in this study as an initial approximation. For more accurate results of the deformation of a railway track because of rolling dynamic loads it is proposed to present a railway track in the form of a layered structure, where each element (assembled rails and sleepers, ballast section, the soil in the embankment, basement soils is modeled as a planar quasi-elastic orthotropic layer with cylindrical anisotropy. The equations describing the dynamic behaviour of flat element in a polar coordinate system are hyperbolic in nature and take into account the rotational inertia of the cross sectional and the transverse shear strains. This allows identifying the impact on the final characteristics of the blade wave effects, and oscillatory processes. In order to determine the unknown functions included in the constitutive equations it is proposed to use decomposition in power series in spatial coordinate and time. In order to determine the coefficients of ray series for the required functions, it is necessary to differentiate the defining wave equations k times on time, to take their difference on the different

  9. Phase transformations of amorphous semiconductor alloys under high pressures

    CERN Document Server

    Antonov, V E; Fedotov, V K; Harkunov, A I; Ponyatovsky, E G

    2002-01-01

    The paper reviews the results of experimental studies and thermodynamical modelling of metastable T-P diagrams of initially amorphous GaSb-Ge and Zn-Sb alloys which provide a new insight into the problem of pressure-induced amorphization.

  10. Fast surface crystallization of amorphous griseofulvin below T g.

    Science.gov (United States)

    Zhu, Lei; Jona, Janan; Nagapudi, Karthik; Wu, Tian

    2010-08-01

    To study crystal growth rates of amorphous griseofulvin (GSF) below its glass transition temperature (T (g)) and the effect of surface crystallization on the overall crystallization kinetics of amorphous GSF. Amorphous GSF was generated by melt quenching. Surface and bulk crystal growth rates were determined using polarized light microscope. X-ray powder diffraction (XRPD) and Raman microscopy were used to identify the polymorph of the crystals. Crystallization kinetics of amorphous GSF powder stored at 40 degrees C (T (g)-48 degrees C) and room temperature (T (g)-66 degrees C) was monitored using XRPD. Crystal growth at the surface of amorphous GSF is 10- to 100-fold faster than that in the bulk. The surface crystal growth can be suppressed by an ultrathin gold coating. Below T (g), the crystallization of amorphous GSF powder was biphasic with a rapid initial crystallization stage dominated by the surface crystallization and a slow or suspended late stage controlled by the bulk crystallization. GSF exhibits the fastest surface crystallization kinetics among the known amorphous pharmaceutical solids. Well below T (g), surface crystallization dominated the overall crystallization kinetics of amorphous GSF powder. Thus, surface crystallization should be distinguished from bulk crystallization in studying, modeling and controlling the crystallization of amorphous solids.

  11. Role of sensory information in updating internal models of the effector during arm tracking.

    Science.gov (United States)

    Vercher, Jean-Louis; Sarès, Frédéric; Blouin, Jean; Bourdin, Christophe; Gauthier, Gabriel

    2003-01-01

    This chapter is divided into three main parts. Firstly, on the basis of the literature, we will shortly discuss how the recent introduction of the concept of internal models by Daniel Wolpert and Mitsuo Kawato contributes to a better understanding of what is motor learning and what is motor adaptation. Then, we will present a model of eye-hand co-ordination during self-moved target tracking, which we used as a way to specifically address these topics. Finally, we will show some evidence about the use of proprioceptive information for updating the internal models, in the context of eye-hand co-ordination. Motor and afferent information appears to contribute to the parametric adjustment (adaptation) between arm motor command and visual information about arm motion. The study reported here was aimed at assessing the contribution of arm proprioception in building (learning) and updating (adaptation) these representations. The subjects (including a deafferented subject) had to make back and forth movements with their forearm in the horizontal plane, over learned amplitude and at constant frequency, and to track an arm-driven target with their eyes. The dynamical conditions of arm movement were altered (unexpectedly or systematically) during the movement by changing the mechanical properties of the manipulandum. The results showed a significant change of the latency and the gain of the smooth pursuit system, before and after the perturbation for the control subjects, but not for the deafferented subject. Moreover, in control subjects, vibrations of the arm muscles prevented adaptation to the mechanical perturbation. These results suggest that in a self-moved target tracking task, the arm motor system shares with the smooth pursuit system an internal representation of the arm dynamical properties, and that arm proprioception is necessary to build this internal model. As suggested by Ghez et al. (1990) (Cold Spring Harbor Symp. Quant. Biol., 55: 837-8471), proprioception

  12. Comparison of 2D and 3D modeled tumor motion estimation/prediction for dynamic tumor tracking during arc radiotherapy

    Science.gov (United States)

    Liu, Wu; Ma, Xiangyu; Yan, Huagang; Chen, Zhe; Nath, Ravinder; Li, Haiyun

    2017-05-01

    Many real-time imaging techniques have been developed to localize a target in 3D space or in a 2D beam’s eye view (BEV) plane for intrafraction motion tracking in radiation therapy. With tracking system latency, the 3D-modeled method is expected to be more accurate even in terms of 2D BEV tracking error. No quantitative analysis, however, has been reported. In this study, we simulated co-planar arc deliveries using respiratory motion data acquired from 42 patients to quantitatively compare the accuracy between 2D BEV and 3D-modeled tracking in arc therapy and to determine whether 3D information is needed for motion tracking. We used our previously developed low kV dose adaptive MV-kV imaging and motion compensation framework as a representative of 3D-modeled methods. It optimizes the balance between additional kV imaging dose and 3D tracking accuracy and solves the MLC blockage issue. With simulated Gaussian marker detection errors (zero mean and 0.39 mm standard deviation) and ~155/310/460 ms tracking system latencies, the mean percentage of time that the target moved  >2 mm from the predicted 2D BEV position are 1.1%/4.0%/7.8% and 1.3%/5.8%/11.6% for the 3D-modeled and 2D-only tracking, respectively. The corresponding average BEV RMS errors are 0.67/0.90/1.13 mm and 0.79/1.10/1.37 mm. Compared to the 2D method, the 3D method reduced the average RMS unresolved motion along the beam direction from ~3 mm to ~1 mm, resulting in on average only  <1% dosimetric advantage in the depth direction. Only for a small fraction of the patients, when tracking latency is long, the 3D-modeled method showed significant improvement of BEV tracking accuracy, indicating potential dosimetric advantage. However, if the tracking latency is short (~150 ms or less), those improvements are limited. Therefore, 2D BEV tracking has sufficient targeting accuracy for most clinical cases. The 3D technique is, however, still important in solving the MLC blockage problem

  13. The Structure of Liquid and Amorphous Hafnia

    Directory of Open Access Journals (Sweden)

    Leighanne C. Gallington

    2017-11-01

    Full Text Available Understanding the atomic structure of amorphous solids is important in predicting and tuning their macroscopic behavior. Here, we use a combination of high-energy X-ray diffraction, neutron diffraction, and molecular dynamics simulations to benchmark the atomic interactions in the high temperature stable liquid and low-density amorphous solid states of hafnia. The diffraction results reveal an average Hf–O coordination number of ~7 exists in both the liquid and amorphous nanoparticle forms studied. The measured pair distribution functions are compared to those generated from several simulation models in the literature. We have also performed ab initio and classical molecular dynamics simulations that show density has a strong effect on the polyhedral connectivity. The liquid shows a broad distribution of Hf–Hf interactions, while the formation of low-density amorphous nanoclusters can reproduce the sharp split peak in the Hf–Hf partial pair distribution function observed in experiment. The agglomeration of amorphous nanoparticles condensed from the gas phase is associated with the formation of both edge-sharing and corner-sharing HfO6,7 polyhedra resembling that observed in the monoclinic phase.

  14. Micro-scale prediction method for API-solubility in polymeric matrices and process model for forming amorphous solid dispersion by hot-melt extrusion.

    Science.gov (United States)

    Bochmann, Esther S; Neumann, Dirk; Gryczke, Andreas; Wagner, Karl G

    2016-10-01

    A new predictive micro-scale solubility and process model for amorphous solid dispersions (ASDs) by hot-melt extrusion (HME) is presented. It is based on DSC measurements consisting of an annealing step and a subsequent analysis of the glass transition temperature (Tg). The application of a complex mathematical model (BCKV-equation) to describe the dependency of Tg on the active pharmaceutical ingredient (API)/polymer ratio, enables the prediction of API solubility at ambient conditions (25°C). Furthermore, estimation of the minimal processing temperature for forming ASDs during HME trials could be defined and was additionally confirmed by X-ray powder diffraction data. The suitability of the DSC method was confirmed with melt rheological trials (small amplitude oscillatory system). As an example, ball milled physical mixtures of dipyridamole, indomethacin, itraconazole and nifedipine in poly(vinylpyrrolidone-co-vinylacetate) (copovidone) and polyvinyl caprolactam-polyvinyl acetate-polyethylene glycol graft copolymer (Soluplus®) were used. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Interacting Multiple Model (IMM) Fifth-Degree Spherical Simplex-Radial Cubature Kalman Filter for Maneuvering Target Tracking.

    Science.gov (United States)

    Liu, Hua; Wu, Wen

    2017-06-13

    For improving the tracking accuracy and model switching speed of maneuvering target tracking in nonlinear systems, a new algorithm named the interacting multiple model fifth-degree spherical simplex-radial cubature Kalman filter (IMM5thSSRCKF) is proposed in this paper. The new algorithm is a combination of the interacting multiple model (IMM) filter and the fifth-degree spherical simplex-radial cubature Kalman filter (5thSSRCKF). The proposed algorithm makes use of Markov process to describe the switching probability among the models, and uses 5thSSRCKF to deal with the state estimation of each model. The 5thSSRCKF is an improved filter algorithm, which utilizes the fifth-degree spherical simplex-radial rule to improve the filtering accuracy. Finally, the tracking performance of the IMM5thSSRCKF is evaluated by simulation in a typical maneuvering target tracking scenario. Simulation results show that the proposed algorithm has better tracking performance and quicker model switching speed when disposing maneuver models compared with the interacting multiple model unscented Kalman filter (IMMUKF), the interacting multiple model cubature Kalman filter (IMMCKF) and the interacting multiple model fifth-degree cubature Kalman filter (IMM5thCKF).

  16. Interacting Multiple Model (IMM Fifth-Degree Spherical Simplex-Radial Cubature Kalman Filter for Maneuvering Target Tracking

    Directory of Open Access Journals (Sweden)

    Hua Liu

    2017-06-01

    Full Text Available For improving the tracking accuracy and model switching speed of maneuvering target tracking in nonlinear systems, a new algorithm named the interacting multiple model fifth-degree spherical simplex-radial cubature Kalman filter (IMM5thSSRCKF is proposed in this paper. The new algorithm is a combination of the interacting multiple model (IMM filter and the fifth-degree spherical simplex-radial cubature Kalman filter (5thSSRCKF. The proposed algorithm makes use of Markov process to describe the switching probability among the models, and uses 5thSSRCKF to deal with the state estimation of each model. The 5thSSRCKF is an improved filter algorithm, which utilizes the fifth-degree spherical simplex-radial rule to improve the filtering accuracy. Finally, the tracking performance of the IMM5thSSRCKF is evaluated by simulation in a typical maneuvering target tracking scenario. Simulation results show that the proposed algorithm has better tracking performance and quicker model switching speed when disposing maneuver models compared with the interacting multiple model unscented Kalman filter (IMMUKF, the interacting multiple model cubature Kalman filter (IMMCKF and the interacting multiple model fifth-degree cubature Kalman filter (IMM5thCKF.

  17. Multi-component fiber track modelling of diffusion-weighted magnetic resonance imaging data

    Directory of Open Access Journals (Sweden)

    Yasser M. Kadah

    2010-01-01

    Full Text Available In conventional diffusion tensor imaging (DTI based on magnetic resonance data, each voxel is assumed to contain a single component having diffusion properties that can be fully represented by a single tensor. Even though this assumption can be valid in some cases, the general case involves the mixing of components, resulting in significant deviation from the single tensor model. Hence, a strategy that allows the decomposition of data based on a mixture model has the potential of enhancing the diagnostic value of DTI. This project aims to work towards the development and experimental verification of a robust method for solving the problem of multi-component modelling of diffusion tensor imaging data. The new method demonstrates significant error reduction from the single-component model while maintaining practicality for clinical applications, obtaining more accurate Fiber tracking results.

  18. Short range order in amorphous polycondensates

    Energy Technology Data Exchange (ETDEWEB)

    Lamers, C.; Richter, D.; Schweika, W. [Forschungszentrum Juelich GmbH (Germany). Inst. fuer Festkoerperforschung; Batoulis, J.; Sommer, K. [Bayer AG, Leverkusen (Germany); Cable, J.W. [Oak Ridge National Lab., TN (United States); Shapiro, S.M. [Brookhaven National Lab., Upton, NY (United States)

    1992-12-01

    The static coherent structure factors S(Q) of the polymer glass Bisphenol-A-Polycarbonate and its chemical variation Bisphenol-A- Polyctherkctone- both in differently deuterated versions- have been measured by spin polarized neutron scattering. The method of spin polarization analysis provided an experimental separation of coherent and incoherent scattering and a reliable intensity calibration. Results are compared to structure factors calculated for model structures which were obtained by ``amorphous cell`` computer simulations. In general reasonable agreement is found between experiment and simulation; however, certain discrepancies hint at an insufficient structural relaxation in the amorphous cell method. 15 refs, 1 fig, 1 tab.

  19. The cost-effectiveness of tracking newborns with bilateral hearing impairment in Bavaria: a decision-analytic model

    Directory of Open Access Journals (Sweden)

    Langer Astrid

    2012-11-01

    Full Text Available Abstract Background Although several countries, including Germany, have established newborn hearing screening programmes for early detection and treatment of newborns with hearing impairments, nationwide tracking systems for follow-up of newborns with positive test results until diagnosis of hearing impairment have often not been implemented. However, a recent study on universal newborn hearing screening in Bavaria showed that, in a high proportion of newborns, early diagnosis was only possible with the use of a tracking system. The aim of this study was, therefore, to assess the cost-effectiveness of tracking newborns with bilateral hearing impairment in Bavaria. Methods Data from a Bavarian pilot project on newborn hearing screening and Bavarian newborn hearing screening facilities were used to assess the cost-effectiveness of the inclusion of a tracking system within a newborn hearing screening programme. A model-based cost-effectiveness analysis was conducted. The time horizon of the model was limited to the newborn hearing screening programme. Costs of the initial hearing screening test and subsequent tests were included, as well as costs of diagnosis and costs of tracking. The outcome measure of the economic analysis was the cost per case of bilateral hearing impairment detected. In order to reflect uncertainty, deterministic and probabilistic sensitivity analyses were performed. Results The incremental cost-effectiveness ratio of tracking vs. no tracking was €1,697 per additional case of bilateral hearing impairment detected. Conclusions Compared with no tracking, tracking resulted in more cases of bilateral hearing impairment detected as well as higher costs. If society is willing to pay at least €1,697 per additional case of bilateral hearing impairment detected, tracking can be recommended.

  20. Modeling Self-Occlusions/Disocclusions in Dynamic Shape and Appearance Tracking for Obtaining Precise Shape

    KAUST Repository

    Yang, Yanchao

    2013-05-01

    We present a method to determine the precise shape of a dynamic object from video. This problem is fundamental to computer vision, and has a number of applications, for example, 3D video/cinema post-production, activity recognition and augmented reality. Current tracking algorithms that determine precise shape can be roughly divided into two categories: 1) Global statistics partitioning methods, where the shape of the object is determined by discriminating global image statistics, and 2) Joint shape and appearance matching methods, where a template of the object from the previous frame is matched to the next image. The former is limited in cases of complex object appearance and cluttered background, where global statistics cannot distinguish between the object and background. The latter is able to cope with complex appearance and a cluttered background, but is limited in cases of camera viewpoint change and object articulation, which induce self-occlusions and self-disocclusions of the object of interest. The purpose of this thesis is to model self-occlusion/disocclusion phenomena in a joint shape and appearance tracking framework. We derive a non-linear dynamic model of the object shape and appearance taking into account occlusion phenomena, which is then used to infer self-occlusions/disocclusions, shape and appearance of the object in a variational optimization framework. To ensure robustness to other unmodeled phenomena that are present in real-video sequences, the Kalman filter is used for appearance updating. Experiments show that our method, which incorporates the modeling of self-occlusion/disocclusion, increases the accuracy of shape estimation in situations of viewpoint change and articulation, and out-performs current state-of-the-art methods for shape tracking.

  1. Visual Trajectory-Tracking Model-Based Control for Mobile Robots

    Directory of Open Access Journals (Sweden)

    Andrej Zdešar

    2013-09-01

    Full Text Available In this paper we present a visual-control algorithm for driving a mobile robot along the reference trajectory. The configuration of the system consists of a two-wheeled differentially driven mobile robot that is observed by an overhead camera, which can be placed at arbitrary, but reasonable, inclination with respect to the ground plane. The controller must be capable of generating appropriate tangential and angular control velocities for the trajectory-tracking problem, based on the information received about the robot position obtained in the image. To be able to track the position of the robot through a sequence of images in real-time, the robot is marked with an artificial marker that can be distinguishably recognized by the image recognition subsystem. Using the property of differential flatness, a dynamic feedback compensator can be designed for the system, thereby extending the system into a linear form. The presented control algorithm for reference tracking combines a feedforward and a feedback loop, the structure also known as a two DOF control scheme. The feedforward part should drive the system to the vicinity of the reference trajectory and the feedback part should eliminate any errors that occur due to noise and other disturbances etc. The feedforward control can never achieve accurate reference following, but this deficiency can be eliminated with the introduction of the feedback loop. The design of the model predictive control is based on the linear error model. The model predictive control is given in analytical form, so the computational burden is kept at a reasonable level for real-time implementation. The control algorithm requires that a reference trajectory is at least twice differentiable function. A suitable approach to design such a trajectory is by exploiting some useful properties of the Bernstein-Bézier parametric curves. The simulation experiments as well as real system experiments on a robot normally used in the

  2. Amorphous Semiconductor Alloys

    Science.gov (United States)

    Madan, Arun

    1985-08-01

    Amorphous silicon (a-Si) based alloys have attracted a considerable amount of interest because of their applications in a wide variety of technologies. However, the major effort has concentrated on inexpensive photovoltaic device applications and has moved from a laboratory curiosity in the early 1970's to viable commercial applications in the 1980's. Impressive progress in this field has been made since the group at University of Dundee demonstrated that a low defect, device quality hydrogenated amorphous silicon (a-Si:H) 12 material could be produced using the radio frequency (r.f.) glow discharge in SiH4 gas ' and that the material could be doped n- and p-type.3 These results spurred a worldwide interest in a-Si based alloys, especially for photovoltaic devices which has resulted in a conversion efficiency approaching 12%. There is now a quest for even higher conversion efficiencies by using the multijunction cell approach. This necessitates the synthesis of new materials of differing bandgaps, which in principle amorphous semiconductors can achieve. In this article, we review some of this work and consider from a device and a materials point of view the hurdles which have to be overcome before this type of concept can be realized.

  3. Radial dose distribution around an energetic heavy ion and an ion track structure model

    Energy Technology Data Exchange (ETDEWEB)

    Furukawa, Katsutoshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Ohno, Shin-ichi; Namba, Hideki; Taguchi, Mitsumasa; Watanabe, Ritsuko

    1997-03-01

    Ionization currents produced in a small wall-less ionization chamber located at varying distance from the 200 MeV Ni{sup 12+} ion`path traversing Ar gas were measured and utilized to construct a track structure model. Using the LET value of 200 MeV Ni{sup 12+} and G(Fe{sup 3+}) in Fricke solutions (= 15.4) for fast electrons, we estimate G(Fe{sup 3+}) for this ion to be 5.0. (author)

  4. A low-complexity interacting multiple model filter for maneuvering target tracking

    KAUST Repository

    Khalid, Syed Safwan

    2017-01-22

    In this work, we address the target tracking problem for a coordinate-decoupled Markovian jump-mean-acceleration based maneuvering mobility model. A novel low-complexity alternative to the conventional interacting multiple model (IMM) filter is proposed for this class of mobility models. The proposed tracking algorithm utilizes a bank of interacting filters where the interactions are limited to the mixing of the mean estimates, and it exploits a fixed off-line computed Kalman gain matrix for the entire filter bank. Consequently, the proposed filter does not require matrix inversions during on-line operation which significantly reduces its complexity. Simulation results show that the performance of the low-complexity proposed scheme remains comparable to that of the traditional (highly-complex) IMM filter. Furthermore, we derive analytical expressions that iteratively evaluate the transient and steady-state performance of the proposed scheme, and establish the conditions that ensure the stability of the proposed filter. The analytical findings are in close accordance with the simulated results.

  5. Model-based extended quaternion Kalman filter to inertial orientation tracking of arbitrary kinematic chains.

    Science.gov (United States)

    Szczęsna, Agnieszka; Pruszowski, Przemysław

    2016-01-01

    Inertial orientation tracking is still an area of active research, especially in the context of out-door, real-time, human motion capture. Existing systems either propose loosely coupled tracking approaches where each segment is considered independently, taking the resulting drawbacks into account, or tightly coupled solutions that are limited to a fixed chain with few segments. Such solutions have no flexibility to change the skeleton structure, are dedicated to a specific set of joints, and have high computational complexity. This paper describes the proposal of a new model-based extended quaternion Kalman filter that allows for estimation of orientation based on outputs from the inertial measurements unit sensors. The filter considers interdependencies resulting from the construction of the kinematic chain so that the orientation estimation is more accurate. The proposed solution is a universal filter that does not predetermine the degree of freedom at the connections between segments of the model. To validation the motion of 3-segments single link pendulum captured by optical motion capture system is used. The next step in the research will be to use this method for inertial motion capture with a human skeleton model.

  6. Neutron and X-ray diffraction and empirical potential structure refinement modelling of magnesium stabilised amorphous calcium carbonate

    DEFF Research Database (Denmark)

    Cobourne, G.; Mountjoy, G.; Rodriguez Blanco, Juan Diego

    2014-01-01

    potential structure refinement method has been used to make a model of magnesium-stabilised ACC and the results revealed a fair agreement with the experimental diffraction data. The model has well-defined CO3 and H2O molecules. The average coordination number of Ca is 7.4 and is composed of 6.8 oxygen atoms...

  7. Neutron diffraction studies of amorphous solids

    International Nuclear Information System (INIS)

    Wright, A.C.

    1983-01-01

    A brief survey is presented of the role of neutron diffraction in structural studies of amorphous solids. The inherent limitations of the diffraction technique are discussed, together with modern instrumentation and methods for separating individual component correlation functions. An introduction is given to the use of modelling and the extraction of structural parameters from experimental data. (author)

  8. In vitro and in vivo evaluation of amorphous solid dispersions generated by different bench-scale processes, using griseofulvin as a model compound.

    Science.gov (United States)

    Chiang, Po-Chang; Cui, Yong; Ran, Yingqing; Lubach, Joe; Chou, Kang-Jye; Bao, Linda; Jia, Wei; La, Hank; Hau, Jonathan; Sambrone, Amy; Qin, Ann; Deng, Yuzhong; Wong, Harvey

    2013-04-01

    Drug polymer-based amorphous solid dispersions (ASD) are widely used in the pharmaceutical industry to improve bioavailability for poorly water-soluble compounds. Spray-drying is the most common process involved in the manufacturing of ASD material. However, spray-drying involves a high investment of material quantity and time. Lower investment manufacturing processes such as fast evaporation and freeze-drying (lyophilization) have been developed to manufacture ASD at the bench level. The general belief is that the overall performance of ASD material is thermodynamically driven and should be independent of the manufacturing process. However, no formal comparison has been made to assess the in vivo performance of material generated by different processes. This study compares the in vitro and in vivo properties of ASD material generated by fast evaporation, lyophilization, and spray-drying methods using griseofulvin as a model compound and hydroxypropyl methylcellulose acetate succinate as the polymer matrix. Our data suggest that despite minor differences in the formulation release properties and stability of the ASD materials, the overall exposure is comparable between the three manufacturing processes under the conditions examined. These results suggest that fast evaporation and lyophilization may be suitable to generate ASD material for oral evaluation. However, caution should be exercised since the general applicability of the present findings will need to be further evaluated.

  9. Segment Tracking via a Spatiotemporal Linking Process including Feedback Stabilization in an n-D Lattice Model

    Directory of Open Access Journals (Sweden)

    Florentin Wörgötter

    2009-11-01

    Full Text Available Model-free tracking is important for solving tasks such as moving-object tracking and action recognition in cases where no prior object knowledge is available. For this purpose, we extend the concept of spatially synchronous dynamics in spin-lattice models to the spatiotemporal domain to track segments within an image sequence. The method is related to synchronization processes in neural networks and based on superparamagnetic clustering of data. Spin interactions result in the formation of clusters of correlated spins, providing an automatic labeling of corresponding image regions. The algorithm obeys detailed balance. This is an important property as it allows for consistent spin-transfer across subsequent frames, which can be used for segment tracking. Therefore, in the tracking process the correct equilibrium will always be found, which is an important advance as compared with other more heuristic tracking procedures. In the case of long image sequences, i.e., movies, the algorithm is augmented with a feedback mechanism, further stabilizing segment tracking.

  10. Modelling low energy electron and positron tracks in biologically relevant media

    International Nuclear Information System (INIS)

    Blanco, F.; Munoz, A.; Almeida, D.; Ferreira da Silva, F.; Limao-Vieira, P.; Fuss, M.C.; Sanz, A.G.; Garcia, G.

    2013-01-01

    This colloquium describes an approach to incorporate into radiation damage models the effect of low and intermediate energy (0-100 eV) electrons and positrons, slowing down in biologically relevant materials (water and representative biomolecules). The core of the modelling procedure is a C++ computing programme named 'Low Energy Particle Track Simulation (LEPTS)', which is compatible with available general purpose Monte Carlo packages. Input parameters are carefully selected from theoretical and experimental cross section data and energy loss distribution functions. Data sources used for this purpose are reviewed showing examples of electron and positron cross section and energy loss data for interactions with different media of increasing complexity: atoms, molecules, clusters and condense matter. Finally, we show how such a model can be used to develop an effective dosimetric tool at the molecular level (i.e. nanodosimetry). Recent experimental developments to study the fragmentation induced in biologically material by charge transfer from neutrals and negative ions are also included. (authors)

  11. Numerical Simulation of Suspended Sediment Transportation Based on Particle Tracking Model

    Science.gov (United States)

    Yao, W. W.; Ying, C.; Mu, J. B.

    2017-08-01

    Coastal engineering that carried out on the muddy seabed were always accompanied by diffusion of suspended sediment, and that would impact on the surrounding marine environment. A 2-D tidal flow mathematical model of the Yueqing Bay was established based on the Lagrange particle tracking model, the diffusion of suspended sediment in pile foundation construction process of a new wharf in the Yueqing Bay was simulated through a continuous moving points method, the calculation results were compared with the one calculated by the traditional convection diffusion method, it showed that the results calculated from the two different methods were similar, therefore it proved the suitability of the Lagrange particle tracing model in the suspended sediment diffusion problems.

  12. Towards a better characterisation of radiation quality using track structure models

    Energy Technology Data Exchange (ETDEWEB)

    Kiefer, J.; Brend`amour, M. [Strahlenzentrum der Justus-Liebig-Universitat, Leihgesterner Weg, Giessen (Germany); Schmollack, J.U. [HMI, Berlin, (Germany)

    1997-03-01

    Many current track structure calculations are based on Monte-Carlo simulations which have to be performed for each individual case. Analytical models, on the other hand supply general formulations which can easily adapted to different conditions. Since they are continuous they oversimplify the real situation and are not suitable to be applied to very specific molecular structures. Nevertheless they are very useful and may even be more realistic than Monte-Carlo models as the molecules in the cell are more complicated than a composition of simple geometrical forms. Analytical models can be used to derive distributions of specific energies in various site sizes, range restricted LET and proximity functions. Experimental data support the main findings of these approaches. The quantities derived may serve as better descriptors of radiation quality than LET which is obviously inadequate but still widely used. The paper will illustrate these points by giving experimental examples both from the physical and the biological field. (authors)

  13. Dynamic Modelling and Trajectory Tracking of Parallel Manipulator with Flexible Link

    Directory of Open Access Journals (Sweden)

    Chen Zhengsheng

    2013-09-01

    Full Text Available This paper mainly focuses on dynamic modelling and real-time control for a parallel manipulator with flexible link. The Lagrange principle and assumed modes method (AMM substructure technique is presented to formulate the dynamic modelling of a two-degrees-of-freedom (DOF parallel manipulator with flexible links. Then, the singular perturbation technique (SPT is used to decompose the nonlinear dynamic system into slow time-scale and fast time-scale subsystems. Furthermore, the SPT is employed to transform the differential algebraic equations (DAEs for kinematic constraints into explicit ordinary differential equations (ODEs, which makes real-time control possible. In addition, a novel composite control scheme is presented; the computed torque control is applied for a slow subsystem and the H∞ technique for the fast subsystem, taking account of the model uncertainty and outside disturbance. The simulation results show the composite control can effectively achieve fast and accurate tracking control.

  14. Facial Feature Tracking Using Efficient Particle Filter and Active Appearance Model

    Directory of Open Access Journals (Sweden)

    Durkhyun Cho

    2014-09-01

    Full Text Available For natural human-robot interaction, the location and shape of facial features in a real environment must be identified. One robust method to track facial features is by using a particle filter and the active appearance model. However, the processing speed of this method is too slow for utilization in practice. In order to improve the efficiency of the method, we propose two ideas: (1 changing the number of particles situationally, and (2 switching the prediction model depending upon the degree of the importance of each particle using a combination strategy and a clustering strategy. Experimental results show that the proposed method is about four times faster than the conventional method using a particle filter and the active appearance model, without any loss of performance.

  15. The Stabilization of Amorphous Zopiclone in an Amorphous Solid Dispersion.

    Science.gov (United States)

    Milne, Marnus; Liebenberg, Wilna; Aucamp, Marique

    2015-10-01

    Zopiclone is a poorly soluble psychotherapeutic agent. The aim of this study was to prepare and characterize an amorphous form of zopiclone as well as the characterization and performance of a stable amorphous solid dispersion. The amorphous form was prepared by the well-known method of quench-cooling of the melt. The solid dispersion was prepared by a solvent evaporation method of zopiclone, polyvinylpyrrolidone-25 (PVP-25), and methanol, followed by freeze-drying. The physico-chemical properties and stability of amorphous zopiclone and the solid dispersion was studied using differential scanning calorimetry (DSC), infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), hot-stage microscopy (HSM), X-ray diffractometry (XRD), solubility, and dissolution studies. The zopiclone amorphous solid-state form was determined to be a fragile glass; it was concluded that the stability of the amorphous form is influenced by both temperature and water. Exposure of amorphous zopiclone to moisture results in rapid transformation of the amorphous form to the crystalline dihydrated form. In comparison, the amorphous solid dispersion proved to be more stable with increased aqueous solubility.

  16. The Dynamic Model Embed in Augmented Graph Cuts for Robust Hand Tracking and Segmentation in Videos

    Directory of Open Access Journals (Sweden)

    Jun Wan

    2014-01-01

    Full Text Available Segmenting human hand is important in computer vision applications, for example, sign language interpretation, human computer interaction, and gesture recognition. However, some serious bottlenecks still exist in hand localization systems such as fast hand motion capture, hand over face, and hand occlusions on which we focus in this paper. We present a novel method for hand tracking and segmentation based on augmented graph cuts and dynamic model. First, an effective dynamic model for state estimation is generated, which correctly predicts the location of hands probably having fast motion or shape deformations. Second, new energy terms are brought into the energy function to develop augmented graph cuts based on some cues, namely, spatial information, hand motion, and chamfer distance. The proposed method successfully achieves hand segmentation even though the hand passes over other skin-colored objects. Some challenging videos are provided in the case of hand over face, hand occlusions, dynamic background, and fast motion. Experimental results demonstrate that the proposed method is much more accurate than other graph cuts-based methods for hand tracking and segmentation.

  17. Mitigating the Goldilocks effect: the effects of different substrate models on track formation potential.

    Science.gov (United States)

    Falkingham, Peter L; Hage, Julian; Bäker, Martin

    2014-11-01

    In ichnology, the Goldilocks effect describes a scenario in which a substrate must be 'just right' in order for tracks to form-too soft, the animal will be unable to traverse the area, and too firm, the substrate will not deform. Any given substrate can therefore only preserve a range of tracks from those animals which exert an underfoot pressure at approximately the yield strength of the sediment. However, rarely are substrates vertically homogeneous for any great depth, varying either due to heterogeneity across sediment layers, or from mechanical behaviour such as strain hardening. Here, we explore the specificity of the Goldilocks effect in a number of virtual substrates simulated using finite-element analysis. We find that the inclusion of strain hardening into the model increases the potential range of trackmaker sizes somewhat, compared with a simple elastic-perfectly plastic model. The simulation of a vertically heterogeneous, strain hardening substrate showed a much larger range of potential trackmakers than strain hardening alone. We therefore show that the Goldilocks effect is lessened to varying degrees by the inclusion of more realistic soil parameters, though there still remains an upper and lower limit to the size of trackmaker able to traverse the area while leaving footprints.

  18. Assessing the effects of anthropogenic aerosols on Pacific storm track using a multiscale global climate model.

    Science.gov (United States)

    Wang, Yuan; Wang, Minghuai; Zhang, Renyi; Ghan, Steven J; Lin, Yun; Hu, Jiaxi; Pan, Bowen; Levy, Misti; Jiang, Jonathan H; Molina, Mario J

    2014-05-13

    Atmospheric aerosols affect weather and global general circulation by modifying cloud and precipitation processes, but the magnitude of cloud adjustment by aerosols remains poorly quantified and represents the largest uncertainty in estimated forcing of climate change. Here we assess the effects of anthropogenic aerosols on the Pacific storm track, using a multiscale global aerosol-climate model (GCM). Simulations of two aerosol scenarios corresponding to the present day and preindustrial conditions reveal long-range transport of anthropogenic aerosols across the north Pacific and large resulting changes in the aerosol optical depth, cloud droplet number concentration, and cloud and ice water paths. Shortwave and longwave cloud radiative forcing at the top of atmosphere are changed by -2.5 and +1.3 W m(-2), respectively, by emission changes from preindustrial to present day, and an increased cloud top height indicates invigorated midlatitude cyclones. The overall increased precipitation and poleward heat transport reflect intensification of the Pacific storm track by anthropogenic aerosols. Hence, this work provides, for the first time to the authors' knowledge, a global perspective of the effects of Asian pollution outflows from GCMs. Furthermore, our results suggest that the multiscale modeling framework is essential in producing the aerosol invigoration effect of deep convective clouds on a global scale.

  19. Modeling and Robust Trajectory Tracking Control for a Novel Six-Rotor Unmanned Aerial Vehicle

    Directory of Open Access Journals (Sweden)

    Chengshun Yang

    2013-01-01

    Full Text Available Modeling and trajectory tracking control of a novel six-rotor unmanned aerial vehicle (UAV is concerned to solve problems such as smaller payload capacity and lack of both hardware redundancy and anticrosswind capability for quad-rotor. The mathematical modeling for the six-rotor UAV is developed on the basis of the Newton-Euler formalism, and a second-order sliding-mode disturbance observer (SOSMDO is proposed to reconstruct the disturbances of the rotational dynamics. In consideration of the under-actuated and strong coupling properties of the six-rotor UAV, a nested double loops trajectory tracking control strategy is adopted. In the outer loop, a position error PID controller is designed, of which the task is to compare the desired trajectory with real position of the six-rotor UAV and export the desired attitude angles to the inner loop. In the inner loop, a rapid-convergent nonlinear differentiator (RCND is proposed to calculate the derivatives of the virtual control signal, instead of using the analytical differentiation, to avoid “differential expansion” in the procedure of the attitude controller design. Finally, the validity and effectiveness of the proposed technique are demonstrated by the simulation results.

  20. Analyzing Ocean Tracks: A model for student engagement in authentic scientific practices using data

    Science.gov (United States)

    Krumhansl, K.; Krumhansl, R.; Brown, C.; DeLisi, J.; Kochevar, R.; Sickler, J.; Busey, A.; Mueller-Northcott, J.; Block, B.

    2013-12-01

    The collection of large quantities of scientific data has not only transformed science, but holds the potential to transform teaching and learning by engaging students in authentic scientific work. Furthermore, it has become imperative in a data-rich world that students gain competency in working with and interpreting data. The Next Generation Science Standards reflect both the opportunity and need for greater integration of data in science education, and emphasize that both scientific knowledge and practice are essential elements of science learning. The process of enabling access by novice learners to data collected and used by experts poses significant challenges, however, recent research has demonstrated that barriers to student learning with data can be overcome by the careful design of data access and analysis tools that are specifically tailored to students. A group of educators at Education Development Center, Inc. (EDC) and scientists at Stanford University's Hopkins Marine Station are collaborating to develop and test a model for student engagement with scientific data using a web-based platform. This model, called Ocean Tracks: Investigating Marine Migrations in a Changing Ocean, provides students with the ability to plot and analyze tracks of migrating marine animals collected through the Tagging of Pacific Predators program. The interface and associated curriculum support students in identifying relationships between animal behavior and physical oceanographic variables (e.g. SST, chlorophyll, currents), making linkages between the living world and climate. Students are also supported in investigating possible sources of human impact to important biodiversity hotspots in the Pacific Ocean. The first round of classroom testing revealed that students were able to easily access and display data on the interface, and collect measurements from the animal tracks and oceanographic data layers. They were able to link multiple types of data to draw powerful

  1. Transport, Interfaces, and Modeling in Amorphous Silicon Based Solar Cells: Final Technical Report, 11 February 2002 - 30 September 2006

    Energy Technology Data Exchange (ETDEWEB)

    Schiff, E. A.

    2008-10-01

    Results for a-Si characteristics/modeling; photocarrier drift mobilities in a-Si;H, ..mu..c-Si:H, CIGS; hole-conducting polymers as p-layer for a-Si and c-Si; IR spectra of p/i and n/i interfaces in a-Si.

  2. Modelling of a Double-Track Railway Contact System Electric Field Intensity

    Science.gov (United States)

    Belinsky, Stanislav; Khanzhina, Olga; Sidorov, Alexander

    2017-12-01

    Working conditions of personnel that serves contact system (CS) are affected by factors including health and safety, security and working hours (danger of rolling stock accidents, danger of electric shock strokes, work at height, severity and tension of work, increased noise level, etc.) Low frequency electromagnetic fields as part of both electric and magnetic fields are among of the most dangerous and harmful factors. These factors can affect not only the working personnel, but also a lot of people, who do not work with the contact system itself, but could be influenced by electromagnetic field as the result of their professional activity. People, who use public transport or live not far from the electrified lines, are endangered by these factors as well. There are results of the theoretical researches in which low frequency electric fields of railway contact system were designed with the use of mathematical and computer modelling. Significant features of electric field distribution near double-track railway in presence or absence of human body were established. The studies showed the dependence of low frequency electric field parameters on the distance to the track axis, height, and presence or absence of human body. The obtained data were compared with permissible standards established in the Russian Federation and other countries with advanced electrified railway system. Evaluation of low frequency electric fields harmful effect on personnel is the main result of this work. It is also established, that location of personnel, voltage and current level, amount of tracks and other factors influence electric fields of contact systems.

  3. Model track studies on fouled ballast using ground penetrating radar and multichannel analysis of surface wave

    Science.gov (United States)

    Anbazhagan, P.; Lijun, Su; Buddhima, Indraratna; Cholachat, Rujikiatkamjorn

    2011-08-01

    Ballast fouling is created by the breakdown of aggregates or outside contamination by coal dust from coal trains, or from soil intrusion beneath rail track. Due to ballast fouling, the conditions of rail track can be deteriorated considerably depending on the type of fouling material and the degree of fouling. So far there is no comprehensive guideline available to identify the critical degree of fouling for different types of fouling materials. This paper presents the identification of degree of fouling and types of fouling using non-destructive testing, namely seismic surface-wave and ground penetrating radar (GPR) survey. To understand this, a model rail track with different degree of fouling has been constructed in Civil engineering laboratory, University of Wollongong, Australia. Shear wave velocity obtained from seismic survey has been employed to identify the degree of fouling and types of fouling material. It is found that shear wave velocity of fouled ballast increases initially, reaches optimum fouling point (OFP), and decreases when the fouling increases. The degree of fouling corresponding after which the shear wave velocity of fouled ballast will be smaller than that of clean ballast is called the critical fouling point (CFP). Ground penetrating radar with four different ground coupled antennas (500 MHz, 800 MHz, 1.6 GHz and 2.3 GHz) was also used to identify the ballast fouling condition. It is found that the 800 MHz ground coupled antenna gives a better signal in assessing the ballast fouling condition. Seismic survey is relatively slow when compared to GPR survey however it gives quantifiable results. In contrast, GPR survey is faster and better in estimating the depth of fouling.

  4. Sky-Hook Control and Kalman Filtering in Nonlinear Model of Tracked Vehicle Suspension System

    Directory of Open Access Journals (Sweden)

    Jurkiewicz Andrzej

    2017-09-01

    Full Text Available The essence of the undertaken topic is application of the continuous sky-hook control strategy and the Extended Kalman Filter as the state observer in the 2S1 tracked vehicle suspension system. The half-car model of this suspension system consists of seven logarithmic spiral springs and two magnetorheological dampers which has been described by the Bingham model. The applied continuous sky-hook control strategy considers nonlinear stiffness characteristic of the logarithmic spiral springs. The control is determined on estimates generated by the Extended Kalman Filter. Improve of ride comfort is verified by comparing simulation results, under the same driving conditions, of controlled and passive vehicle suspension systems.

  5. Steering Angle Control of Car for Dubins Path-tracking Using Model Predictive Control

    Science.gov (United States)

    Kusuma Rahma Putri, Dian; Subchan; Asfihani, Tahiyatul

    2018-03-01

    Car as one of transportation is inseparable from technological developments. About ten years, there are a lot of research and development on lane keeping system(LKS) which is a system that automaticaly controls the steering to keep the vehicle especially car always on track. This system can be developed for unmanned cars. Unmanned system car requires navigation, guidance and control which is able to direct the vehicle to move toward the desired path. The guidance system is represented by using Dubins-Path that will be controlled by using Model Predictive Control. The control objective is to keep the car’s movement that represented by dinamic lateral motion model so car can move according to the path appropriately. The simulation control on the four types of trajectories that generate the value for steering angle and steering angle changes are at the specified interval.

  6. Discrete Model Predictive Control-Based Maximum Power Point Tracking for PV Systems: Overview and Evaluation

    DEFF Research Database (Denmark)

    Lashab, Abderezak; Sera, Dezso; Guerrero, Josep M.

    2018-01-01

    The main objective of this work is to provide an overview and evaluation of discrete model predictive controlbased maximum power point tracking (MPPT) for PV systems. A large number of MPC based MPPT methods have been recently introduced in the literature with very promising performance, however......, an in-depth investigation and comparison of these methods have not been carried out yet. Therefore, this paper has set out to provide an in-depth analysis and evaluation of MPC based MPPT methods applied to various common power converter topologies. The performance of MPC based MPPT is directly linked...... with the converter topology, and it is also affected by the accurate determination of the converter parameters, sensitivity to converter parameter variations is also investigated. The static and dynamic performance of the trackers are assessed according to the EN 50530 standard, using detailed simulation models...

  7. Randomly-fluctuating heterogeneous continuum model of a ballasted railway track

    Science.gov (United States)

    de Abreu Corrêa, Lucio; Quezada, Juan Carlos; Cottereau, Régis; d'Aguiar, Sofia Costa; Voivret, Charles

    2017-11-01

    This paper proposes a description of a granular medium as a stochastic heterogeneous continuum medium. The heterogeneity of the material properties field recreates the heterogeneous stress field in a granular medium. The stochastic approach means that only statistical information, easily available, is required to construct the model. The heterogeneous continuum model is Calibrated with respect to discrete simulations of a set of railway ballast samples. As they are continuum-based, the equilibrium equations can be solved on a large scale using a parallel implementation of an explicit time discretization scheme for the Finite Element Method. Simulations representative of the influence on the environment of the passage of a train on a ballasted railway track clearly show the influence of the heterogeneity. These simulations seem to correlate well with previously unexplained overly damped measurements in the free field.

  8. Photovoltaic System Modeling with Fuzzy Logic Based Maximum Power Point Tracking Algorithm

    Directory of Open Access Journals (Sweden)

    Hasan Mahamudul

    2013-01-01

    Full Text Available This paper represents a novel modeling technique of PV module with a fuzzy logic based MPPT algorithm and boost converter in Simulink environment. The prime contributions of this work are simplification of PV modeling technique and implementation of fuzzy based MPPT system to track maximum power efficiently. The main highlighted points of this paper are to demonstrate the precise control of the duty cycle with respect to various atmospheric conditions, illustration of PV characteristic curves, and operation analysis of the converter. The proposed system has been applied for three different PV modules SOLKAR 36 W, BP MSX 60 W, and KC85T 87 W. Finally the resultant data has been compared with the theoretical prediction and company specified value to ensure the validity of the system.

  9. Conception and modelling of photo-detection pixels. PIN photodiodes conceived in amorphous silicon for particles detection

    International Nuclear Information System (INIS)

    Negru, R.

    2008-06-01

    The research done has revealed that the a-Si:H is a material ideally suited for the detection of particles, while being resistant to radiation. It also has a low manufacturing cost, is compatible with existing technology and can be deposited over large areas. Thus, despite the low local mobility of charges (30 cm 2 /V/s), a-Si:H is a material of particular interest for manufacturing high-energy particle detection pixels. As a consequence of this, we have studied the feasibility of an experimental pixel stacked structure based on a-Si:H as a basic sensor element for an electromagnetic calorimeter. The structure of such a pixel consists of different components. First, a silicon PIN diode in a-Si:H is fabricated, followed by a bias resistor and a decoupling capacitor. Before such a structure is made and in order to optimize its design, it is essential to have an efficient behavioural model of the various components. Thus, our primary goal was to develop a two-dimensional physical model of the PIN diode using the SILVACO finite element calculation software. This a-Si:H PIN diode two-dimensional physical model allowed us to study the problem of crosstalk between pixels in a matrix structure of detectors. In particular, we concentrated on the leakage current and the current generated in the volume between neighbouring pixels. The successful implementation of this model in SPICE ensures its usefulness in other professional simulators and especially its integration into a complete electronic structure (PIN diode, bias resistor, decoupling capacity and low noise amplifier). Thanks to these modelling tools, we were able to simulate PIN diode structures in a-Si:H with different thicknesses and different dimensions. These simulations have allowed us to predict that the thicker structures are relevant to the design of the pixel detectors for high energy physics. Applications in astronomy, medical imaging and the analysis of the failure of silicon integrated circuits, can also

  10. Multi-scale simulation of structural heterogeneity of swift-heavy ion tracks in complex oxides

    Science.gov (United States)

    Wang, Jianwei; Lang, Maik; Ewing, Rodney C.; Becker, Udo

    2013-04-01

    Tracks formed by swift-heavy ion irradiation, 2.2 GeV Au, of isometric Gd2Ti2O7 pyrochlore and orthorhombic Gd2TiO5 were modeled using the thermal-spike model combined with a molecular-dynamics simulation. The thermal-spike model was used to calculate the energy dissipation over time and space. Using the time, space, and energy profile generated from the thermal-spike model, the molecular-dynamics simulations were performed to model the atomic-scale evolution of the tracks. The advantage of the combination of these two methods, which uses the output from the continuum model as an input for the atomistic model, is that it provides a means of simulating the coupling of the electronic and atomic subsystems and provides simultaneously atomic-scale detail of the track structure and morphology. The simulated internal structure of the track consists of an amorphous core and a shell of disordered, but still periodic, domains. For Gd2Ti2O7, the shell region has a disordered pyrochlore with a defect fluorite structure and is relatively thick and heterogeneous with different degrees of disordering. For Gd2TiO5, the disordered region is relatively small as compared with Gd2Ti2O7. In the simulation, ‘facets’, which are surfaces with definite crystallographic orientations, are apparent around the amorphous core and more evident in Gd2TiO5 along [010] than [001], suggesting an orientational dependence of the radiation response. These results show that track formation is controlled by the coupling of several complex processes, involving different degrees of amorphization, disordering, and dynamic annealing. Each of the processes depends on the mass and energy of the energetic ion, the properties of the material, and its crystallographic orientation with respect to the incident ion beam.

  11. CWI at TREC 2012, KBA track and Session Track

    NARCIS (Netherlands)

    S. Araújo (Samur); C. Boscarino (Corrado); G.G. Gebremeskel (Gebre); J. He (Jiyin); A.P. de Vries (Arjen); E.M. Voorhees; L. P. Buckland (Buckland, Lori P.)

    2013-01-01

    htmlabstractWe participated in two tracks: Knowledge Base Acceleration (KBA) Track and Session Track. In the KBA track, we focused on experi- menting with different approaches as it is the first time the track is launched. We experimented with supervised and unsupervised re- trieval models. Our

  12. Tracking instantaneous entropy in heartbeat dynamics through inhomogeneous point-process nonlinear models.

    Science.gov (United States)

    Valenza, Gaetano; Citi, Luca; Scilingo, Enzo Pasquale; Barbieri, Riccardo

    2014-01-01

    Measures of entropy have been proved as powerful quantifiers of complex nonlinear systems, particularly when applied to stochastic series of heartbeat dynamics. Despite the remarkable achievements obtained through standard definitions of approximate and sample entropy, a time-varying definition of entropy characterizing the physiological dynamics at each moment in time is still missing. To this extent, we propose two novel measures of entropy based on the inho-mogeneous point-process theory. The RR interval series is modeled through probability density functions (pdfs) which characterize and predict the time until the next event occurs as a function of the past history. Laguerre expansions of the Wiener-Volterra autoregressive terms account for the long-term nonlinear information. As the proposed measures of entropy are instantaneously defined through such probability functions, the proposed indices are able to provide instantaneous tracking of autonomic nervous system complexity. Of note, the distance between the time-varying phase-space vectors is calculated through the Kolmogorov-Smirnov distance of two pdfs. Experimental results, obtained from the analysis of RR interval series extracted from ten healthy subjects during stand-up tasks, suggest that the proposed entropy indices provide instantaneous tracking of the heartbeat complexity, also allowing for the definition of complexity variability indices.

  13. Robust model-based analysis of single-particle tracking experiments with Spot-On.

    Science.gov (United States)

    Hansen, Anders S; Woringer, Maxime; Grimm, Jonathan B; Lavis, Luke D; Tjian, Robert; Darzacq, Xavier

    2018-01-04

    Single-particle tracking (SPT) has become an important method to bridge biochemistry and cell biology since it allows direct observation of protein binding and diffusion dynamics in live cells. However, accurately inferring information from SPT studies is challenging due to biases in both data analysis and experimental design. To address analysis bias, we introduce 'Spot-On', an intuitive web-interface. Spot-On implements a kinetic modeling framework that accounts for known biases, including molecules moving out-of-focus, and robustly infers diffusion constants and subpopulations from pooled single-molecule trajectories. To minimize inherent experimental biases, we implement and validate stroboscopic photo-activation SPT (spaSPT), which minimizes motion-blur bias and tracking errors. We validate Spot-On using experimentally realistic simulations and show that Spot-On outperforms other methods. We then apply Spot-On to spaSPT data from live mammalian cells spanning a wide range of nuclear dynamics and demonstrate that Spot-On consistently and robustly infers subpopulation fractions and diffusion constants. © 2018, Hansen et al.

  14. Real Time Tracking of Magmatic Intrusions by means of Ground Deformation Modeling during Volcanic Crises

    Science.gov (United States)

    Cannavò, Flavio; Camacho, Antonio G.; González, Pablo J.; Mattia, Mario; Puglisi, Giuseppe; Fernández, José

    2015-01-01

    Volcano observatories provide near real-time information and, ultimately, forecasts about volcano activity. For this reason, multiple physical and chemical parameters are continuously monitored. Here, we present a new method to efficiently estimate the location and evolution of magmatic sources based on a stream of real-time surface deformation data, such as High-Rate GPS, and a free-geometry magmatic source model. The tool allows tracking inflation and deflation sources in time, providing estimates of where a volcano might erupt, which is important in understanding an on-going crisis. We show a successful simulated application to the pre-eruptive period of May 2008, at Mount Etna (Italy). The proposed methodology is able to track the fast dynamics of the magma migration by inverting the real-time data within seconds. This general method is suitable for integration in any volcano observatory. The method provides first order unsupervised and realistic estimates of the locations of magmatic sources and of potential eruption sites, information that is especially important for civil protection purposes. PMID:26055494

  15. Identifying the origin of waterbird carcasses in Lake Michigan using a neural network source tracking model

    Science.gov (United States)

    Kenow, Kevin P.; Ge, Zhongfu; Fara, Luke J.; Houdek, Steven C.; Lubinski, Brian R.

    2016-01-01

    Avian botulism type E is responsible for extensive waterbird mortality on the Great Lakes, yet the actual site of toxin exposure remains unclear. Beached carcasses are often used to describe the spatial aspects of botulism mortality outbreaks, but lack specificity of offshore toxin source locations. We detail methodology for developing a neural network model used for predicting waterbird carcass motions in response to wind, wave, and current forcing, in lieu of a complex analytical relationship. This empirically trained model uses current velocity, wind velocity, significant wave height, and wave peak period in Lake Michigan simulated by the Great Lakes Coastal Forecasting System. A detailed procedure is further developed to use the model for back-tracing waterbird carcasses found on beaches in various parts of Lake Michigan, which was validated using drift data for radiomarked common loon (Gavia immer) carcasses deployed at a variety of locations in northern Lake Michigan during September and October of 2013. The back-tracing model was further used on 22 non-radiomarked common loon carcasses found along the shoreline of northern Lake Michigan in October and November of 2012. The model-estimated origins of those cases pointed to some common source locations offshore that coincide with concentrations of common loons observed during aerial surveys. The neural network source tracking model provides a promising approach for identifying locations of botulinum neurotoxin type E intoxication and, in turn, contributes to developing an understanding of the dynamics of toxin production and possible trophic transfer pathways.

  16. Investigating the Influence of Auxiliary Rails on Dynamic Behavior of Railway Transition Zone by a 3D Train-Track Interaction Model

    Directory of Open Access Journals (Sweden)

    H. Heydari-Noghabi

    Full Text Available Abstract Abrupt track vertical stiffness variations along railway tracks can lead to increased dynamic loads, asymmetric deformations, damaged track components, and consequently, increased maintenance costs. The junction of slab track and ballasted track is one of the existing areas where vertical track stiffness can suddenly change, therefore requiring a transition zone that smoothes the track stiffness change. One of the methods for constructing the transition zone at the junction of slab and ballasted tracks is to install auxiliary rails along the transition zone. In the present study, the dynamic behavior of this type of transition zone was evaluated by a train-track interaction model. For this purpose, a 3D model of the railway track was made, representing the slab track, the transition zone, and the ballasted track. Then, the modeling results were validated by the results of field tests. Afterwards, in order to study the dynamic behavior of the transition zone with auxiliary rails, different sensitive analyses, such as vehicle speed, vehicle load, number of auxiliary rails and railpad stiffness, were performed with the model. The obtained results showed that the use of auxiliary rails reduced the rail deflection variations along the transition zone from 35% to 28% for low and medium speeds (120, 160, 200 km/h, and from 40% to 33% for high speeds (250, 300 km/h.

  17. Tracking Skill Acquisition with Cognitive Diagnosis Models: A Higher-Order, Hidden Markov Model with Covariates

    Science.gov (United States)

    Wang, Shiyu; Yang, Yan; Culpepper, Steven Andrew; Douglas, Jeffrey A.

    2018-01-01

    A family of learning models that integrates a cognitive diagnostic model and a higher-order, hidden Markov model in one framework is proposed. This new framework includes covariates to model skill transition in the learning environment. A Bayesian formulation is adopted to estimate parameters from a learning model. The developed methods are…

  18. A Real-Time Model-Based Human Motion Tracking and Analysis for Human-Computer Interface Systems

    Directory of Open Access Journals (Sweden)

    Chung-Lin Huang

    2004-09-01

    Full Text Available This paper introduces a real-time model-based human motion tracking and analysis method for human computer interface (HCI. This method tracks and analyzes the human motion from two orthogonal views without using any markers. The motion parameters are estimated by pattern matching between the extracted human silhouette and the human model. First, the human silhouette is extracted and then the body definition parameters (BDPs can be obtained. Second, the body animation parameters (BAPs are estimated by a hierarchical tritree overlapping searching algorithm. To verify the performance of our method, we demonstrate different human posture sequences and use hidden Markov model (HMM for posture recognition testing.

  19. An Integral Model for Target Tracking Based on the Use of a WSN

    Directory of Open Access Journals (Sweden)

    Pietro Manzoni

    2013-06-01

    Full Text Available The use of wireless sensor networks (WSN in tracking applications is growing at a fast pace. In these applications, the sensor nodes discover, monitor and track an event or target object. A significant number of proposals relating the use of WSNs for target tracking have been published to date. However, they either focus on the tracking algorithm or on the communication protocol, and none of them address the problem integrally. In this paper, a comprehensive proposal for target detection and tracking is discussed. We introduce a tracking algorithm to detect and estimate a target location. Moreover, we introduce a low-overhead routing protocol to be used along with our tracking algorithm. The proposed algorithm has low computational complexity and has been designed considering the use of a mobile sink while generating minimal delay and packet loss. We also discuss the results of the evaluation of the proposed algorithms.

  20. Embedded Analytical Solutions Improve Accuracy in Convolution-Based Particle Tracking Models using Python

    Science.gov (United States)

    Starn, J. J.

    2013-12-01

    Particle tracking often is used to generate particle-age distributions that are used as impulse-response functions in convolution. A typical application is to produce groundwater solute breakthrough curves (BTC) at endpoint receptors such as pumping wells or streams. The commonly used semi-analytical particle-tracking algorithm based on the assumption of linear velocity gradients between opposing cell faces is computationally very fast when used in combination with finite-difference models. However, large gradients near pumping wells in regional-scale groundwater-flow models often are not well represented because of cell-size limitations. This leads to inaccurate velocity fields, especially at weak sinks. Accurate analytical solutions for velocity near a pumping well are available, and various boundary conditions can be imposed using image-well theory. Python can be used to embed these solutions into existing semi-analytical particle-tracking codes, thereby maintaining the integrity and quality-assurance of the existing code. Python (and associated scientific computational packages NumPy, SciPy, and Matplotlib) is an effective tool because of its wide ranging capability. Python text processing allows complex and database-like manipulation of model input and output files, including binary and HDF5 files. High-level functions in the language include ODE solvers to solve first-order particle-location ODEs, Gaussian kernel density estimation to compute smooth particle-age distributions, and convolution. The highly vectorized nature of NumPy arrays and functions minimizes the need for computationally expensive loops. A modular Python code base has been developed to compute BTCs using embedded analytical solutions at pumping wells based on an existing well-documented finite-difference groundwater-flow simulation code (MODFLOW) and a semi-analytical particle-tracking code (MODPATH). The Python code base is tested by comparing BTCs with highly discretized synthetic steady

  1. Epipolar Resampling of Cross-Track Pushbroom Satellite Imagery Using the Rigorous Sensor Model

    Directory of Open Access Journals (Sweden)

    Mojtaba Jannati

    2017-01-01

    Full Text Available Epipolar resampling aims to eliminate the vertical parallax of stereo images. Due to the dynamic nature of the exterior orientation parameters of linear pushbroom satellite imagery and the complexity of reconstructing the epipolar geometry using rigorous sensor models, so far, no epipolar resampling approach has been proposed based on these models. In this paper for the first time it is shown that the orientation of the instantaneous baseline (IB of conjugate image points (CIPs in the linear pushbroom satellite imagery can be modeled with high precision in terms of the rows- and the columns-number of CIPs. Taking advantage of this feature, a novel approach is then presented for epipolar resampling of cross-track linear pushbroom satellite imagery. The proposed method is based on the rigorous sensor model. As the instantaneous position of sensors remains fixed, the digital elevation model of the area of interest is not required in the resampling process. Experimental results obtained from two pairs of SPOT and one pair of RapidEye stereo imagery with different terrain conditions shows that the proposed epipolar resampling approach benefits from a superior accuracy, as the remained vertical parallaxes of all CIPs in the normalized images are close to zero.

  2. Development of internal models and predictive abilities for visual tracking during childhood.

    Science.gov (United States)

    Ego, Caroline; Yüksel, Demet; Orban de Xivry, Jean-Jacques; Lefèvre, Philippe

    2016-01-01

    The prediction of the consequences of our own actions through internal models is an essential component of motor control. Previous studies showed improvement of anticipatory behaviors with age for grasping, drawing, and postural control. Since these actions require visual and proprioceptive feedback, these improvements might reflect both the development of internal models and the feedback control. In contrast, visual tracking of a temporarily invisible target gives specific markers of prediction and internal models for eye movements. Therefore, we recorded eye movements in 50 children (aged 5-19 yr) and in 10 adults, who were asked to pursue a visual target that is temporarily blanked. Results show that the youngest children (5-7 yr) have a general oculomotor behavior in this task, qualitatively similar to the one observed in adults. However, the overall performance of older subjects in terms of accuracy at target reappearance and variability in their behavior was much better than the youngest children. This late maturation of predictive mechanisms with age was reflected into the development of the accuracy of the internal models governing the synergy between the saccadic and pursuit systems with age. Altogether, we hypothesize that the maturation of the interaction between smooth pursuit and saccades that relies on internal models of the eye and target displacement is related to the continuous maturation of the cerebellum. Copyright © 2016 the American Physiological Society.

  3. Extended Cann Model for Behavioral Modeling of Envelope Tracking Power Amplifiers

    DEFF Research Database (Denmark)

    Tafuri, Felice Francesco; Larsen, Torben

    2013-01-01

    extending the well-known Cann model. The Cann model is extended including the modulated supply voltage Venv as a new independent variable, enhancing the AM/AM model so that it can mimic PA memory effects and defining a dynamic nonlinear AM/PM function that can model the phase distortions introduced...

  4. Amorphous calcium carbonate particles form coral skeletons

    Science.gov (United States)

    Mass, Tali; Giuffre, Anthony J.; Sun, Chang-Yu; Stifler, Cayla A.; Frazier, Matthew J.; Neder, Maayan; Tamura, Nobumichi; Stan, Camelia V.; Marcus, Matthew A.; Gilbert, Pupa U. P. A.

    2017-09-01

    Do corals form their skeletons by precipitation from solution or by attachment of amorphous precursor particles as observed in other minerals and biominerals? The classical model assumes precipitation in contrast with observed “vital effects,” that is, deviations from elemental and isotopic compositions at thermodynamic equilibrium. Here, we show direct spectromicroscopy evidence in Stylophora pistillata corals that two amorphous precursors exist, one hydrated and one anhydrous amorphous calcium carbonate (ACC); that these are formed in the tissue as 400-nm particles; and that they attach to the surface of coral skeletons, remain amorphous for hours, and finally, crystallize into aragonite (CaCO3). We show in both coral and synthetic aragonite spherulites that crystal growth by attachment of ACC particles is more than 100 times faster than ion-by-ion growth from solution. Fast growth provides a distinct physiological advantage to corals in the rigors of the reef, a crowded and fiercely competitive ecosystem. Corals are affected by warming-induced bleaching and postmortem dissolution, but the finding here that ACC particles are formed inside tissue may make coral skeleton formation less susceptible to ocean acidification than previously assumed. If this is how other corals form their skeletons, perhaps this is how a few corals survived past CO2 increases, such as the Paleocene-Eocene Thermal Maximum that occurred 56 Mya.

  5. Reporter systems for in vivo tracking of lactic acid bacteria in animal model studies

    Science.gov (United States)

    van Zyl, Winschau F; Deane, Shelly M; Dicks, Leon M T

    2015-01-01

    Bioluminescence (BLI) and fluorescence imaging (FI) allow for non-invasive detection of viable microorganisms from within living tissue and are thus ideally suited for in vivo probiotic studies. Highly sensitive optical imaging techniques detect signals from the excitation of fluorescent proteins, or luciferase-catalyzed oxidation reactions. The excellent relation between microbial numbers and photon emission allow for quantification of tagged bacteria in vivo with extreme accuracy. More information is gained over a shorter period compared to traditional pre-clinical animal studies. The review summarizes the latest advances in in vivo bioluminescence and fluorescence imaging and points out the advantages and limitations of different techniques. The practical application of BLI and FI in the tracking of lactic acid bacteria in animal models is addressed. PMID:26516656

  6. Tracking and Analysis Framework (TAF) model documentation and user`s guide

    Energy Technology Data Exchange (ETDEWEB)

    Bloyd, C.; Camp, J.; Conzelmann, G. [and others

    1996-12-01

    With passage of the 1990 Clean Air Act Amendments, the United States embarked on a policy for controlling acid deposition that has been estimated to cost at least $2 billion. Title IV of the Act created a major innovation in environmental regulation by introducing market-based incentives - specifically, by allowing electric utility companies to trade allowances to emit sulfur dioxide (SO{sub 2}). The National Acid Precipitation Assessment Program (NAPAP) has been tasked by Congress to assess what Senator Moynihan has termed this {open_quotes}grand experiment.{close_quotes} Such a comprehensive assessment of the economic and environmental effects of this legislation has been a major challenge. To help NAPAP face this challenge, the U.S. Department of Energy (DOE) has sponsored development of an integrated assessment model, known as the Tracking and Analysis Framework (TAF). This section summarizes TAF`s objectives and its overall design.

  7. Tracking Control of A Balancing Robot – A Model-Based Approach

    Directory of Open Access Journals (Sweden)

    Zaiczek Tobias

    2014-08-01

    Full Text Available This paper presents a control concept for a single-axle mobile robot moving on the horizontal plane. A mathematical model of the nonholonomic mechanical system is derived using Hamel's equations of motion. Subsequently, a concept for a tracking controller is described in detail. This controller keeps the mobile robot on a given reference trajectory while maintaining it in an upright position. The control objective is reached by a cascade control structure. By an appropriate input transformation, we are able to utilize an input-output linearization of a subsystem. For the remaining dynamics a linear set-point control law is presented. Finally, the performance of the implemented control law is illustrated by simulation results.

  8. In vivo tracking of stem cells labeled with a nanoparticle in Alzheimer's disease animal model

    Science.gov (United States)

    Ha, Sungji; Suh, Yoo-Hun; Chang, Keun-A.

    2013-05-01

    Stem cell therapy is a promising tool for the treatment of diverse conditions including neurodegenerative diseases. To understand transplanted stem cell biology, in vivo imaging is necessary. Nano material has great potential for in vivo imaging and several noninvasive methods are used such as magnetic resonance imaging (MRI), positron emission tomography (PET), Fluorescence imaging (FI) and Near-infrared fluorescence imaging (NIRFI). However, each method has limitations for in vivo imaging. To overcome these limitations, multimodal nanoprobes have been developed. In the present study, we intravenously injected human adipose derived stem cells (hASCs) that labeled with multimodal nano particle, LEO-LIVETM-Magnoxide 797 or 675, into the Tg2576 mice, Alzheimer's disease (AD) mouse model. Sequential in vivo tracking was performed with mice injected with hASCs. We could found fluorescence signals until 10 days after injection.

  9. Model-based identification of motion sensor placement for tracking retraction and elongation of the tongue.

    Science.gov (United States)

    Wang, Yikun K; Nash, Martyn P; Pullan, Andrew J; Kieser, Jules A; Röhrle, Oliver

    2013-04-01

    Electromagnetic articulography (EMA) is designed to track facial and tongue movements. In practice, the EMA sensors for tracking the movement of the tongue's surface are placed heuristically. No recommendation exists. Within this paper, a model-based approach providing a mathematical analysis and a computational-based recommendation for the placement of sensors, which is based on the tongue's envelope of movement, is proposed. For this purpose, an anatomically detailed Finite Element (FE) model of the tongue has been employed to determine the envelope of motion for retraction and elongation using a forward simulation. Two optimality criteria have been proposed to identify a set of optimal sensor locations based on the pre-computed envelope of motion. The first one is based on the assumption that locations exhibiting large displacements contain the most information regarding the tongue's movement and are less susceptible to measurement errors. The second one selects sensors exhibiting each the largest displacements in the anterior-posterior, superior-inferior, medial-lateral and overall direction. The quality of the two optimality criteria is analysed based on their ability to deduce from the respective sensor locations the corresponding muscle activation parameters of the relevant muscle fibre groups during retraction and elongation by solving the corresponding inverse problem. For this purpose, a statistical analysis has been carried out, in which sensor locations for two different modes of deformation have been subjected to typical measurement errors. Then, for tongue retraction and elongation, the expectation value, the standard deviation, the averaged bias and the averaged coefficient of variation have been computed based on 41 different error-afflicted sensor locations. The results show that the first optimality criteria is superior to the second one and that the averaged bias and averaged coefficient of variation decrease when the number of sensors is

  10. Mass extinction spectra and size distribution measurements of quartz and amorphous silica aerosol at 0.33-19 μm compared to modelled extinction using Mie, CDE, and T-matrix theories

    Science.gov (United States)

    Reed, Benjamin E.; Peters, Daniel M.; McPheat, Robert; Smith, Andrew J. A.; Grainger, R. G.

    2017-09-01

    Simultaneous measurements were made of the spectral extinction (from 0.33-19 μm) and particle size distribution of silica aerosol dispersed in nitrogen gas. Two optical systems were used to measure the extinction spectra over a wide spectral range: a Fourier transform spectrometer in the infrared and two diffraction grating spectrometers covering visible and ultraviolet wavelengths. The particle size distribution was measured using a scanning mobility particle sizer and an optical particle counter. The measurements were applied to one amorphous and two crsystalline silica (quartz) samples. In the infrared peak values of the mass extinction coefficient (MEC) of the crystalline samples were 1.63 ± 0.23 m2g-1 at 9.06 μm and 1.53 ± 0.26 m2g-1 at 9.14 μm with corresponding effective radii of 0.267 and 0.331 μm, respectively. For the amorphous sample the peak MEC value was 1.37 ± 0.18 m2g-1 at 8.98 μm and the effective radius of the particles was 0.374 μm. Using the measured size distribution and literature values of the complex refractive index as inputs, three scattering models were evaluated for modelling the extinction: Mie theory, the Rayleigh continuous distribution of ellipsoids (CDE) model, and T-matrix modelling of a distribution of spheroids. Mie theory provided poor fits to the infrared extinction of quartz (R2 0.82 for crsytalline sillica and R2 = 0.98 for amorphous silica. The T-matrix approach was able to fit the amorphous infrared extinction data with an R2 value of 0.995. Allowing for the possibility of reduced crystallinity in the milled crystal samples, using a mixture of amorphous and crystalline T-matrix cross-sections provided fits with R2 values greater than 0.97 for the infrared extinction of the crystalline samples.

  11. Monte Carlo Simulation of Random-Anisotropy Amorphous Magnets

    Science.gov (United States)

    Bondarev, A. V.; Bataronov, I. L.

    2018-01-01

    Using the Monte Carlo method, within the frame of the Heisenberg model, we studies the magnetic properties of amorphous Tb. The relaxation of magnetization of the model of amorphous Tb was studied. We stablished that the relaxation goes in two stages. On the first stage the magnetization sharply decreases by some amount ΔMz , on the second stage the magnetization decreases with time according to the logarithmic law. The possible mechanisms of relaxation is discussed.

  12. Model-Free Primitive-Based Iterative Learning Control Approach to Trajectory Tracking of MIMO Systems With Experimental Validation.

    Science.gov (United States)

    Radac, Mircea-Bogdan; Precup, Radu-Emil; Petriu, Emil M

    2015-11-01

    This paper proposes a novel model-free trajectory tracking of multiple-input multiple-output (MIMO) systems by the combination of iterative learning control (ILC) and primitives. The optimal trajectory tracking solution is obtained in terms of previously learned solutions to simple tasks called primitives. The library of primitives that are stored in memory consists of pairs of reference input/controlled output signals. The reference input primitives are optimized in a model-free ILC framework without using knowledge of the controlled process. The guaranteed convergence of the learning scheme is built upon a model-free virtual reference feedback tuning design of the feedback decoupling controller. Each new complex trajectory to be tracked is decomposed into the output primitives regarded as basis functions. The optimal reference input for the control system to track the desired trajectory is next recomposed from the reference input primitives. This is advantageous because the optimal reference input is computed straightforward without the need to learn from repeated executions of the tracking task. In addition, the optimization problem specific to trajectory tracking of square MIMO systems is decomposed in a set of optimization problems assigned to each separate single-input single-output control channel that ensures a convenient model-free decoupling. The new model-free primitive-based ILC approach is capable of planning, reasoning, and learning. A case study dealing with the model-free control tuning for a nonlinear aerodynamic system is included to validate the new approach. The experimental results are given.

  13. Implementing the Serial Number Tracking model in telecommunications: a case study of Croatia

    Directory of Open Access Journals (Sweden)

    Neven Polovina

    2012-01-01

    Full Text Available Background: The case study describes the implementation of the SNT (Serial Number Tracking model in an integrated information system, as a means of business support in a Croatian mobile telecommunications company. Objectives: The goal was to show how to make the best practice of the SNT implementation in the telecommunication industry, with referencing to problems which have arisen during the implementation. Methods/Approach: the case study approach was used based on the documentation about the SNT model and the business intelligence system in the Croatian mobile telecommunications company. Results: Economic aspects of the effectiveness of the SNT model are described and confirmed based on actual tangible and predominantly on intangible benefits. Conclusions: Advantages of the SNT model are multiple: operating costs for storage and transit of goods were reduced, accuracy of deliveries and physical inventory was improved; a new source of information for the business intelligence system was obtained; operating processes in the distribution of goods were advanced; transit insurance costs decreased and there were fewer cases of fraudulent behaviour.

  14. Multidimensional Taylor Network Optimal Control of MIMO Nonlinear Systems without Models for Tracking by Output Feedback

    Directory of Open Access Journals (Sweden)

    Qi-Ming Sun

    2017-01-01

    Full Text Available The actual controlled objects are generally multi-input and multioutput (MIMO nonlinear systems with imprecise models or even without models, so it is one of the hot topics in the control theory. Due to the complex internal structure, the general control methods without models tend to be based on neural networks. However, the neuron of neural networks includes the exponential function, which contributes to the complexity of calculation, making the neural network control unable to meet the real-time requirements. The newly developed multidimensional Taylor network (MTN requires only addition and multiplication, so it is easy to realize real-time control. In the present study, the MTN approach is extended to MIMO nonlinear systems without models to realize adaptive output feedback control. The MTN controller is proposed to guarantee the stability of the closed-loop system. Our experimental results show that the output signals of the system are bounded and the tracking error goes nearly to zero. The MTN optimal controller is proven to promise far better real-time dynamic performance and robustness than the BP neural network self-adaption reconstitution controller.

  15. Modeling and Predistortion of Envelope Tracking Power Amplifiers using a Memory Binomial Model

    DEFF Research Database (Denmark)

    Tafuri, Felice Francesco; Sira, Daniel; Larsen, Torben

    2013-01-01

    . The model definition is based on binomial series, hence the name of memory binomial model (MBM). The MBM is here applied to measured data-sets acquired from an ET measurement set-up. When used as a PA model the MBM showed an NMSE (Normalized Mean Squared Error) as low as −40dB and an ACEPR (Adjacent Channel...

  16. Cyclone-track based seasonal prediction for South Pacific tropical cyclone activity using APCC multi-model ensemble prediction

    Science.gov (United States)

    Kim, Ok-Yeon; Chan, Johnny C. L.

    2018-01-01

    This study aims to predict the seasonal TC track density over the South Pacific by combining the Asia-Pacific Economic Cooperation (APEC) Climate Center (APCC) multi-model ensemble (MME) dynamical prediction system with a statistical model. The hybrid dynamical-statistical model is developed for each of the three clusters that represent major groups of TC best tracks in the South Pacific. The cross validation result from the MME hybrid model demonstrates moderate but statistically significant skills to predict TC numbers across all TC clusters, with correlation coefficients of 0.4 to 0.6 between the hindcasts and observations for 1982/1983 to 2008/2009. The prediction skill in the area east of about 170°E is significantly influenced by strong El Niño, whereas the skill in the southwest Pacific region mainly comes from the linear trend of TC number. The prediction skill of TC track density is particularly high in the region where there is climatological high TC track density around the area 160°E-180° and 20°S. Since this area has a mixed response with respect to ENSO, the prediction skill of TC track density is higher in non-ENSO years compared to that in ENSO years. Even though the cross-validation prediction skill is higher in the area east of about 170°E compared to other areas, this region shows less skill for track density based on the categorical verification due to huge influences by strong El Niño years. While prediction skill of the developed methodology varies across the region, it is important that the model demonstrates skill in the area where TC activity is high. Such a result has an important practical implication—improving the accuracy of seasonal forecast and providing communities at risk with advanced information which could assist with preparedness and disaster risk reduction.

  17. Molecular dynamics simulation of ion-beam-amorphization of Si, Ge and GaAs

    CERN Document Server

    Nord, J D; Keinonen, J

    2002-01-01

    We use molecular dynamics simulations to study ion-irradiation-induced amorphization in Si, Ge and GaAs using several different interatomic force models. We find that the coordination number is higher, and the average bond length longer, for the irradiated amorphous structures than for the molten ones in Si and Ge. For amorphous GaAs, we suggest that longer Ga-Ga bonds, also present in pure Ga, are produced during the irradiation. In Si the amorphization is found to proceed via growth of amorphous regions, and low energy recoils are found to induce athermal recrystallization during irradiation.

  18. Variation that can be expected when using particle tracking models in connectivity studies

    Science.gov (United States)

    Hufnagl, Marc; Payne, Mark; Lacroix, Geneviève; Bolle, Loes J.; Daewel, Ute; Dickey-Collas, Mark; Gerkema, Theo; Huret, Martin; Janssen, Frank; Kreus, Markus; Pätsch, Johannes; Pohlmann, Thomas; Ruardij, Piet; Schrum, Corinna; Skogen, Morten D.; Tiessen, Meinard C. H.; Petitgas, Pierre; van Beek, Jan K. L.; van der Veer, Henk W.; Callies, Ulrich

    2017-09-01

    Hydrodynamic Ocean Circulation Models and Lagrangian particle tracking models are valuable tools e.g. in coastal ecology to identify the connectivity between offshore spawning and coastal nursery areas of commercially important fish, for risk assessment and more for defining or evaluating marine protected areas. Most studies are based on only one model and do not provide levels of uncertainty. Here this uncertainty was addressed by applying a suite of 11 North Sea models to test what variability can be expected concerning connectivity. Different notional test cases were calculated related to three important and well-studied North Sea fish species: herring (Clupea harengus), and the flatfishes sole (Solea solea) and plaice (Pleuronectes platessa). For sole and plaice we determined which fraction of particles released in the respective spawning areas would reach a coastal marine protected area. For herring we determined the fraction located in a wind park after a predefined time span. As temperature is more and more a focus especially in biological and global change studies, furthermore inter-model variability in temperatures experienced by the virtual particles was determined. The main focus was on the transport variability originating from the physical models and thus biological behavior was not included. Depending on the scenario, median experienced temperatures differed by 3 °C between years. The range between the different models in one year was comparable to this temperature range observed between modelled years. Connectivity between flatfish spawning areas and the coastal protected area was highly dependent on the release location and spawning time. No particles released in the English Channel in the sole scenario reached the protected area while up to 20% of the particles released in the plaice scenario did. Interannual trends in transport directions and connectivity rates were comparable between models but absolute values displayed high variations. Most

  19. Tracking objects with fixed-wing UAV using model predictive control and machine vision

    OpenAIRE

    Skjong, Espen; Nundal, Stian Aas

    2014-01-01

    This thesis describes the development of an object tracking system for unmanned aerial vehicles (UAVs), intended to be used for search and rescue (SAR) missions. The UAV is equipped with a two-axis gimbal system, which houses an infrared (IR) camera used to detect and track objects of interest, and a lower level autopilot. An external computer vision (CV) module is assumed implemented and connected to the object tracking system, providing object positions and velocities to the control system....

  20. Linear Mathematical Model for Seam Tracking with an Arc Sensor in P-GMAW Processes.

    Science.gov (United States)

    Liu, Wenji; Li, Liangyu; Hong, Ying; Yue, Jianfeng

    2017-03-14

    Arc sensors have been used in seam tracking and widely studied since the 80s and commercial arc sensing products for T and V shaped grooves have been developed. However, it is difficult to use these arc sensors in narrow gap welding because the arc stability and sensing accuracy are not satisfactory. Pulse gas melting arc welding (P-GMAW) has been successfully applied in narrow gap welding and all position welding processes, so it is worthwhile to research P-GMAW arc sensing technology. In this paper, we derived a linear mathematical P-GMAW model for arc sensing, and the assumptions for the model are verified through experiments and finite element methods. Finally, the linear characteristics of the mathematical model were investigated. In torch height changing experiments, uphill experiments, and groove angle changing experiments the P-GMAW arc signals all satisfied the linear rules. In addition, the faster the welding speed, the higher the arc signal sensitivities; the smaller the groove angle, the greater the arc sensitivities. The arc signal variation rate needs to be modified according to the welding power, groove angles, and weaving or rotate speed.

  1. A Low-Cost Maximum Power Point Tracking System Based on Neural Network Inverse Model Controller

    Directory of Open Access Journals (Sweden)

    Carlos Robles Algarín

    2018-01-01

    Full Text Available This work presents the design, modeling, and implementation of a neural network inverse model controller for tracking the maximum power point of a photovoltaic (PV module. A nonlinear autoregressive network with exogenous inputs (NARX was implemented in a serial-parallel architecture. The PV module mathematical modeling was developed, a buck converter was designed to operate in the continuous conduction mode with a switching frequency of 20 KHz, and the dynamic neural controller was designed using the Neural Network Toolbox from Matlab/Simulink (MathWorks, Natick, MA, USA, and it was implemented on an open-hardware Arduino Mega board. To obtain the reference signals for the NARX and determine the 65 W PV module behavior, a system made of a 0.8 W PV cell, a temperature sensor, a voltage sensor and a static neural network, was used. To evaluate performance a comparison with the P&O traditional algorithm was done in terms of response time and oscillations around the operating point. Simulation results demonstrated the superiority of neural controller over the P&O. Implementation results showed that approximately the same power is obtained with both controllers, but the P&O controller presents oscillations between 7 W and 10 W, in contrast to the inverse controller, which had oscillations between 1 W and 2 W.

  2. Modeling Bimolecular Reactions and Transport in Porous Media Via Particle Tracking

    Energy Technology Data Exchange (ETDEWEB)

    Dong Ding; David Benson; Amir Paster; Diogo Bolster

    2012-01-01

    We use a particle-tracking method to simulate several one-dimensional bimolecular reactive transport experiments. In this numerical method, the reactants are represented by particles: advection and dispersion dominate the flow, and molecular diffusion dictates, in large part, the reactions. The particle/particle reactions are determined by a combination of two probabilities dictated by the physics of transport and energetics of reaction. The first is that reactant particles occupy the same volume over a short time interval. The second is the conditional probability that two collocated particles favorably transform into a reaction. The first probability is a direct physical representation of the degree of mixing in an advancing displacement front, and as such lacks empirical parameters except for the user-defined number of particles. This number can be determined analytically from concentration autocovariance, if this type of data is available. The simulations compare favorably to two physical experiments. In one, the concentration of product, 1,2-naphthoquinoe-4-aminobenzene (NQAB) from reaction between 1,2-naphthoquinone-4-sulfonic acid (NQS) and aniline (AN), was measured at the outflow of a column filled with glass beads at different times. In the other, the concentration distribution of reactants (CuSO_4 and EDTA^{4-}) and products (CuEDTA^{4-}) were quantified by snapshots of transmitted light through a column packed with cryloite sand. The thermodynamic rate coefficient in the latter experiment was 10^7 times greater than the former experiment, making it essentially instantaneous. When compared to the solution of the advection-dispersion-reaction equation (ADRE) with the well-mixed reaction coefficient, the experiments and the particle-tracking simulations showed on the order of 20% to 40% less overall product, which is attributed to poor mixing. The poor mixing also leads to higher product concentrations on the edges of the mixing zones, which the particle

  3. Comparison between Einstein and Debye models for an amorphous Ni46Ti54 alloy produced by mechanical alloying investigated using extended x-ray absorption fine structure and cumulant expansion.

    Science.gov (United States)

    Machado, K D

    2011-02-14

    We investigated an amorphous Ni(46)Ti(54) alloy produced by mechanical alloying using extended x-ray absorption fine structure (EXAFS) technique and cumulant expansion considering Einstein and Debye models for the temperature dependence of the cumulants. Results obtained from both models were compared and very similar values were obtained. From them, we found information about the structure of the alloy besides thermal and structural disorder, anharmonicity, thermal expansion, and asymmetry of the partial distribution functions g(ij)(r). The cumulants C(1)(*), C(2)(*), and C(3)(*) also allowed us to reconstruct the g(ij)(r, T) functions from EXAFS.

  4. Slab track

    OpenAIRE

    Golob, Tina

    2014-01-01

    The last 160 years has been mostly used conventional track with ballasted bed, sleepers and steel rail. Ensuring the high speed rail traffic, increasing railway track capacities, providing comfortable and safe ride as well as high reliability and availability railway track, has led to development of innovative systems for railway track. The so-called slab track was first built in 1972 and since then, they have developed many different slab track systems around the world. Slab track was also b...

  5. Track structure based modelling of light ion radiation effects on nuclear and mitochondrial DNA

    Science.gov (United States)

    Schmitt, Elke; Ottolenghi, Andrea; Dingfelder, Michael; Friedland, Werner; Kundrat, Pavel; Baiocco, Giorgio

    2016-07-01

    Space radiation risk assessment is of great importance for manned spaceflights in order to estimate risks and to develop counter-measures to reduce them. Biophysical simulations with PARTRAC can help greatly to improve the understanding of initial biological response to ionizing radiation. Results from modelling radiation quality dependent DNA damage and repair mechanisms up to chromosomal aberrations (e.g. dicentrics) can be used to predict radiation effects depending on the kind of mixed radiation field exposure. Especially dicentric yields can serve as a biomarker for an increased risk due to radiation and hence as an indicator for the effectiveness of the used shielding. PARTRAC [1] is a multi-scale biophysical research MC code for track structure based initial DNA damage and damage response modelling. It integrates physics, radiochemistry, detailed nuclear DNA structure and molecular biology of DNA repair by NHEJ-pathway to assess radiation effects on cellular level [2]. Ongoing experiments with quasi-homogeneously distributed compared to sub-micrometre focused bunches of protons, lithium and carbon ions allow a separation of effects due to DNA damage complexity on nanometre scale from damage clustering on (sub-) micrometre scale [3, 4]. These data provide an unprecedented benchmark for the DNA damage response model in PARTRAC and help understand the mechanisms leading to cell killing and chromosomal aberrations (e.g. dicentrics) induction. A large part of space radiation is due to a mixed ion field of high energy protons and few heavier ions that can be only partly absorbed by the shielding. Radiation damage induced by low-energy ions significantly contributes to the high relative biological efficiency (RBE) of ion beams around Bragg peak regions. For slow light ions the physical cross section data basis in PARTRAC has been extended to investigate radiation quality effects in the Bragg peak region [5]. The resulting range and LET values agree with ICRU data

  6. Structural observation of amorphous alloys by neutron diffraction

    International Nuclear Information System (INIS)

    Fukunaga, Toshiharu; Itoh, Keiji

    2006-01-01

    Neutron diffraction is a powerful tool to elucidate the atomic arrangement of amorphous alloys because of characteristic scattering lengths of constituent elements. For hydrogen absorption amorphous alloys H/D isotopic substitution was employed to observe the location of deuterium atoms because the neutron coherent scattering length of deuterium is large enough to observe in comparison with those of the constituent atoms. Moreover, Reverse Monte Carlo (RMC) modeling has been recognized to be an excellent method for visualizing the three-dimensional atomic arrangement of amorphous alloys, based on the results of neutron and X-ray diffraction experiments. Therefore, the combination of neutron, X-ray diffraction experiments and the RMC modeling was used to clarify the topological characteristics of the structure of amorphous alloys. (author)

  7. Tracking Student Achievement in Music Performance: Developing Student Learning Objectives for Growth Model Assessments

    Science.gov (United States)

    Wesolowski, Brian C.

    2015-01-01

    Student achievement growth data are increasingly used for assessing teacher effectiveness and tracking student achievement in the classroom. Guided by the student learning objective (SLO) framework, music teachers are now responsible for collecting, tracking, and reporting student growth data. Often, the reported data do not accurately reflect the…

  8. Reduced-temperature crystallization of thin amorphous Fe80B20 films studied via empirical modeling of extended x-ray absorption fine structure

    Science.gov (United States)

    Harris, V. G.; Oliver, S. A.; Ayers, J. D.; Das, B. N.; Koon, N. C.

    1996-04-01

    The evolution of the local atomic environment around Fe atoms in very thin (15 nm), amorphous, partially crystallized and fully crystallized films of Fe80B20 was studied using extended x-ray absorption fine structure (EXAFS) measurements. The relative atomic fraction of each crystalline phase present in the annealed samples was extracted from the Fe EXAFS data by a least-squares fitting procedure, using data collected from t-Fe3B, t-Fe2B, and α-Fe standards. The type and relative fraction of the crystallization products follows the trends previously measured in Fe80B20 melt-spun ribbons, except for the fact that crystallization temperatures are ≊200 K lower than those measured in bulk equivalents. This greatly reduced crystallization temperature may arise from the dominant role of surface nucleation sites in the crystallization of very thin amorphous films.

  9. Geometry modeling of single track cladding deposited by high power diode laser with rectangular beam spot

    Science.gov (United States)

    Liu, Huaming; Qin, Xunpeng; Huang, Song; Hu, Zeqi; Ni, Mao

    2018-01-01

    This paper presents an investigation on the relationship between the process parameters and geometrical characteristics of the sectional profile for the single track cladding (STC) deposited by High Power Diode Laser (HPDL) with rectangle beam spot (RBS). To obtain the geometry parameters, namely cladding width Wc and height Hc of the sectional profile, a full factorial design (FFD) of experiment was used to conduct the experiments with a total of 27. The pre-placed powder technique has been employed during laser cladding. The influence of the process parameters including laser power, powder thickness and scanning speed on the Wc and Hc was analyzed in detail. A nonlinear fitting model was used to fit the relationship between the process parameters and geometry parameters. And a circular arc was adopted to describe the geometry profile of the cross-section of STC. The above models were confirmed by all the experiments. The results indicated that the geometrical characteristics of the sectional profile of STC can be described as the circular arc, and the other geometry parameters of the sectional profile can be calculated only using Wc and Hc. Meanwhile, the Wc and Hc can be predicted through the process parameters.

  10. Dynamic wake model with coordinated pitch and torque control of wind farms for power tracking

    Science.gov (United States)

    Shapiro, Carl; Meyers, Johan; Meneveau, Charles; Gayme, Dennice

    2017-11-01

    Control of wind farm power production, where wind turbines within a wind farm coordinate to follow a time-varying power set point, is vital for increasing renewable energy participation in the power grid. Previous work developed a one-dimensional convection-diffusion equation describing the advection of the velocity deficit behind each turbine (wake) as well the turbulent mixing of the wake with the surrounding fluid. Proof-of-concept simulations demonstrated that a receding horizon controller built around this time-dependent model can effectively provide power tracking services by modulating the thrust coefficients of individual wind turbines. In this work, we extend this model-based controller to include pitch angle and generator torque control and the first-order dynamics of the drive train. Including these dynamics allows us to investigate control strategies for providing kinetic energy reserves to the grid, i.e. storing kinetic energy from the wind in the rotating mass of the wind turbine rotor for later use. CS, CM, and DG are supported by NSF (ECCS-1230788, CMMI 1635430, and OISE-1243482, the WINDINSPIRE project). JM is supported by ERC (ActiveWindFarms, 306471). This research was conducted using computational resources at MARCC.

  11. Estimation of error components in a multi-error linear regression model, with an application to track fitting

    International Nuclear Information System (INIS)

    Fruehwirth, R.

    1993-01-01

    We present an estimation procedure of the error components in a linear regression model with multiple independent stochastic error contributions. After solving the general problem we apply the results to the estimation of the actual trajectory in track fitting with multiple scattering. (orig.)

  12. Mathematical pointing model establishment of the visual tracking theodolite for satellites in two kinds of observation methods.

    Science.gov (United States)

    Zhang, Yuncheng

    The mathematical pointing model is establishment of the visual tracking theodolite for satellites in two kinds of observation methods at Yunnan Observatory, which is related to the digitalisation reform and the optical-electronic technique reform, is introduced respectively in this paper.

  13. First test model of the optical microscope which images the whole vertical particle tracks without any depth scanning

    International Nuclear Information System (INIS)

    Soroko, L.M.

    2001-01-01

    The first test model of the optical microscope which produces the in focus image of the whole vertical particle track without depth scanning is described. The in focus image of the object consisting of the linear array of the point-like elements was obtained. A comparison with primary out of focus image of such an object has been made

  14. Information acquisition during online decision-making : A model-based exploration using eye-tracking data

    NARCIS (Netherlands)

    Shi, W.; Wedel, M.; Pieters, R.

    2013-01-01

    We propose a model of eye-tracking data to understand information acquisition patterns on attribute-by-product matrices, which are common in online choice environments such as comparison websites. The objective is to investigate how consumers gather product and attribute information from moment to

  15. Establishment and verification of three-dimensional dynamic model for heavy-haul train-track coupled system

    Science.gov (United States)

    Liu, Pengfei; Zhai, Wanming; Wang, Kaiyun

    2016-11-01

    For the long heavy-haul train, the basic principles of the inter-vehicle interaction and train-track dynamic interaction are analysed firstly. Based on the theories of train longitudinal dynamics and vehicle-track coupled dynamics, a three-dimensional (3-D) dynamic model of the heavy-haul train-track coupled system is established through a modularised method. Specifically, this model includes the subsystems such as the train control, the vehicle, the wheel-rail relation and the line geometries. And for the calculation of the wheel-rail interaction force under the driving or braking conditions, the large creep phenomenon that may occur within the wheel-rail contact patch is considered. For the coupler and draft gear system, the coupler forces in three directions and the coupler lateral tilt angles in curves are calculated. Then, according to the characteristics of the long heavy-haul train, an efficient solving method is developed to improve the computational efficiency for such a large system. Some basic principles which should be followed in order to meet the requirement of calculation accuracy are determined. Finally, the 3-D train-track coupled model is verified by comparing the calculated results with the running test results. It is indicated that the proposed dynamic model could simulate the dynamic performance of the heavy-haul train well.

  16. Adaptive Probabilistic Tracking Embedded in Smart Cameras for Distributed Surveillance in a 3D Model

    Directory of Open Access Journals (Sweden)

    Sven Fleck

    2006-12-01

    Full Text Available Tracking applications based on distributed and embedded sensor networks are emerging today, both in the fields of surveillance and industrial vision. Traditional centralized approaches have several drawbacks, due to limited communication bandwidth, computational requirements, and thus limited spatial camera resolution and frame rate. In this article, we present network-enabled smart cameras for probabilistic tracking. They are capable of tracking objects adaptively in real time and offer a very bandwidthconservative approach, as the whole computation is performed embedded in each smart camera and only the tracking results are transmitted, which are on a higher level of abstraction. Based on this, we present a distributed surveillance system. The smart cameras' tracking results are embedded in an integrated 3D environment as live textures and can be viewed from arbitrary perspectives. Also a georeferenced live visualization embedded in Google Earth is presented.

  17. Modeling and simulation of adaptive multimodal optical sensors for target tracking in the visible to near infrared

    Science.gov (United States)

    Presnar, Michael D.

    This work investigates an integrated aerial remote sensor design approach to address moving target detection and tracking problems within highly cluttered, dynamic ground-based scenes. Sophisticated simulation methodologies and scene phenomenology validations have resulted in advancements in artificial multimodal truth video synthesis. Complex modeling of novel micro-opto-electro-mechanical systems (MOEMS) devices, optical systems, and detector arrays has resulted in a proof of concept for a state-of-the-art imaging spectropolarimeter sensor model that does not suffer from typical multimodal image registration problems. Test methodology developed for this work provides the ability to quantify performance of a target tracking application with varying ground scenery, flight characteristics, or sensor specifications. The culmination of this research is an end-to-end simulated demonstration of multimodal aerial remote sensing and target tracking. Deeply hidden target recognition is shown to be enhanced through the fusing of panchromatic, hyperspectral, and polarimetric image modalities. The Digital Imaging and Remote Sensing Image Generation model was leveraged to synthesize truth spectropolarimetric sensor-reaching radiance image cubes comprised of coregistered Stokes vector bands in the visible to near-infrared. An intricate synthetic urban scene containing numerous moving vehicular targets was imaged from a virtual sensor aboard an aerial platform encircling a stare point. An adaptive sensor model was designed with a superpixel array of MOEMS devices fabricated atop a division of focal plane detector. Degree of linear polarization (DoLP) imagery is acquired by combining three adjacent micropolarizer outputs within each 2x2 superpixel whose respective transmissions vary with wavelength, relative angle of polarization, and wire-grid spacing. A novel micromirror within each superpixel adaptively relays light between a panchromatic imaging channel and a hyperspectral

  18. Imaging infrared: Scene simulation, modeling, and real image tracking; Proceedings of the Meeting, Orlando, FL, Mar. 30, 31, 1989

    Science.gov (United States)

    Triplett, Milton J.; Wolverton, James R.; Hubert, August J.

    1989-09-01

    Various papers on scene simulation, modeling, and real image tracking using IR imaging are presented. Individual topics addressed include: tactical IR scene generator, dynamic FLIR simulation in flight training research, high-speed dynamic scene simulation in UV to IR spectra, development of an IR sensor calibration facility, IR celestial background scene description, transmission measurement of optical components at cryogenic temperatures, diffraction model for a point-source generator, silhouette-based tracking for tactical IR systems, use of knowledge in electrooptical trackers, detection and classification of target formations in IR image sequences, SMPRAD: simplified three-dimensional cloud radiance model, IR target generator, recent advances in testing of thermal imagers, generic IR system models with dynamic image generation, modeling realistic target acquisition using IR sensors in multiple-observer scenarios, and novel concept of scene generation and comprehensive dynamic sensor test.

  19. A Microsoft Project-Based Planning, Tracking, and Management Tool for the National Transonic Facility's Model Changeover Process

    Science.gov (United States)

    Vairo, Daniel M.

    1998-01-01

    The removal and installation of sting-mounted wind tunnel models in the National Transonic Facility (NTF) is a multi-task process having a large impact on the annual throughput of the facility. Approximately ten model removal and installation cycles occur annually at the NTF with each cycle requiring slightly over five days to complete. The various tasks of the model changeover process were modeled in Microsoft Project as a template to provide a planning, tracking, and management tool. The template can also be used as a tool to evaluate improvements to this process. This document describes the development of the template and provides step-by-step instructions on its use and as a planning and tracking tool. A secondary role of this document is to provide an overview of the model changeover process and briefly describe the tasks associated with it.

  20. Particle Tracking Model for Suspended Sediment Transport and Streambed Clogging Under Losing and Gaining Conditions

    Science.gov (United States)

    Preziosi-Ribero, A.; Fox, A.; Packman, A. I.; Escobar-Vargas, J.; Donado-Garzon, L. D.; Li, A.; Arnon, S.

    2017-12-01

    Exchange of mass, momentum and energy between surface water and groundwater is a driving factor for the biology, ecology and chemistry of rivers and water bodies in general. Nonetheless, this exchange is dominated by different factors like topography, bed morphology, and large-scale hydraulic gradient. In the particular case of fine sediments like clay, conservative tracer modeling is impossible because they are trapped in river beds for long periods, thus the normal advection dispersion approach leads to errors and results do not agree with reality. This study proposes a numerical particle tracking model that represents the behavior of kaolinite in a sand flume, and how its deposition varies according to different flow conditions, namely losing and gaining flow. Since fine particles do not behave like solutes, kaolinite dynamics are represented using settling velocity and a filtration coefficient allowing the particles to be trapped in the bed. This approach allows us to use measurable parameters directly related with the fine particle features as size and shape, and hydraulic parameters. Results are then compared with experimental results from lab experiments obtained in a recirculating flume, in order to assess the impact of losing and gaining conditions on sediment transport and deposition. Furthermore, our model is able to identify the zones where kaolinite deposition concentrates over the flume due to the bed geometry, and later relate these results with clogging of the bed and hence changes in the bed's hydraulic conductivity. Our results suggest that kaolinite deposition is higher under losing conditions since the vertical velocity of the flow is added to the deposition velocity of the particles modeled. Moreover, the zones where kaolinite concentrates varies under different flow conditions due to the difference in pressure and velocity in the river bed.

  1. Kinetically Controlled Two-Step Amorphization and Amorphous-Amorphous Transition in Ice

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Chuanlong; Yong, Xue; Tse, John S.; Smith, Jesse S.; Sinogeikin, Stanislav V.; Kenney-Benson, Curtis; Shen, Guoyin

    2017-09-01

    We report the results of in situ structural characterization of the amorphization of crystalline ice Ih under compression and the relaxation of high-density amorphous (HDA) ice under decompression at temperatures between 96 and 160 K by synchrotron x-ray diffraction. The results show that ice Ih transforms to an intermediate crystalline phase at 100 K prior to complete amorphization, which is supported by molecular dynamics calculations. The phase transition pathways show clear temperature dependence: direct amorphization without an intermediate phase is observed at 133 K, while at 145 K a direct Ih-to-IX transformation is observed; decompression of HDA shows a transition to low-density amorphous ice at 96 K and ~ 1 Pa , to ice Ic at 135 K and to ice IX at 145 K. These observations show that the amorphization of compressed ice Ih and the recrystallization of decompressed HDA are strongly dependent on temperature and controlled by kinetic barriers. Pressure-induced amorphous ice is an intermediate state in the phase transition from the connected H-bond water network in low pressure ices to the independent and interpenetrating H-bond network of high-pressure ices.

  2. Modelling of Track Reconstruction Inside Jets with the 2016 ATLAS $\\sqrt{s}= 13$ TeV pp dataset

    CERN Document Server

    The ATLAS collaboration

    2017-01-01

    Inside the core of high transverse momentum jets, the particle density is so high that the tracks of charged particles begin to overlap, and due to the different charged particles, pixel clusters in the ATLAS inner detector begin to merge. This high density environment results in a degradation of track reconstruction. Recent innovations to the ambiguity solving in the charged particle pattern recognition partially mitigate the loss in performance. However, it is critical for all physics results using tracks inside jets that the algorithms be well modeled by simulation. This note presents new measurements of the charged particle reconstruction inefficiency and fake rate inside jets with the $\\sqrt{s}=13$ TeV $pp$ dataset collected by the ATLAS experiment at the LHC in 2016.

  3. Structural morphology of amorphous conducting carbon film

    Indian Academy of Sciences (India)

    Unknown

    been found to be having a lot of technological applica- tions. The properties of these amorphous carbons sensi- tively depend on the relative concentration of sp3 and sp2 hybridized carbons. The resulting amorphous materials are variously referred to as tetrahedral amorphous carbon. (ta-C), amorphous carbon (a-C), ...

  4. Amorphous drugs and dosage forms

    DEFF Research Database (Denmark)

    Grohganz, Holger; Löbmann, K.; Priemel, P.

    2013-01-01

    The transformation to an amorphous form is one of the most promising approaches to address the low solubility of drug compounds, the latter being an increasing challenge in the development of new drug candidates. However, amorphous forms are high energy solids and tend to recry stallize. New...... formulation principles are needed to ensure the stability of amorphous drug forms. The formation of solid dispersions is still the most investigated approach, but additional approaches are desirable to overcome the shortcomings of solid dispersions. Spatial separation by either coating or the use of micro......-containers has shown potential to prevent or delay recrystallization. Another recent approach is the formation of co-amorphous mixtures between either two drugs or one drug and one low molecular weight excipient. Molecular interactions between the two molecules provide an energy barrier that has to be overcome...

  5. A Framework for 3D Model-Based Visual Tracking Using a GPU-Accelerated Particle Filter.

    Science.gov (United States)

    Brown, J A; Capson, D W

    2012-01-01

    A novel framework for acceleration of particle filtering approaches to 3D model-based, markerless visual tracking in monocular video is described. Specifically, we present a methodology for partitioning and mapping the computationally expensive weight-update stage of a particle filter to a graphics processing unit (GPU) to achieve particle- and pixel-level parallelism. Nvidia CUDA and Direct3D are employed to harness the massively parallel computational power of modern GPUs for simulation (3D model rendering) and evaluation (segmentation, feature extraction, and weight calculation) of hundreds of particles at high speeds. The proposed framework addresses the computational intensity that is intrinsic to all particle filter approaches, including those that have been modified to minimize the number of particles required for a particular task. Performance and tracking quality results for rigid object and articulated hand tracking experiments demonstrate markerless, model-based visual tracking on consumer-grade graphics hardware with pixel-level accuracy up to 95 percent at 60+ frames per second. The framework accelerates particle evaluation up to 49 times over a comparable CPU-only implementation, providing an increased particle count while maintaining real-time frame rates.

  6. Transport and Reactive Flow Modelling Using A Particle Tracking Method Based on Continuous Time Random Walks

    Science.gov (United States)

    Oliveira, R.; Bijeljic, B.; Blunt, M. J.; Colbourne, A.; Sederman, A. J.; Mantle, M. D.; Gladden, L. F.

    2017-12-01

    Mixing and reactive processes have a large impact on the viability of enhanced oil and gas recovery projects that involve acid stimulation and CO2 injection. To achieve a successful design of the injection schemes an accurate understanding of the interplay between pore structure, flow and reactive transport is necessary. Dependent on transport and reactive conditions, this complex coupling can also be dependent on initial rock heterogeneity across a variety of scales. To address these issues, we devise a new method to study transport and reactive flow in porous media at multiple scales. The transport model is based on an efficient Particle Tracking Method based on Continuous Time Random Walks (CTRW-PTM) on a lattice. Transport is modelled using an algorithm described in Rhodes and Blunt (2006) and Srinivasan et al. (2010); this model is expanded to enable for reactive flow predictions in subsurface rock undergoing a first-order fluid/solid chemical reaction. The reaction-induced alteration in fluid/solid interface is accommodated in the model through changes in porosity and flow field, leading to time dependent transport characteristics in the form of transit time distributions which account for rock heterogeneity change. This also enables the study of concentration profiles at the scale of interest. Firstly, we validate transport model by comparing the probability of molecular displacement (propagators) measured by Nuclear Magnetic Resonance (NMR) with our modelled predictions for concentration profiles. The experimental propagators for three different porous media of increasing complexity, a beadpack, a Bentheimer sandstone and a Portland carbonate, show a good agreement with the model. Next, we capture the time evolution of the propagators distribution in a reactive flow experiment, where hydrochloric acid is injected into a limestone rock. We analyse the time-evolving non-Fickian signatures for the transport during reactive flow and observe an increase in

  7. Diamond amorphization in neutron irradiation

    International Nuclear Information System (INIS)

    Nikolaenko, V.A.; Gordeev, V.G.

    1996-01-01

    The paper presents the results on neutron irradiation of the diamond in a nuclear reactor. It is shown that the neutron irradiation stimulates the diamond transition to the amorphous state. At a temperature below 750 o K the time required for the diamond-graphite transition decreases with decreasing irradiation temperature. On the contrary, in irradiation at higher temperatures the time of diamond conversion into the amorphous state increases with decreasing but always remains shorter than in the absence of irradiation. (author)

  8. Anomalous magnetoresistance in amorphous metals

    International Nuclear Information System (INIS)

    Kuz'menko, V.M.; Vladychkin, A.N.; Mel'nikov, V.I.; Sudovtsev, A.I.

    1984-01-01

    The magnetoresistance of amorphous Bi, Ca, V and Yb films is investigated in fields up to 4 T at low temperatures. For all metals the magnetoresistance is positive, sharply decreases with growth of temperature and depends anomalously on the magnetic field strength. For amorphous superconductors the results agree satisfactorily with the theory of anomalous magnetoresistance in which allowance is made for scattering of electrons by the superconducting fluctuations

  9. Target model of nucleosome particle for track structure calculations and DNA damage modeling

    Czech Academy of Sciences Publication Activity Database

    Michalik, Věslav; Běgusová, Marie

    1994-01-01

    Roč. 66, č. 3 (1994), s. 267-277 ISSN 0955-3002 R&D Projects: GA ČR(CZ) GA204/93/2451; GA AV ČR(CZ) IA135102; GA AV ČR(CZ) IA50405 Keywords : DNA nucleosome * ionizing radiation * theoretical modeling Subject RIV: AQ - Safety, Health Protection, Human - Machine Impact factor: 2.761, year: 1994

  10. Glue detection based on teaching points constraint and tracking model of pixel convolution

    Science.gov (United States)

    Geng, Lei; Ma, Xiao; Xiao, Zhitao; Wang, Wen

    2018-01-01

    On-line glue detection based on machine version is significant for rust protection and strengthening in car production. Shadow stripes caused by reflect light and unevenness of inside front cover of car reduce the accuracy of glue detection. In this paper, we propose an effective algorithm to distinguish the edges of the glue and shadow stripes. Teaching points are utilized to calculate slope between the two adjacent points. Then a tracking model based on pixel convolution along motion direction is designed to segment several local rectangular regions using distance. The distance is the height of rectangular region. The pixel convolution along the motion direction is proposed to extract edges of gules in local rectangular region. A dataset with different illumination and complexity shape stripes are used to evaluate proposed method, which include 500 thousand images captured from the camera of glue gun machine. Experimental results demonstrate that the proposed method can detect the edges of glue accurately. The shadow stripes are distinguished and removed effectively. Our method achieves the 99.9% accuracies for the image dataset.

  11. Recognition of risk situations based on endoscopic instrument tracking and knowledge based situation modeling

    Science.gov (United States)

    Speidel, Stefanie; Sudra, Gunther; Senemaud, Julien; Drentschew, Maximilian; Müller-Stich, Beat Peter; Gutt, Carsten; Dillmann, Rüdiger

    2008-03-01

    Minimally invasive surgery has gained significantly in importance over the last decade due to the numerous advantages on patient-side. The surgeon has to adapt special operation-techniques and deal with difficulties like the complex hand-eye coordination, limited field of view and restricted mobility. To alleviate these constraints we propose to enhance the surgeon's capabilities by providing a context-aware assistance using augmented reality (AR) techniques. In order to generate a context-aware assistance it is necessary to recognize the current state of the intervention using intraoperatively gained sensor data and a model of the surgical intervention. In this paper we present the recognition of risk situations, the system warns the surgeon if an instrument gets too close to a risk structure. The context-aware assistance system starts with an image-based analysis to retrieve information from the endoscopic images. This information is classified and a semantic description is generated. The description is used to recognize the current state and launch an appropriate AR visualization. In detail we present an automatic vision-based instrument tracking to obtain the positions of the instruments. Situation recognition is performed using a knowledge representation based on a description logic system. Two augmented reality visualization programs are realized to warn the surgeon if a risk situation occurs.

  12. Disturbance observer-based L1 robust tracking control for hypersonic vehicles with T-S disturbance modeling

    Directory of Open Access Journals (Sweden)

    Yang Yi

    2016-11-01

    Full Text Available This article concerns a disturbance observer-based L1 robust anti-disturbance tracking algorithm for the longitudinal models of hypersonic flight vehicles with different kinds of unknown disturbances. On one hand, by applying T-S fuzzy models to represent those modeled disturbances, a disturbance observer relying on T-S disturbance models can be constructed to track the dynamics of exogenous disturbances. On the other hand, L1 index is introduced to analyze the attenuation performance of disturbance for those unmodeled disturbances. By utilizing the existing convex optimization algorithm, a disturbance observer-based proportional-integral-controlled input is proposed such that the stability of hypersonic flight vehicles can be ensured and the tracking error for velocity and altitude in hypersonic flight vehicle models can converge to equilibrium point. Furthermore, the satisfactory disturbance rejection and attenuation with L1 index can be obtained simultaneously. Simulation results on hypersonic flight vehicle models can reflect the feasibility and effectiveness of the proposed control algorithm.

  13. A non-reflecting boundary for use in a finite element beam model of a railway track

    Science.gov (United States)

    Yang, Jiannan; Thompson, David J.

    2015-02-01

    Some beam-like structures such as a railway track are effectively infinite in nature. Analytical solutions exist for simple structures but numerical methods like the finite element (FE) method are often employed to study more complicated problems. However, when the FE method is used for structures of infinite extent it is essential to introduce artificial boundaries to limit the area of computation. Here, a non-reflecting boundary is developed using a damped tapered tip for application in a finite element model representing an infinite supported beam. The FE model of the tapered tip is validated against an analytical model based on Bessel functions. The reflection characteristics of the FE tapered tip are quantified using a wave/FE superposition method. It is shown that the damped tapered tip is much more effective than its constant counterpart and achieves reduction of the model size. The damped tapered tip is applied to a simple FE railway track model and good agreement is found when its point mobility is compared with an analytical infinite track model.

  14. Hydrogenated amorphous silicon photonics

    Science.gov (United States)

    Narayanan, Karthik

    2011-12-01

    Silicon Photonics is quickly proving to be a suitable interconnect technology for meeting the future goals of on-chip bandwidth and low power requirements. However, it is not clear how silicon photonics will be integrated into CMOS chips, particularly microprocessors. The issue of integrating photonic circuits into electronic IC fabrication processes to achieve maximum flexibility and minimum complexity and cost is an important one. In order to minimize usage of chip real estate, it will be advantageous to integrate in three-dimensions. Hydrogenated amorphous silicon (a-Si:H) is emerging as a promising material for the 3-D integration of silicon photonics for on-chip optical interconnects. In addition, a-Si:H film can be deposited using CMOS compatible low temperature plasma-enhanced chemical vapor deposition (PECVD) process at any point in the fabrication process allowing maximum flexibility and minimal complexity. In this thesis, we demonstrate a-Si:H as a high performance alternate platform to crystalline silicon, enabling backend integration of optical interconnects in a hybrid photonic-electronic network-on-chip architecture. High quality passive devices are fabricated on a low-loss a-Si:H platform enabling wavelength division multiplexing schemes. We demonstrate a broadband all-optical modulation scheme based on free-carrier absorption effect, which can enable compact electro-optic modulators in a-Si:H. Furthermore, we comprehensively characterize the optical nonlinearities in a-Si:H and observe that a-Si:H exhibits enhanced nonlinearities as compared to crystalline silicon. Based on the enhanced nonlinearities, we demonstrate low-power four-wave mixing in a-Si:H waveguides enabling high speed all-optical devices in an a-Si:H platform. Finally, we demonstrate a novel data encoding scheme using thermal and all-optical tuning of silicon waveguides, increasing the spectral efficiency in an interconnect link.

  15. Kinematic Model-Based Pedestrian Dead Reckoning for Heading Correction and Lower Body Motion Tracking

    Directory of Open Access Journals (Sweden)

    Min Su Lee

    2015-11-01

    Full Text Available In this paper, we present a method for finding the enhanced heading and position of pedestrians by fusing the Zero velocity UPdaTe (ZUPT-based pedestrian dead reckoning (PDR and the kinematic constraints of the lower human body. ZUPT is a well known algorithm for PDR, and provides a sufficiently accurate position solution for short term periods, but it cannot guarantee a stable and reliable heading because it suffers from magnetic disturbance in determining heading angles, which degrades the overall position accuracy as time passes. The basic idea of the proposed algorithm is integrating the left and right foot positions obtained by ZUPTs with the heading and position information from an IMU mounted on the waist. To integrate this information, a kinematic model of the lower human body, which is calculated by using orientation sensors mounted on both thighs and calves, is adopted. We note that the position of the left and right feet cannot be apart because of the kinematic constraints of the body, so the kinematic model generates new measurements for the waist position. The Extended Kalman Filter (EKF on the waist data that estimates and corrects error states uses these measurements and magnetic heading measurements, which enhances the heading accuracy. The updated position information is fed into the foot mounted sensors, and reupdate processes are performed to correct the position error of each foot. The proposed update-reupdate technique consequently ensures improved observability of error states and position accuracy. Moreover, the proposed method provides all the information about the lower human body, so that it can be applied more effectively to motion tracking. The effectiveness of the proposed algorithm is verified via experimental results, which show that a 1.25% Return Position Error (RPE with respect to walking distance is achieved.

  16. Kinematic Model-Based Pedestrian Dead Reckoning for Heading Correction and Lower Body Motion Tracking.

    Science.gov (United States)

    Lee, Min Su; Ju, Hojin; Song, Jin Woo; Park, Chan Gook

    2015-11-06

    In this paper, we present a method for finding the enhanced heading and position of pedestrians by fusing the Zero velocity UPdaTe (ZUPT)-based pedestrian dead reckoning (PDR) and the kinematic constraints of the lower human body. ZUPT is a well known algorithm for PDR, and provides a sufficiently accurate position solution for short term periods, but it cannot guarantee a stable and reliable heading because it suffers from magnetic disturbance in determining heading angles, which degrades the overall position accuracy as time passes. The basic idea of the proposed algorithm is integrating the left and right foot positions obtained by ZUPTs with the heading and position information from an IMU mounted on the waist. To integrate this information, a kinematic model of the lower human body, which is calculated by using orientation sensors mounted on both thighs and calves, is adopted. We note that the position of the left and right feet cannot be apart because of the kinematic constraints of the body, so the kinematic model generates new measurements for the waist position. The Extended Kalman Filter (EKF) on the waist data that estimates and corrects error states uses these measurements and magnetic heading measurements, which enhances the heading accuracy. The updated position information is fed into the foot mounted sensors, and reupdate processes are performed to correct the position error of each foot. The proposed update-reupdate technique consequently ensures improved observability of error states and position accuracy. Moreover, the proposed method provides all the information about the lower human body, so that it can be applied more effectively to motion tracking. The effectiveness of the proposed algorithm is verified via experimental results, which show that a 1.25% Return Position Error (RPE) with respect to walking distance is achieved.

  17. Theoretical model and experimental verification on the PID tracking method using liquid crystal optical phased array

    Science.gov (United States)

    Wang, Xiangru; Xu, Jianhua; Huang, Ziqiang; Wu, Liang; Zhang, Tianyi; Wu, Shuanghong; Qiu, Qi

    2017-02-01

    Liquid crystal optical phased array (LC-OPA) has been considered with great potential on the non-mechanical laser deflector because it is fabricated using photolithographic patterning technology which has been well advanced by the electronics and display industry. As a vital application of LC-OPA, free space laser communication has demonstrated its merits on communication bandwidth. Before data communication, ATP (acquisition, tracking and pointing) process costs relatively long time to result in a bottle-neck of free space laser communication. Meanwhile, dynamic real time accurate tracking is sensitive to keep a stable communication link. The electro-optic medium liquid crystal with low driving voltage can be used as the laser beam deflector. This paper presents a fast-track method using liquid crystal optical phased array as the beam deflector, CCD as a beacon light detector. PID (Proportion Integration Differentiation) loop algorithm is introduced as the controlling algorithm to generate the corresponding steering angle. To achieve the goal of fast and accurate tracking, theoretical analysis and experimental verification are demonstrated that PID closed-loop system can suppress the attitude random vibration. Meanwhile, theoretical analysis shows that tracking accuracy can be less than 6.5μrad, with a relative agreement with experimental results which is obtained after 10 adjustments that the tracking accuracy is less than12.6μrad.

  18. Cradle-to-Grave Tracking and process and modeling using GIS techniques

    Energy Technology Data Exchange (ETDEWEB)

    Kjeldgaard, E.A. [Sandia National Labs., Albuquerque, NM (United States); Horak, K.; Hollingsworth, M. [Ogden Environmental and Energy Services, Albuquerque, NM (United States)

    1994-04-01

    A Cradle-to-Grave Tracking and Information System (CGTIS) is being developed as an integral part of the Sandia National Laboratories` pollution prevention program. The system will interface with safety, health, and risk management systems. The CGTIS is designed in a modular fashion to take advantage of systems currently in place at SNL, and to enhance transfer of the technology to other facilities. The system will be composed initially of three major database modules (chemical tracking, process information, and waste tracking). The chemical waste tracking module is operational now; the process information module is currently under development (in conjunction with our pollution prevention opportunity assessment program) and should be operational in 1994. Tracking of radioactive waste will be linked to the chemical waste tracking system to provide an integrated chemical/rad waste module. Geographic information system technology, commercially available for personal computers, is being added to the CGTIS to enhance its capabilities and to bring a new level of access to and analysis of the data residing in the CGTIS.

  19. Tracking Control of a Magnetic Shape Memory Actuator Using an Inverse Preisach Model with Modified Fuzzy Sliding Mode Control

    Directory of Open Access Journals (Sweden)

    Jhih-Hong Lin

    2016-08-01

    Full Text Available Magnetic shape memory (MSM alloys are a new class of smart materials with extraordinary strains up to 12% and frequencies in the range of 1 to 2 kHz. The MSM actuator is a potential device which can achieve high performance electromagnetic actuation by using the properties of MSM alloys. However, significant non-linear hysteresis behavior is a significant barrier to control the MSM actuator. In this paper, the Preisach model was used, by capturing experiments from different input signals and output responses, to model the hysteresis of MSM actuator, and the inverse Preisach model, as a feedforward control, provided compensational signals to the MSM actuator to linearize the hysteresis non-linearity. The control strategy for path tracking combined the hysteresis compensator and the modified fuzzy sliding mode control (MFSMC which served as a path controller. Based on the experimental results, it was verified that a tracking error in the order of micrometers was achieved.

  20. Conception and modelling of photo-detection pixels. PIN photodiodes conceived in amorphous silicon for particles detection; Conception et modelisation de pixels de photodetection: Photodiodes PIN en silicium amorphe en vue de leurs utilisations comme detecteurs de particules

    Energy Technology Data Exchange (ETDEWEB)

    Negru, R

    2008-06-15

    The research done has revealed that the a-Si:H is a material ideally suited for the detection of particles, while being resistant to radiation. It also has a low manufacturing cost, is compatible with existing technology and can be deposited over large areas. Thus, despite the low local mobility of charges (30 cm{sup 2}/V/s), a-Si:H is a material of particular interest for manufacturing high-energy particle detection pixels. As a consequence of this, we have studied the feasibility of an experimental pixel stacked structure based on a-Si:H as a basic sensor element for an electromagnetic calorimeter. The structure of such a pixel consists of different components. First, a silicon PIN diode in a-Si:H is fabricated, followed by a bias resistor and a decoupling capacitor. Before such a structure is made and in order to optimize its design, it is essential to have an efficient behavioural model of the various components. Thus, our primary goal was to develop a two-dimensional physical model of the PIN diode using the SILVACO finite element calculation software. This a-Si:H PIN diode two-dimensional physical model allowed us to study the problem of crosstalk between pixels in a matrix structure of detectors. In particular, we concentrated on the leakage current and the current generated in the volume between neighbouring pixels. The successful implementation of this model in SPICE ensures its usefulness in other professional simulators and especially its integration into a complete electronic structure (PIN diode, bias resistor, decoupling capacity and low noise amplifier). Thanks to these modelling tools, we were able to simulate PIN diode structures in a-Si:H with different thicknesses and different dimensions. These simulations have allowed us to predict that the thicker structures are relevant to the design of the pixel detectors for high energy physics. Applications in astronomy, medical imaging and the analysis of the failure of silicon integrated circuits, can

  1. Intrinsic electron trapping in amorphous oxide

    Science.gov (United States)

    Strand, Jack; Kaviani, Moloud; Afanas’ev, Valeri V.; Lisoni, Judit G.; Shluger, Alexander L.

    2018-03-01

    We demonstrate that electron trapping at intrinsic precursor sites is endemic in non-glass-forming amorphous oxide films. The energy distributions of trapped electron states in ultra-pure prototype amorphous (a)-HfO2 insulator obtained from exhaustive photo-depopulation experiments demonstrate electron states in the energy range of 2–3 eV below the oxide conduction band. These energy distributions are compared to the results of density functional calculations of a-HfO2 models of realistic density. The experimental results can be explained by the presence of intrinsic charge trapping sites formed by under-coordinated Hf cations and elongated Hf–O bonds in a-HfO2. These charge trapping states can capture up to two electrons, forming polarons and bi-polarons. The corresponding trapping sites are different from the dangling-bond type defects responsible for trapping in glass-forming oxides, such as SiO2, in that the traps are formed without bonds being broken. Furthermore, introduction of hydrogen causes formation of somewhat energetically deeper electron traps when a proton is immobilized next to the trapped electron bi-polaron. The proposed novel mechanism of intrinsic charge trapping in a-HfO2 represents a new paradigm for charge trapping in a broad class of non-glass-forming amorphous insulators.

  2. Southern Hemisphere Application of the Systematic Approach to Tropical Cyclone Forecasting Part IV: Sources of Large Track Errors by Dynamical Models

    National Research Council Canada - National Science Library

    Reader, Grahame

    2000-01-01

    Sources of 72-h track errors> 300 n mi by four dynamical model tropical cyclone predictions in the Southern Hemisphere during the 1997-98 and 1998-99 seasons are studied using conceptual models Carr and Elsberry have previously...

  3. Southern Hemisphere Application of the Systematic Approach to Tropical Cyclone Forecasting Part 4: Sources of Large Track Errors by Dynamical Models

    National Research Council Canada - National Science Library

    Reader, Grahame

    2000-01-01

    Sources of 72-h track errors > 300 n mi by four dynamical model tropical cyclone predictions in the Southern Hemisphere during the 1997-98 and 1998-99 seasons are studied using conceptual models Carr and Elsberry have previously...

  4. Prediction of Phase Behavior of Spray-Dried Amorphous Solid Dispersions: Assessment of Thermodynamic Models, Standard Screening Methods and a Novel Atomization Screening Device with Regard to Prediction Accuracy

    Directory of Open Access Journals (Sweden)

    Aymeric Ousset

    2018-03-01

    Full Text Available The evaluation of drug–polymer miscibility in the early phase of drug development is essential to ensure successful amorphous solid dispersion (ASD manufacturing. This work investigates the comparison of thermodynamic models, conventional experimental screening methods (solvent casting, quench cooling, and a novel atomization screening device based on their ability to predict drug–polymer miscibility, solid state properties (Tg value and width, and adequate polymer selection during the development of spray-dried amorphous solid dispersions (SDASDs. Binary ASDs of four drugs and seven polymers were produced at 20:80, 40:60, 60:40, and 80:20 (w/w. Samples were systematically analyzed using modulated differential scanning calorimetry (mDSC and X-ray powder diffraction (XRPD. Principal component analysis (PCA was used to qualitatively assess the predictability of screening methods with regards to SDASD development. Poor correlation was found between theoretical models and experimentally-obtained results. Additionally, the limited ability of usual screening methods to predict the miscibility of SDASDs did not guarantee the appropriate selection of lead excipient for the manufacturing of robust SDASDs. Contrary to standard approaches, our novel screening device allowed the selection of optimal polymer and drug loading and established insight into the final properties and performance of SDASDs at an early stage, therefore enabling the optimization of the scaled-up late-stage development.

  5. Prediction of Phase Behavior of Spray-Dried Amorphous Solid Dispersions: Assessment of Thermodynamic Models, Standard Screening Methods and a Novel Atomization Screening Device with Regard to Prediction Accuracy.

    Science.gov (United States)

    Ousset, Aymeric; Chavez, Pierre-François; Meeus, Joke; Robin, Florent; Schubert, Martin Alexander; Somville, Pascal; Dodou, Kalliopi

    2018-03-07

    The evaluation of drug-polymer miscibility in the early phase of drug development is essential to ensure successful amorphous solid dispersion (ASD) manufacturing. This work investigates the comparison of thermodynamic models, conventional experimental screening methods (solvent casting, quench cooling), and a novel atomization screening device based on their ability to predict drug-polymer miscibility, solid state properties ( T g value and width), and adequate polymer selection during the development of spray-dried amorphous solid dispersions (SDASDs). Binary ASDs of four drugs and seven polymers were produced at 20:80, 40:60, 60:40, and 80:20 ( w / w ). Samples were systematically analyzed using modulated differential scanning calorimetry (mDSC) and X-ray powder diffraction (XRPD). Principal component analysis (PCA) was used to qualitatively assess the predictability of screening methods with regards to SDASD development. Poor correlation was found between theoretical models and experimentally-obtained results. Additionally, the limited ability of usual screening methods to predict the miscibility of SDASDs did not guarantee the appropriate selection of lead excipient for the manufacturing of robust SDASDs. Contrary to standard approaches, our novel screening device allowed the selection of optimal polymer and drug loading and established insight into the final properties and performance of SDASDs at an early stage, therefore enabling the optimization of the scaled-up late-stage development.

  6. Structure and Properties of Amorphous Transparent Conducting Oxides

    Science.gov (United States)

    Medvedeva, Julia

    Driven by technological appeal, the research area of amorphous oxide semiconductors has grown tremendously since the first demonstration of the unique properties of amorphous indium oxide more than a decade ago. Today, amorphous oxides, such as a-ITO, a-IZO, a-IGZO, or a-ZITO, exhibit the optical, electrical, thermal, and mechanical properties that are comparable or even superior to those possessed by their crystalline counterparts, pushing the latter out of the market. Large-area uniformity, low-cost low-temperature deposition, high carrier mobility, optical transparency, and mechanical flexibility make these materials appealing for next-generation thin-film electronics. Yet, the structural variations associated with crystalline-to-amorphous transition as well as their role in carrier generation and transport properties of these oxides are far from being understood. Although amorphous oxides lack grain boundaries, factors like (i) size and distribution of nanocrystalline inclusions; (ii) spatial distribution and clustering of incorporated cations in multicomponent oxides; (iii) formation of trap defects; and (iv) piezoelectric effects associated with internal strains, will contribute to electron scattering. In this work, ab-initio molecular dynamics (MD) and accurate density-functional approaches are employed to understand how the properties of amorphous ternary and quaternary oxides depend on quench rates, cation compositions, and oxygen stoichiometries. The MD results, combined with thorough experimental characterization, reveal that interplay between the local and long-range structural preferences of the constituent oxides gives rise to a complex composition-dependent structural behavior in the amorphous oxides. The proposed network models of metal-oxygen polyhedra help explain the observed intriguing electrical and optical properties in In-based oxides and suggest ways to broaden the phase space of amorphous oxide semiconductors with tunable properties. The

  7. Altered defaecatory behaviour and faecal incontinence in a video-tracked animal model of pudendal neuropathy.

    Science.gov (United States)

    Devane, L A; Lucking, E; Evers, J; Buffini, M; Scott, S M; Knowles, C H; O'Connell, P R; Jones, J F X

    2017-05-01

    The aim was to develop a behavioural animal model of faecal continence and assess the effect of retro-uterine balloon inflation (RBI) injury. RBI in the rat causes pudendal neuropathy, a risk factor for obstetric related faecal incontinence in humans. Video-tracking of healthy rats (n = 12) in a cage containing a latrine box was used to monitor their defaecatory behaviour index (DBI) over 2 weeks. The DBI (range 0-1) was devised by dividing the defaecation rate (pellets per hour) outside the latrine by that of the whole cage. A score of 0 indicates all pellets were deposited in the latrine. Subsequently, the effects of RBI (n = 19), sham surgery (n = 4) and colostomy (n = 2) were determined by monitoring the DBI for 2 weeks preoperatively and 3 weeks postoperatively. The DBI for healthy rats was 0.1 ± 0.03 with no significant change over 2 weeks (P = 0.71). In the RBI group, 13 of 19 rats (68%) showed no significant change in DBI postoperatively (0.08 ±  -0.05 vs 0.11 ±  -0.07) while in six rats the DBI increased from 0.16 ±  -0.09 to 0.46 ± 0.23. The negative control, sham surgery, did not significantly affect the DBI (0.09 ± 0.06 vs 0.08 ± 0.04, P = 0.14). The positive control, colostomy, increased the DBI from 0.26 ± 0.03 to 0.86 ± 0.08. This is the first study showing a quantifiable change in defaecatory behaviour following injury in an animal model. This model of pudendal neuropathy affects continence in 32% of rats and provides a basis for research on interventions for incontinence. Colorectal Disease © 2017 The Association of Coloproctology of Great Britain and Ireland.

  8. Investigating added value of regional climate modeling in North American winter storm track simulations

    Science.gov (United States)

    Poan, E. D.; Gachon, P.; Laprise, R.; Aider, R.; Dueymes, G.

    2018-03-01

    Extratropical Cyclone (EC) characteristics depend on a combination of large-scale factors and regional processes. However, the latter are considered to be poorly represented in global climate models (GCMs), partly because their resolution is too coarse. This paper describes a framework using possibilities given by regional climate models (RCMs) to gain insight into storm activity during winter over North America (NA). Recent past climate period (1981-2005) is considered to assess EC activity over NA using the NCEP regional reanalysis (NARR) as a reference, along with the European reanalysis ERA-Interim (ERAI) and two CMIP5 GCMs used to drive the Canadian Regional Climate Model—version 5 (CRCM5) and the corresponding regional-scale simulations. While ERAI and GCM simulations show basic agreement with NARR in terms of climatological storm track patterns, detailed bias analyses show that, on the one hand, ERAI presents statistically significant positive biases in terms of EC genesis and therefore occurrence while capturing their intensity fairly well. On the other hand, GCMs present large negative intensity biases in the overall NA domain and particularly over NA eastern coast. In addition, storm occurrence over the northwestern topographic regions is highly overestimated. When the CRCM5 is driven by ERAI, no significant skill deterioration arises and, more importantly, all storm characteristics near areas with marked relief and over regions with large water masses are significantly improved with respect to ERAI. Conversely, in GCM-driven simulations, the added value contributed by CRCM5 is less prominent and systematic, except over western NA areas with high topography and over the Western Atlantic coastlines where the most frequent and intense ECs are located. Despite this significant added-value on seasonal-mean characteristics, a caveat is raised on the RCM ability to handle storm temporal `seriality', as a measure of their temporal variability at a given

  9. From tracking code to analysis generalised Courant-Snyder theory for any accelerator model

    CERN Document Server

    Forest, Etienne

    2016-01-01

    This book illustrates a theory well suited to tracking codes, which the author has developed over the years. Tracking codes now play a central role in the design and operation of particle accelerators. The theory is fully explained step by step with equations and actual codes that the reader can compile and run with freely available compilers. In this book, the author pursues a detailed approach based on finite “s”-maps, since this is more natural as long as tracking codes remain at the center of accelerator design. The hierarchical nature of software imposes a hierarchy that puts map-based perturbation theory above any other methods. This is not a personal choice: it follows logically from tracking codes overloaded with a truncated power series algebra package. After defining abstractly and briefly what a tracking code is, the author illustrates most of the accelerator perturbation theory using an actual code: PTC. This book may seem like a manual for PTC; however, the reader is encouraged to explore...

  10. Hybrid neuromusculoskeletal modeling to best track joint moments using a balance between muscle excitations derived from electromyograms and optimization.

    Science.gov (United States)

    Sartori, Massimo; Farina, Dario; Lloyd, David G

    2014-11-28

    Current electromyography (EMG)-driven musculoskeletal models are used to estimate joint moments measured from an individual׳s extremities during dynamic movement with varying levels of accuracy. The main benefit is the underlying musculoskeletal dynamics is simulated as a function of realistic, subject-specific, neural-excitation patterns provided by the EMG data. The main disadvantage is surface EMG cannot provide information on deeply located muscles. Furthermore, EMG data may be affected by cross-talk, recording and post-processing artifacts that could adversely influence the EMG׳s information content. This limits the EMG-driven model׳s ability to calculate the multi-muscle dynamics and the resulting joint moments about multiple degrees of freedom. We present a hybrid neuromusculoskeletal model that combines calibration, subject-specificity, EMG-driven and static optimization methods together. In this, the joint moment tracking errors are minimized by balancing the information content extracted from the experimental EMG data and from that generated by a static optimization method. Using movement data from five healthy male subjects during walking and running we explored the hybrid model׳s best configuration to minimally adjust recorded EMGs and predict missing EMGs while attaining the best tracking of joint moments. Minimally adjusted and predicted excitations substantially improved the experimental joint moment tracking accuracy than current EMG-driven models. The ability of the hybrid model to predict missing muscle EMGs was also examined. The proposed hybrid model enables muscle-driven simulations of human movement while enforcing physiological constraints on muscle excitation patterns. This might have important implications for studying pathological movement for which EMG recordings are limited.

  11. Photometrically-derived properties of massive-star clusters obtained with different massive-star evolution tracks and deterministic models

    Science.gov (United States)

    Wofford, Aida; Charlot, Stéphane; Eldridge, John

    2015-08-01

    We compute libraries of stellar + nebular spectra of populations of coeval stars with ages of Auckland tracks for single non-rotating and binary stars. For the stellar component, we use population synthesis codes galaxev, starburst99, and BPASS, depending on the set of tracks. For the nebular component we use photoionization code cloudy. From these spectra, we obtain magnitudes in filters F275W, F336W, F438W, F547M, F555W, F657N, and F814W of the Hubble Space Telescope (HST) Wide Field Camera Three. We use i) our computed magnitudes, ii) new multi-band photometry of massive-star clusters in nearby (<11 Mpc) galaxies spanning the metallicity range 12+log(O/H)=7.2-9.2, observed as part of HST programs 13364 (PI Calzetti) and 13773 (PI Chandar), and iii) Bayesian inference to a) establish how well the different models are able to constrain the metallicities, extinctions, ages, and masses of the star clusters, b) quantify differences in the cluster properties obtained with the different models, and c) assess how properties of lower-mass clusters are affected by the stochastic sampling of the IMF. In our models, the stellar evolution tracks, stellar atmospheres, and nebulae have similar chemical compositions. Different metallicities are available with different sets of tracks and we compare results from models of similar metallicities. Our results have implications for studies of the formation and evolution of star clusters, the cluster age and mass functions, and the star formation histories of galaxies.

  12. Study of a tracking and data acquisition system for the 1990's. Volume 3: TDAS Communication Mission Model

    Science.gov (United States)

    Mccreary, T.

    1983-01-01

    A parametric description of the communication channels required between the user spacecraft to be supported and the user ground data systems is developed. Scenarios of mission models, which reflect a range of free flyers vs space platform usage as well as levels of NASA activity and potential support for military missions, and potential channel requirements which identify: (1) bounds on TDAS forward and return link data communication demand, and (2) the additional demand for providing navigation/tracking support are covered.

  13. Two-stage unified stretched-exponential model for time-dependence of threshold voltage shift under positive-bias-stresses in amorphous indium-gallium-zinc oxide thin-film transistors

    Science.gov (United States)

    Jeong, Chan-Yong; Kim, Hee-Joong; Hong, Sae-Young; Song, Sang-Hun; Kwon, Hyuck-In

    2017-08-01

    In this study, we show that the two-stage unified stretched-exponential model can more exactly describe the time-dependence of threshold voltage shift (ΔV TH) under long-term positive-bias-stresses compared to the traditional stretched-exponential model in amorphous indium-gallium-zinc oxide (a-IGZO) thin-film transistors (TFTs). ΔV TH is mainly dominated by electron trapping at short stress times, and the contribution of trap state generation becomes significant with an increase in the stress time. The two-stage unified stretched-exponential model can provide useful information not only for evaluating the long-term electrical stability and lifetime of the a-IGZO TFT but also for understanding the stress-induced degradation mechanism in a-IGZO TFTs.

  14. Nanostructures having crystalline and amorphous phases

    Science.gov (United States)

    Mao, Samuel S; Chen, Xiaobo

    2015-04-28

    The present invention includes a nanostructure, a method of making thereof, and a method of photocatalysis. In one embodiment, the nanostructure includes a crystalline phase and an amorphous phase in contact with the crystalline phase. Each of the crystalline and amorphous phases has at least one dimension on a nanometer scale. In another embodiment, the nanostructure includes a nanoparticle comprising a crystalline phase and an amorphous phase. The amorphous phase is in a selected amount. In another embodiment, the nanostructure includes crystalline titanium dioxide and amorphous titanium dioxide in contact with the crystalline titanium dioxide. Each of the crystalline and amorphous titanium dioxide has at least one dimension on a nanometer scale.

  15. Hidden Markov model tracking of continuous gravitational waves from a binary neutron star with wandering spin. II. Binary orbital phase tracking

    Science.gov (United States)

    Suvorova, S.; Clearwater, P.; Melatos, A.; Sun, L.; Moran, W.; Evans, R. J.

    2017-11-01

    A hidden Markov model (HMM) scheme for tracking continuous-wave gravitational radiation from neutron stars in low-mass x-ray binaries (LMXBs) with wandering spin is extended by introducing a frequency-domain matched filter, called the J -statistic, which sums the signal power in orbital sidebands coherently. The J -statistic is similar but not identical to the binary-modulated F -statistic computed by demodulation or resampling. By injecting synthetic LMXB signals into Gaussian noise characteristic of the Advanced Laser Interferometer Gravitational-wave Observatory (Advanced LIGO), it is shown that the J -statistic HMM tracker detects signals with characteristic wave strain h0≥2 ×10-26 in 370 d of data from two interferometers, divided into 37 coherent blocks of equal length. When applied to data from Stage I of the Scorpius X-1 Mock Data Challenge organized by the LIGO Scientific Collaboration, the tracker detects all 50 closed injections (h0≥6.84 ×10-26), recovering the frequency with a root-mean-square accuracy of ≤1.95 ×10-5 Hz . Of the 50 injections, 43 (with h0≥1.09 ×10-25) are detected in a single, coherent 10 d block of data. The tracker employs an efficient, recursive HMM solver based on the Viterbi algorithm, which requires ˜105 CPU-hours for a typical broadband (0.5 kHz) LMXB search.

  16. Kinetics of amorphous silica dissolution and the paradox of the silica polymorphs

    OpenAIRE

    Dove, Patricia M.; Han, Nizhou; Wallace, Adam F.; De Yoreo, James J.

    2008-01-01

    The mechanisms by which amorphous silica dissolves have proven elusive because noncrystalline materials lack the structural order that allows them to be studied by the classical terrace, ledge, kink-based models applied to crystals. This would seem to imply amorphous phases have surfaces that are disordered at an atomic scale so that the transfer of SiO4 tetrahedra to solution always leaves the surface free energy of the solid unchanged. As a consequence, dissolution rates of amorphous phases...

  17. Improvements to the ShipIR/NTCS adaptive track gate algorithm and 3D flare particle model

    Science.gov (United States)

    Ramaswamy, Srinivasan; Vaitekunas, David A.; Gunter, Willem H.; February, Faith J.

    2017-05-01

    A key component in any image-based tracking system is the adaptive tracking algorithm used to segment the image into potential targets, rank-and-select the best candidate target, and gate the selected target to further improve tracker performance. Similarly, a key component in any soft-kill response to an incoming guided missile is the flare/chaff decoy used to distract or seduce the seeker homing system away from the naval platform. This paper describes the recent improvements to the naval threat countermeasure simulator (NTCS) of the NATO-standard ship signature model (ShipIR). Efforts to analyse and match the 3D flare particle model against actual IR measurements of the Chemring TALOS IR round resulted in further refinement of the 3D flare particle distribution. The changes in the flare model characteristics were significant enough to require an overhaul to the adaptive track gate (ATG) algorithm in the way it detects the presence of flare decoys and reacquires the target after flare separation. A series of test scenarios are used to demonstrate the impact of the new flare and ATG on IR tactics simulation.

  18. Analysing Possible Applications for Available Mathematical Models of Tracked Vehicle Movement Over the Rough Terrain to Examine Tracked Chain Dynamic Processes

    OpenAIRE

    M. E. Lupyan; K. S. Kuzminov

    2014-01-01

    The article offered for consideration provides a survey of methods to study a tracked vehicle movement over unpaved grounds and obstacles using various software systems. The relevant issue is to optimize chassis elements of a caterpillar at the design stage. The challenges, engineers face using different methods to study the tracked vehicle elements, are given. Advantages of using simulation to study a state of the various components of the loaded chassis are described. Beside, an important a...

  19. Using active contour models for feature extraction in camera-based seam tracking of arc welding

    DEFF Research Database (Denmark)

    Liu, Jinchao; Fan, Zhun; Olsen, Søren

    2009-01-01

    . It is highly desirable to extract groove features closer to the arc and thus facilitate for a nearly-closed-loop control situation. On the other hand, for performing seam tracking and nearly-closed-loop control it is not necessary to obtain very detailed information about the molten pool area as long as some...

  20. Tracking the reading eye: towards a model of real-world reading

    NARCIS (Netherlands)

    Jarodzka, Halszka; Brand-Gruwel, Saskia

    2018-01-01

    Eye tracking has helped to understand the process of reading a word or a sentence, and this research has been very fruitful over the past decades. However, everyday real-world reading dramatically differs from this scenario: we read a newspaper on the bus, surf the Internet for movie reviews or

  1. Modelling Spatial Patterns of Outdoor Physical Activities using Mobile Sports Tracking Application Data

    NARCIS (Netherlands)

    Sileryte, R.; Nourian Ghadikolaee, P.; Van der Spek, S.C.

    2016-01-01

    The paper presents a workflow for collecting, structuring and processing geo-referenced recreational mobility data from a sports tracking application as to monitor recreational usage of urban spaces. The data collected include GPS trajectories of people walking, jogging, and running for recreational

  2. Dynamic Modeling and Simulation of Marine Satellite Tracking Antenna Using Lagrange Method

    DEFF Research Database (Denmark)

    Wang, Yunlong; Soltani, Mohsen; Hussain, Dil muhammed Akbar

    2016-01-01

    Marine Satellite Tracking Antenna (MSTA) is a necessary device in ships for receiving satellite signals when they are sailing on the sea. This paper presents a simple methodology to obtain the dynamic equations of MSTA through Lagrange method, which is fundamental in design of modelbased...

  3. A vortex filament tracking method for the Gross–Pitaevskii model of a superfluid

    International Nuclear Information System (INIS)

    Villois, Alberto; Proment, Davide; Salman, Hayder; Krstulovic, Giorgio

    2016-01-01

    We present an accurate and robust numerical method to track quantised vortex lines in a superfluid described by the Gross–Pitaevskii equation. By utilising the pseudo-vorticity field of the associated complex scalar order parameter of the superfluid, we are able to track the topological defects of the superfluid and reconstruct the vortex lines which correspond to zeros of the field. Throughout, we assume our field is periodic to allow us to make extensive use of the Fourier representation of the field and its derivatives in order to retain spectral accuracy. We present several case studies to test the precision of the method which include the evaluation of the curvature and torsion of a torus vortex knot, and the measurement of the Kelvin wave spectrum of a vortex line and a vortex ring. The method we present makes no a priori assumptions on the geometry of the vortices and is therefore applicable to a wide range of systems such as a superfluid in a turbulent state that is characterised by many vortex rings coexisting with sound waves. This allows us to track the positions of the vortex filaments in a dense turbulent vortex tangle and extract statistical information about the distribution of the size of the vortex rings and the inter-vortex separations. In principle, the method can be extended to track similar topological defects arising in other physical systems. (paper)

  4. Improvement of the physicochemical properties of Co-amorphous naproxen-indomethacin by naproxen-sodium

    DEFF Research Database (Denmark)

    Beyer, Andreas; Grohganz, Holger; Löbmann, Korbinian

    2017-01-01

    Improvement of the physicochemical properties of amorphous active pharmaceutical ingredients (APIs) applying the concept of co-amorphisation is a promising alternative to the use of polymer glass solutions. In co-amorphous systems, the physical stability and the dissolution rate of the involved...... components may be improved in comparison to the respective single amorphous phases. However, for the co-amorphous naproxen-indomethacin model system it has been reported that recrystallization could not be prevented for more than 112days regardless of the applied preparation method and blend ratio...... In the present study, it was thus tested if the physicochemical properties of co-amorphous naproxen-indomethacin could be optimized by incorporation of the naproxen sodium into the system. Three different co-amorphous systems in nine different molar ratios were prepared by quench-cooling: naproxen...

  5. In vivo tracking of neuronal-like cells by magnetic resonance in rabbit models of spinal cord injury

    Science.gov (United States)

    Zhang, Ruiping; Zhang, Kun; Li, Jianding; Liu, Qiang; Xie, Jun

    2013-01-01

    In vitro experiments have demonstrated that neuronal-like cells derived from bone marrow mesenchymal stem cells can survive, migrate, integrate and help to restore the function and behaviors of spinal cord injury models, and that they may serve as a suitable approach to treating spinal cord injury. However, it is very difficult to track transplanted cells in vivo. In this study, we injected superparamagnetic iron oxide-labeled neuronal-like cells into the subarachnoid space in a rabbit model of spinal cord injury. At 7 days after cell transplantation, a small number of dot-shaped low signal intensity shadows were observed in the spinal cord injury region, and at 14 days, the number of these shadows increased on T2-weighted imaging. Perl's Prussian blue staining detected dot-shaped low signal intensity shadows in the spinal cord injury region, indicative of superparamagnetic iron oxide nanoparticle-labeled cells. These findings suggest that transplanted neuronal-like cells derived from bone marrow mesenchymal stem cells can migrate to the spinal cord injury region and can be tracked by magnetic resonance in vivo. Magnetic resonance imaging represents an efficient noninvasive technique for visually tracking transplanted cells in vivo. PMID:25206659

  6. Cumulative approaches to track formation under swift heavy ion (SHI) irradiation: Phenomenological correlation with formation energies of Frenkel pairs

    International Nuclear Information System (INIS)

    Crespillo, M.L.; Agulló-López, F.; Zucchiatti, A.

    2017-01-01

    Highlights: • Extensive survey formation energies Frenkel pairs and electronic stopping thresholds. • Correlation: track formation thresholds and the energies for Frenkel pair formation. • Formation energies Frenkel pairs discussed in relation to the cumulative mechanisms. • Amorphous track formation mechanisms: defect accumulation models versus melting. • Advantages cumulative models to deal with new hot topics: nuclear-electronic synergy. - Abstract: An extensive survey for the formation energies of Frenkel pairs, as representative candidates for radiation-induced point defects, is presented and discussed in relation to the cumulative mechanisms (CM) of track formation in dielectric materials under swift heavy ion (SHI) irradiation. These mechanisms rely on the generation and accumulation of point defects during irradiation followed by collapse of the lattice once a threshold defect concentration is reached. The physical basis of those approaches has been discussed by Fecht as a defect-assisted transition to an amorphous phase. Although a first quantitative analysis of the CM model was previously performed for LiNbO 3 crystals, we have, here, adopted a broader phenomenological approach. It explores the correlation between track formation thresholds and the energies for Frenkel pair formation for a broad range of materials. It is concluded that the threshold stopping powers can be roughly scaled with the energies required to generate a critical Frenkel pair concentration in the order of a few percent of the total atomic content. Finally, a comparison with the predictions of the thermal spike model is discussed within the analytical Szenes approximation.

  7. Cumulative approaches to track formation under swift heavy ion (SHI) irradiation: Phenomenological correlation with formation energies of Frenkel pairs

    Energy Technology Data Exchange (ETDEWEB)

    Crespillo, M.L., E-mail: mcrespil@utk.edu [Centro de Microanálisis de Materiales, CMAM-UAM, Cantoblanco, Madrid 28049 (Spain); Department of Materials Science & Engineering, University of Tennessee, Knoxville, TN 37996 (United States); Agulló-López, F., E-mail: fal@uam.es [Centro de Microanálisis de Materiales, CMAM-UAM, Cantoblanco, Madrid 28049 (Spain); Zucchiatti, A. [Centro de Microanálisis de Materiales, CMAM-UAM, Cantoblanco, Madrid 28049 (Spain)

    2017-03-01

    Highlights: • Extensive survey formation energies Frenkel pairs and electronic stopping thresholds. • Correlation: track formation thresholds and the energies for Frenkel pair formation. • Formation energies Frenkel pairs discussed in relation to the cumulative mechanisms. • Amorphous track formation mechanisms: defect accumulation models versus melting. • Advantages cumulative models to deal with new hot topics: nuclear-electronic synergy. - Abstract: An extensive survey for the formation energies of Frenkel pairs, as representative candidates for radiation-induced point defects, is presented and discussed in relation to the cumulative mechanisms (CM) of track formation in dielectric materials under swift heavy ion (SHI) irradiation. These mechanisms rely on the generation and accumulation of point defects during irradiation followed by collapse of the lattice once a threshold defect concentration is reached. The physical basis of those approaches has been discussed by Fecht as a defect-assisted transition to an amorphous phase. Although a first quantitative analysis of the CM model was previously performed for LiNbO{sub 3} crystals, we have, here, adopted a broader phenomenological approach. It explores the correlation between track formation thresholds and the energies for Frenkel pair formation for a broad range of materials. It is concluded that the threshold stopping powers can be roughly scaled with the energies required to generate a critical Frenkel pair concentration in the order of a few percent of the total atomic content. Finally, a comparison with the predictions of the thermal spike model is discussed within the analytical Szenes approximation.

  8. Tracking sensitive source areas of different weather pollution types using GRAPES-CUACE adjoint model

    Science.gov (United States)

    Wang, Chao; An, Xingqin; Zhai, Shixian; Hou, Qing; Sun, Zhaobin

    2018-02-01

    In this study, the sustained pollution processes were selected during which daily PM2.5 concentration exceeded 75 μg/m3 for three days continuously based on the hourly data of Beijing observation sites from July 2012 to December 2015. Using the China Meteorological Administration (CMA) MICAPS meteorological processing system, synoptic situation during PM2.5 pollution processes was classified into five weather types: low pressure and weak high pressure alternating control, weak high pressure, low pressure control, high rear, and uniform pressure field. Then, we chose the representative pollution cases corresponding to each type, adopted the GRAPES-CUACE adjoint model tracking the sensitive source areas of the five types, and analyzed the critical discharge periods of Beijing and neighboring provinces as well as their contribution to the PM2.5 peak concentration in Beijing. The results showed that the local source plays the main theme in the 30 h before the objective time, and prior to 72 h before the objective time contribution of local sources for the five pollution types are 37.5%, 25.0%, 39.4%, 31.2%, and 42.4%, respectively; the Hebei source contributes constantly in the 57 h ahead of the objective time with the contribution proportion ranging from 37% to 64%; the contribution period and rate of Tianjin and Shanxi sources are shorter and smaller. Based on the adjoint sensitivity analysis, we further discussed the effect of emission reduction control measures in different types, finding that the effect of local source reduction in the first 20 h of the objective time is better, and if the local source is reduced 50% within 72 h before the objective time, the decline rates of PM2.5 in the five types are 11.6%, 9.4%, 13.8%, 9.9% and 15.2% respectively. And the reduction effect of the neighboring sources is better within the 3-57 h before the objective time.

  9. Amorphous nanoparticles — Experiments and computer simulations

    International Nuclear Information System (INIS)

    Hoang, Vo Van; Ganguli, Dibyendu

    2012-01-01

    The data obtained by both experiments and computer simulations concerning the amorphous nanoparticles for decades including methods of synthesis, characterization, structural properties, atomic mechanism of a glass formation in nanoparticles, crystallization of the amorphous nanoparticles, physico-chemical properties (i.e. catalytic, optical, thermodynamic, magnetic, bioactivity and other properties) and various applications in science and technology have been reviewed. Amorphous nanoparticles coated with different surfactants are also reviewed as an extension in this direction. Much attention is paid to the pressure-induced polyamorphism of the amorphous nanoparticles or amorphization of the nanocrystalline counterparts. We also introduce here nanocomposites and nanofluids containing amorphous nanoparticles. Overall, amorphous nanoparticles exhibit a disordered structure different from that of corresponding bulks or from that of the nanocrystalline counterparts. Therefore, amorphous nanoparticles can have unique physico-chemical properties differed from those of the crystalline counterparts leading to their potential applications in science and technology.

  10. Simulation of DNA Damage in Human Cells from Space Radiation Using a Physical Model of Stochastic Particle Tracks and Chromosomes

    Science.gov (United States)

    Ponomarev, Artem; Plante, Ianik; Hada, Megumi; George, Kerry; Wu, Honglu

    2015-01-01

    The formation of double-strand breaks (DSBs) and chromosomal aberrations (CAs) is of great importance in radiation research and, specifically, in space applications. We are presenting a recently developed model, in which chromosomes simulated by NASARTI (NASA Radiation Tracks Image) is combined with nanoscopic dose calculations performed with the Monte-Carlo simulation by RITRACKS (Relativistic Ion Tracks) in a voxelized space. The model produces the number of DSBs, as a function of dose for high-energy iron, oxygen, and carbon ions, and He ions. The combined model calculates yields of radiation-induced CAs and unrejoined chromosome breaks in normal and repair deficient cells. The merged computational model is calibrated using the relative frequencies and distributions of chromosomal aberrations reported in the literature. The model considers fractionated deposition of energy to approximate dose rates of the space flight environment. The merged model also predicts of the yields and sizes of translocations, dicentrics, rings, and more complex-type aberrations formed in the G0/G1 cell cycle phase during the first cell division after irradiation.

  11. Amorphous metal matrix composite ribbons

    International Nuclear Information System (INIS)

    Barczy, P.; Szigeti, F.

    1998-01-01

    Composite ribbons with amorphous matrix and ceramic (SiC, WC, MoB) particles were produced by modified planar melt flow casting methods. Weldability, abrasive wear and wood sanding examinations were carried out in order to find optimal material and technology for elevated wear resistance and sanding durability. The correlation between structure and composite properties is discussed. (author)

  12. Fracture Phenomena in Amorphous Selenium

    DEFF Research Database (Denmark)

    Lindegaard-Andersen, Asger; Dahle, Birgit

    1966-01-01

    Fracture surfaces of amorphous selenium broken in flexure at room temperature have been studied. The fracture velocity was found to vary in different regions of the fracture surface. Peculiar features were observed in a transition zone between fast and slower fracture. In this zone cleavage steps...

  13. MRI-tracking of transplanted human ASC in a SCID mouse model

    Energy Technology Data Exchange (ETDEWEB)

    Siegmund, Birte J.; Kasten, Annika [Department of Oral and Maxillofacial Surgery, Facial Plastic Surgery, Rostock University Medical Center (Germany); Kühn, Jens-Peter [Institute of Diagnostic Radiology and Neuroradiology, Greifswald University Medical Center (Germany); Winter, Karsten [Institute of Anatomy, Faculty of Medicine, University of Leipzig (Germany); Grüttner, Cordula [Micromod Partikeltechnologie GmbH, Rostock (Germany); Frerich, Bernhard, E-mail: bernhard.frerich@med.uni-rostock.de [Department of Oral and Maxillofacial Surgery, Facial Plastic Surgery, Rostock University Medical Center (Germany)

    2017-04-01

    Background: Regarding strategies improving the efficacy of stem cell transplantation in adipose tissue engineering, cell tracking might be useful. Here we report the in vivo tracking of adipose tissue derived stem cells (ASC) by means of nanoparticle labeling and magnetic resonance imaging (MRI). Here we report the in vivo tracking of adipose tissue derived stromal cells (ASC) by means of nanoparticle labeling and magnetic resonance imaging (MRI). Materials and methods: Human ASC were amplified and labeled with two types of magnetic nanoparticles (MNP), BNF starch and nanomag®-D-spio. Adipose tissue constructs were fabricated by seeding collagen scaffolds with labeled and unlabeled ASCs. Constructs were implanted subcutaneously in the back of severe combined immunodeficient (SCID) mice (n =69, group 1: control with cells w/o label, group 2: BNF starch labeled cells, group 3: nanomag®-D-spio labeled cells). MRI scans were performed at 24 hours, four, twelve and 28 days and four months in a 7.1 T animal device. Explanted constructs were analyzed histomorphometrically. Results: MRI scans showed high contrast of the labeled cells in t2-tse-sequence compared to unlabeled controls. Loss of volume of the implants was observed over time due to partial loss for transplanted cells without significant difference (level of significance p<0.017). Compared to histomorphometry, there was found a positiv correlations in measurement of implant size with a significant at day four (correlation coefficient =0.643; p=0.024) and day twelve (correlation coefficient =0.687; p=0.010). Additional Prussian blue stain showed iron in all implants. Significant differences between the three groups (significance level p<0.017) were found after twelve days between control group and group 3 (p=0.008) and after 28 days between control group and group 2 and 3 (p=0.011). Conclusion: Both MNPs might be suitable for tracking of ASC in vivo and show long term stability over 4 months. - Highlights:

  14. Structure of hydrogenated amorphous silicon from ab initio molecular dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Buda, F. (Department of Physics, The Ohio State University, 174 West 18th Avenue, Columbus, Ohio (USA)); Chiarotti, G.L. (International School for Advanced Studies, Strada Costiera 11, I-34014 Trieste (Italy) Laboratorio Tecnologie Avanzate Superfici e Catalisi del Consorzio Interuniversitario Nazionale di Fisica della Materia, Padriciano 99, I-34012 Trieste (Italy)); Car, R. (International School for Advanced Studies, Strada Costiera 11, I-34014 Trieste (Italy) Institut Romard de Recherche Numerique en Physique des Materiaux, CH-1015 Lausanne, Switzerland Department of Condensed Matter Physics, University of Geneva, CH-1211 Geneva (Switzerland)); Parrinello, M. (IBM Research Division, Zurich Research Laboratory, CH-8803 Rueschlikon (Switzerland))

    1991-09-15

    We have generated a model of hydrogenated amorphous silicon by first-principles molecular dynamics. Our results are in good agreement with the available experimental data and provide new insight into the microscopic structure of this material. The calculation lends support to models in which monohydride complexes are prevalent, and indicates a strong tendency of hydrogen to form small clusters.

  15. Thermodynamics, molecular mobility and crystallization kinetics of amorphous griseofulvin.

    Science.gov (United States)

    Zhou, Deliang; Zhang, Geoff G Z; Law, Devalina; Grant, David J W; Schmitt, Eric A

    2008-01-01

    Griseofulvin is a small rigid molecule that shows relatively high molecular mobility and small configurational entropy in the amorphous phase and tends to readily crystallize from both rubbery and glassy states. This work examines the crystallization kinetics and mechanism of amorphous griseofulvin and the quantitative correlation between the rate of crystallization and molecular mobility above and below Tg. Amorphous griseofulvin was prepared by rapidly quenching the melt in liquid N2. The thermodynamics and dynamics of amorphous phase were then characterized using a combination of thermal analysis techniques. After characterization of the amorphous phase, crystallization kinetics above Tg were monitored by isothermal differential scanning calorimetry (DSC). Transformation curves for crystallization fit a second-order John-Mehl-Avrami (JMA) model. Crystallization kinetics below Tg were monitored by powder X-ray diffraction and fit to the second-order JMA model. Activation energies for crystallization were markedly different above and below Tg suggesting a change in mechanism. In both cases molecular mobility appeared to be partially involved in the rate-limiting step for crystallization, but the extent of correlation between the rate of crystallization and molecular mobility was different above and below Tg. A lower extent of correlation below Tg was observed which does not appear to be explained by the molecular mobility alone and the diminishing activation energy for crystallization suggests a change in the mechanism of crystallization.

  16. A Statistical Model of Tropical Cyclone Tracks in the Western North Pacific with ENSO-Dependent Cyclogenesis

    Science.gov (United States)

    Yonekura, Emmi; Hall, Timothy M.

    2011-01-01

    A new statistical model for western North Pacific Ocean tropical cyclone genesis and tracks is developed and applied to estimate regionally resolved tropical cyclone landfall rates along the coasts of the Asian mainland, Japan, and the Philippines. The model is constructed on International Best Track Archive for Climate Stewardship (IBTrACS) 1945-2007 historical data for the western North Pacific. The model is evaluated in several ways, including comparing the stochastic spread in simulated landfall rates with historic landfall rates. Although certain biases have been detected, overall the model performs well on the diagnostic tests, for example, reproducing well the geographic distribution of landfall rates. Western North Pacific cyclogenesis is influenced by El Nino-Southern Oscillation (ENSO). This dependence is incorporated in the model s genesis component to project the ENSO-genesis dependence onto landfall rates. There is a pronounced shift southeastward in cyclogenesis and a small but significant reduction in basinwide annual counts with increasing ENSO index value. On almost all regions of coast, landfall rates are significantly higher in a negative ENSO state (La Nina).

  17. Modelling and Dynamic Simulation of Tracked Forwarder in Adams ATV Module

    OpenAIRE

    Ramachandran, Praveen

    2015-01-01

    Swedish forest industry is relying on the cut-to-length method for logging and there has always been a constant quest to make it more efficient and sustainable. Reduction of forest soil damage and operator vibration dosages are crucial steps that could facilitate meeting the above stated targets. In this context Skogforsk- The Swedish Forest Research Institute has decided to explore the potential usage of caterpillar tracks on conventional wheeled forwarders. An efficient way to perform this ...

  18. Development of a Synthetic Adaptive Neuro-Fuzzy Prediction Model for Tumor Motion Tracking in External Radiotherapy by Evaluating Various Data Clustering Algorithms.

    Science.gov (United States)

    Ghorbanzadeh, Leila; Torshabi, Ahmad Esmaili; Nabipour, Jamshid Soltani; Arbatan, Moslem Ahmadi

    2016-04-01

    In image guided radiotherapy, in order to reach a prescribed uniform dose in dynamic tumors at thorax region while minimizing the amount of additional dose received by the surrounding healthy tissues, tumor motion must be tracked in real-time. Several correlation models have been proposed in recent years to provide tumor position information as a function of time in radiotherapy with external surrogates. However, developing an accurate correlation model is still a challenge. In this study, we proposed an adaptive neuro-fuzzy based correlation model that employs several data clustering algorithms for antecedent parameters construction to avoid over-fitting and to achieve an appropriate performance in tumor motion tracking compared with the conventional models. To begin, a comparative assessment is done between seven nuero-fuzzy correlation models each constructed using a unique data clustering algorithm. Then, each of the constructed models are combined within an adaptive sevenfold synthetic model since our tumor motion database has high degrees of variability and that each model has its intrinsic properties at motion tracking. In the proposed sevenfold synthetic model, best model is selected adaptively at pre-treatment. The model also updates the steps for each patient using an automatic model selectivity subroutine. We tested the efficacy of the proposed synthetic model on twenty patients (divided equally into two control and worst groups) treated with CyberKnife synchrony system. Compared to Cyberknife model, the proposed synthetic model resulted in 61.2% and 49.3% reduction in tumor tracking error in worst and control group, respectively. These results suggest that the proposed model selection program in our synthetic neuro-fuzzy model can significantly reduce tumor tracking errors. Numerical assessments confirmed that the proposed synthetic model is able to track tumor motion in real time with high accuracy during treatment. © The Author(s) 2015.

  19. “How to Track Baby Feedings” Penerapan Model Dokumentasi Dengan Menggunakan Software Sebagai Upaya Meningkatkan Pertumbuhan Dan Perkembangan Pada Bayi

    OpenAIRE

    Dwi Susanti, Henny

    2014-01-01

    “How To Track Baby Feedings” Penerapan Model Dokumentasi Dengan Menggunakan Software Sebagai Upaya Meningkatkan Pertumbuhan dan Perkembangan Pada Bayi“How to Track Baby Feedings” Implementation Documentation Model by Using Software as an Effort to Improve Growth and Development in InfantsHenny Dwi SusantiFakultas Ilmu Kesehatan, Universitas Muhammadiyah MalangJl. Bendungan Sutami 188A Malang 65145E-mail : Pertumbuhan adalah bertambahnya ukuran tubuh, sedangkan perk...

  20. Mathematical Model of Movement of the Observation and Tracking Head of an Unmanned Aerial Vehicle Performing Ground Target Search and Tracking

    Directory of Open Access Journals (Sweden)

    Izabela Krzysztofik

    2014-01-01

    Full Text Available The paper presents the kinematics of mutual movement of an unmanned aerial vehicle (UAV and a ground target. The controlled observation and tracking head (OTH is a device responsible for observing the ground, searching for a ground target, and tracking it. The preprogrammed movement of the UAV on the circle with the simultaneous movement of the head axis on Archimedes’ spiral during searching for a ground target, both fixed (bunkers, rocket missiles launching positions, etc. and movable (tanks, infantry fighting vehicles, etc., is considered. Dynamics of OTH during the performance of the above mentioned activities is examined. Some research results are presented in a graphical form.

  1. Particle tracking

    CERN Document Server

    Safarík, K; Newby, J; Sørensen, P

    2002-01-01

    In this lecture we will present a short historical overview of different tracking detectors. Then we will describe currently used gaseous and silicon detectors and their performance. In the second part we will discuss how to estimate tracking precision, how to design a tracker and how the track finding works. After a short description of the LHC the main attention is drawn to the ALICE experiment since it is dedicated to study new states in hadronic matter at the LHC. The ALICE tracking procedure is discussed in detail. A comparison to the tracking in ATLAS, CMS and LHCb is given. (5 refs).

  2. Modeling Sediment Transport Using a Lagrangian Particle Tracking Algorithm Coupled with High-Resolution Large Eddy Simulations: a Critical Analysis of Model Limits and Sensitivity

    Science.gov (United States)

    Garcia, M. H.

    2016-12-01

    Modeling Sediment Transport Using a Lagrangian Particle Tracking Algorithm Coupled with High-Resolution Large Eddy Simulations: a Critical Analysis of Model Limits and Sensitivity Som Dutta1, Paul Fischer2, Marcelo H. Garcia11Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, Il, 61801 2Department of Computer Science and Department of MechSE, University of Illinois at Urbana-Champaign, Urbana, Il, 61801 Since the seminal work of Niño and Garcia [1994], one-way coupled Lagrangian particle tracking has been used extensively for modeling sediment transport. Over time, the Lagrangian particle tracking method has been coupled with Eulerian flow simulations, ranging from Reynolds Averaged Navier-Stokes (RANS) based models to Detached Eddy Simulations (DES) [Escauriaza and Sotiropoulos, 2011]. Advent of high performance computing (HPC) platforms and faster algorithms have resulted in the work of Dutta et al. [2016], where Lagrangian particle tracking was coupled with high-resolution Large Eddy Simulations (LES) to model the complex and highly non-linear phenomenon of Bulle-Effect at diversions. Despite all the advancements in using Lagrangian particle tracking, there has not been a study that looks in detail at the limits of the model in the context of sediment transport, and also analyzes the sensitivity of the various force formulation in the force balance equation of the particles. Niño and Garcia [1994] did a similar analysis, but the vertical flow velocity distribution was modeled as the log-law. The current study extends the analysis by modeling the flow using high-resolution LES at a Reynolds number comparable to experiments of Niño et al. [1994]. Dutta et al., (2016), Large Eddy Simulation (LES) of flow and bedload transport at an idealized 90-degree diversion: insight into Bulle-Effect, River Flow 2016 - Constantinescu, Garcia & Hanes (Eds), Taylor & Francis Group, London, 101-109. Escauriaza and Sotiropoulos

  3. Generating MnO2 nanoparticles using simulated amorphization and recrystallization

    CSIR Research Space (South Africa)

    Sayle, TXT

    2005-09-21

    Full Text Available Models of MnO2 nanoparticles, with full atomistic detail, have been generated using a simulated amorphization and recrystallization strategy. In particular, a 25,000-atom "cube" of MnO2 was amorphized (tension-induced) under molecular dynamics (MD...

  4. Track inspection planning and risk measurement analysis.

    Science.gov (United States)

    2014-11-01

    This project models track inspection operations on a railroad network and discusses how the inspection results can : be used to measure the risk of failure on the tracks. In particular, the inspection times of the tracks, inspection frequency of the ...

  5. A discrete time-varying internal model-based approach for high precision tracking of a multi-axis servo gantry.

    Science.gov (United States)

    Zhang, Zhen; Yan, Peng; Jiang, Huan; Ye, Peiqing

    2014-09-01

    In this paper, we consider the discrete time-varying internal model-based control design for high precision tracking of complicated reference trajectories generated by time-varying systems. Based on a novel parallel time-varying internal model structure, asymptotic tracking conditions for the design of internal model units are developed, and a low order robust time-varying stabilizer is further synthesized. In a discrete time setting, the high precision tracking control architecture is deployed on a Voice Coil Motor (VCM) actuated servo gantry system, where numerical simulations and real time experimental results are provided, achieving the tracking errors around 3.5‰ for frequency-varying signals. Copyright © 2014 ISA. Published by Elsevier Ltd. All rights reserved.

  6. Amorphous computing in the presence of stochastic disturbances.

    Science.gov (United States)

    Chu, Dominique; Barnes, David J; Perkins, Samuel

    2014-11-01

    Amorphous computing is a non-standard computing paradigm that relies on massively parallel execution of computer code by a large number of small, spatially distributed, weakly interacting processing units. Over the last decade or so, amorphous computing has attracted a great deal of interest both as an alternative model of computing and as an inspiration to understand developmental biology. A number of algorithms have been developed that can take advantage of the massive parallelism of this computing paradigm to solve specific problems. One of the interesting properties of amorphous computers is that they are robust with respect to the loss of individual processing units, in the sense that a removal of some of them should not impact on the computation as a whole. However, much less understood is to what extent amorphous computers are robust with respect to minor disturbances to the individual processing units, such as random motion or occasional faulty computation short of total component failure. In this article we address this question. As an example problem we choose an algorithm to calculate a straight line between two points. Using this example, we find that amorphous computers are not in general robust with respect to Brownian motion and noise, but we find strategies that restore reliable computation even in their presence. We will argue that these strategies are generally applicable and not specific to the particular AC we consider, or even specific to electronic computers. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  7. Amorphous gauge glass theory

    International Nuclear Information System (INIS)

    Nielsen, H.B.; Bennett, D.L.

    1987-08-01

    Assuming that a lattice gauge theory describes a fundamental attribute of Nature, it should be pointed out that such a theory in the form of a gauge glass is a weaker assumption than a regular lattice model in as much as it is not constrained by the imposition of translational invariance; translational invariance is, however, recovered approximately in the long wavelength or continuum limit. (orig./WL)

  8. Modeling of reactive transport with particle tracking and kernel density estimators

    OpenAIRE

    Rahbaralam, Maryam

    2018-01-01

    Random walk particle tracking methods are a computationally efficient family of methods to solve reactive transport problems. While the number of particles in most realistic applications is in the order of 10^6 - 10^9, the number of reactive molecules even in diluted systems might be in the order of fractions of the Avogadro number. Thus, each particle actually represents a group of potentially reactive molecules. The use of a low number of particles may result not only in loss of accuracy, b...

  9. A Generic Model Based Tracking Controller for Hydraulic Valve-Cylinder Drives

    DEFF Research Database (Denmark)

    Hansen, Anders Hedegaard; Schmidt, Lasse; Pedersen, Henrik Clemmensen

    2016-01-01

    The control of hydraulic valve-cylinder drives is still an active subject of research, and various linear and particularly nonlinear approaches has been proposed, especially in the last two-three decades. In many cases the proposed controllers appear to produce excellent tracking ability due...... based linear analysis tools such as bode plots, root loci etc. in order for the controller parameterizations to be realized. However, the analytic approach presented takes offset in such analyzes, but in a generalized fashion. The proposed control structures are focused on industrial applicability...

  10. Amorphous metal based nanoelectromechanical switch

    KAUST Repository

    Mayet, Abdulilah M.

    2013-04-01

    Nanoelectromechanical (NEM) switch is an interesting ultra-low power option which can operate in the harsh environment and can be a complementary element in complex digital circuitry. Although significant advancement is happening in this field, report on ultra-low voltage (pull-in) switch which offers high switching speed and area efficiency is yet to be made. One key challenge to achieve such characteristics is to fabricate nano-scale switches with amorphous metal so the shape and dimensional integrity are maintained to achieve the desired performance. Therefore, we report a tungsten alloy based amorphous metal with fabrication process development of laterally actuated dual gated NEM switches with 100 nm width and 200 nm air-gap to result in <5 volts of actuation voltage (Vpull-in). © 2013 IEEE.

  11. Uranium incorporation into amorphous silica.

    Science.gov (United States)

    Massey, Michael S; Lezama-Pacheco, Juan S; Nelson, Joey M; Fendorf, Scott; Maher, Kate

    2014-01-01

    High concentrations of uranium are commonly observed in naturally occurring amorphous silica (including opal) deposits, suggesting that incorporation of U into amorphous silica may represent a natural attenuation mechanism and promising strategy for U remediation. However, the stability of uranium in opaline silicates, determined in part by the binding mechanism for U, is an important factor in its long-term fate. U may bind directly to the opaline silicate matrix, or to materials such as iron (hydr)oxides that are subsequently occluded within the opal. Here, we examine the coordination environment of U within opaline silica to elucidate incorporation mechanisms. Precipitates (with and without ferrihydrite inclusions) were synthesized from U-bearing sodium metasilicate solutions, buffered at pH ∼ 5.6. Natural and synthetic solids were analyzed with X-ray absorption spectroscopy and a suite of other techniques. In synthetic amorphous silica, U was coordinated by silicate in a double corner-sharing coordination geometry (Si at ∼ 3.8-3.9 Å) and a small amount of uranyl and silicate in a bidentate, mononuclear (edge-sharing) coordination (Si at ∼ 3.1-3.2 Å, U at ∼ 3.8-3.9 Å). In iron-bearing synthetic solids, U was adsorbed to iron (hydr)oxide, but the coordination environment also contained silicate in both edge-sharing and corner-sharing coordination. Uranium local coordination in synthetic solids is similar to that of natural U-bearing opals that retain U for millions of years. The stability and extent of U incorporation into opaline and amorphous silica represents a long-term repository for U that may provide an alternative strategy for remediation of U contamination.

  12. A Position Controller Model on Color-Based Object Tracking using Fuzzy Logic

    Science.gov (United States)

    Cahyo Wibowo, Budi; Much Ibnu Subroto, Imam; Arifin, Bustanul

    2017-04-01

    Robotics vision is applying technology on the camera to view the environmental conditions as well as the function of the human eye. Colour object tracking system is one application of robotics vision technology with the ability to follow the object being detected. Several methods have been used to generate a good response position control, but most are still using conventional control approach. Fuzzy logic which includes several step of which is to determine the value of crisp input must be fuzzification. The output of fuzzification is forwarded to the process of inference in which there are some fuzzy logic rules. The inference output forwarded to the process of defuzzification to be transformed into outputs (crisp output) to drive the servo motors on the X-axis and Y-axis. Fuzzy logic control is applied to the color-based object tracking system, the system is successful to follow a moving object with average speed of 7.35 cm/s in environments with 117 lux light intensity.

  13. An Improved Mixture-of-Gaussians Background Model with Frame Difference and Blob Tracking in Video Stream

    Directory of Open Access Journals (Sweden)

    Li Yao

    2014-01-01

    Full Text Available Modeling background and segmenting moving objects are significant techniques for computer vision applications. Mixture-of-Gaussians (MoG background model is commonly used in foreground extraction in video steam. However considering the case that the objects enter the scenery and stay for a while, the foreground extraction would fail as the objects stay still and gradually merge into the background. In this paper, we adopt a blob tracking method to cope with this situation. To construct the MoG model more quickly, we add frame difference method to the foreground extracted from MoG for very crowded situations. What is more, a new shadow removal method based on RGB color space is proposed.

  14. Tracking the MSL-SAM methane detection source location Through Mars Regional Atmospheric Modeling System (MRAMS)

    Science.gov (United States)

    Pla-García, Jorge

    2016-04-01

    1. Introduction: The putative in situ detection of methane by Sample Analysis at Mars (SAM) instrument suite on Curiosi-ty at Gale crater has garnered significant attention because of the potential implications for the presence of geological methane sources or indigenous Martian organisms [1, 2]. SAM reported detection of back-ground levels of atmospheric methane of mean value 0.69±0.25 parts per billion by volume (ppbv) at the 95% confidence interval (CI). Additionally, in four sequential measurements spanning a 60-sol period, SAM observed elevated levels of methane of 7.2±2.1 ppbv (95% CI), implying that Mars is episodically producing methane from an additional unknown source. There are many major unresolved questions regard-ing this detection: 1) What are the potential sources of the methane release? 2) What causes the rapid decrease in concentration? and 3) Where is the re-lease location? 4) How spatially extensive is the re-lease? 5) For how long is CH4 released? Regarding the first question, the source of methane, is so far not identified. It could be related with geo-logical process like methane release from clathrates [3], serpentinisation [4] and volcanism [5]; or due to biological activity from methanogenesis [6]. To answer the second question, the rapid decrease in concentration, it is important to note that the photo-chemical lifetime of methane is of order 100 years, much longer than the atmospheric mixing time scale, and thus the gas should tend to be well mixed except near a source or shortly after an episodic release. The observed spike of 7 ppb from the background of System (MRAMS). The model was focused on rover locations using nested grids with a spacing of 330 meters on the in-nermost grid that is centered over the landing [8, 9]. MRAMS is ideally suited for this investigation; the model is explicitly designed to simulate Mars' at-mospheric circulations at the mesoscale and smaller with realistic, high-resolution surface properties [10, 11

  15. Diffusion in amorphous media

    Science.gov (United States)

    Iotov, Mihail S.

    The goals of this research are twofold: First, to develop methods and tools for studying problems in chemistry, material science and biology, as well as accurate prediction of the properties of structures and materials of importance to those fields. Second, use those tools to apply the methods to practical problems. In terms of methodology development this thesis focuses on two topics: One: Development of a massively parallel computer program to perform electronic, atomic, molecular levels simulations of problems in chemistry, material science and biology. This computer program uses existing and emerging hardware platforms and parallel tools and is based on decades long research in computer modeling and algorithms. We report on that development in Chapter 3. Two: Development of tools for Molecular Dynamics simulation and methods and tools for course-grained meso-scale modeling of transport properties and especially diffusion of gas penetrants in polymers. We have formulated a new method for extracting coarse-grained information from short (0.2-0.5 nanoseconds [ns]) MD simulations and use this in a meso-scale simulation to calculate diffusion constants in polymer matrices. This is a grid-based method, which calculates the average probability of each grid point of being a void and performs constrained and biased Monte Carlo (MC) dynamics to reach much longer time regimes than possible in MD. The MC method mimics the three regimes of mean square deviation (MSD) behavior seen in MD, thus accounting for the proper mobility of the voids and the compressibility of the polymer matrix. Theoretical discussions and justification for the method is presented in chapter 6. Initial results on He diffusion in a low-density polyethylene (PE) matrix are presented in chapter 7. The behavior at different temperatures follows closely the trend observed from calibrating long term MD for this particular system.

  16. Tumor Tracking Method Based on a Deformable 4D CT Breathing Motion Model Driven by an External Surface Surrogate

    Energy Technology Data Exchange (ETDEWEB)

    Fassi, Aurora, E-mail: aurora.fassi@mail.polimi.it [Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Milano (Italy); Schaerer, Joël; Fernandes, Mathieu [CREATIS, CNRS UMR 5220, INSERM U1044, Université Lyon 1, INSA-Lyon, Villeurbanne (France); Department of Radiotherapy, Centre Léon Bérard, Lyon (France); Riboldi, Marco [Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Milano (Italy); Bioengineering Unit, CNAO Foundation, Pavia (Italy); Sarrut, David [CREATIS, CNRS UMR 5220, INSERM U1044, Université Lyon 1, INSA-Lyon, Villeurbanne (France); Department of Radiotherapy, Centre Léon Bérard, Lyon (France); Baroni, Guido [Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Milano (Italy); Bioengineering Unit, CNAO Foundation, Pavia (Italy)

    2014-01-01

    Purpose: To develop a tumor tracking method based on a surrogate-driven motion model, which provides noninvasive dynamic localization of extracranial targets for the compensation of respiration-induced intrafraction motion in high-precision radiation therapy. Methods and Materials: The proposed approach is based on a patient-specific breathing motion model, derived a priori from 4-dimensional planning computed tomography (CT) images. Model parameters (respiratory baseline, amplitude, and phase) are retrieved and updated at each treatment fraction according to in-room radiography acquisition and optical surface imaging. The baseline parameter is adapted to the interfraction variations obtained from the daily cone beam (CB) CT scan. The respiratory amplitude and phase are extracted from an external breathing surrogate, estimated from the displacement of the patient thoracoabdominal surface, acquired with a noninvasive surface imaging device. The developed method was tested on a database of 7 lung cancer patients, including the synchronized information on internal and external respiratory motion during a CBCT scan. Results: About 30 seconds of simultaneous acquisition of CBCT and optical surface images were analyzed for each patient. The tumor trajectories identified in CBCT projections were used as reference and compared with the target trajectories estimated from surface displacement with the a priori motion model. The resulting absolute differences between the reference and estimated tumor motion along the 2 image dimensions ranged between 0.7 and 2.4 mm; the measured phase shifts did not exceed 7% of the breathing cycle length. Conclusions: We investigated a tumor tracking method that integrates breathing motion information provided by the 4-dimensional planning CT with surface imaging at the time of treatment, representing an alternative approach to point-based external–internal correlation models. Although an in-room radiograph-based assessment of the

  17. Thermochemical, structural and electronic properties of amorphous oxides, nitrides and sulfides

    Science.gov (United States)

    Zawadzki, Pawel; Lany, Stephan

    2015-03-01

    Amorphous thin films materials become increasingly important components of many functional devices such as thin film displays, photovoltaic cells or thin film transistors. Due to lack of grain boundaries, they have superior uniformity and smoothest, flexibility and corrosion resistance. Amorphous thin films are typically prepared using physical vapor deposition (PVD) techniques at temperatures well below the melting point of deposited material (<0.2Tm). Computational models of amorphous structures, however, are almost elusively constructed from a high temperature equilibrated crystal melt using simulated annealing (SA) protocol. To account for low temperature growth conditions of amorphous thin films we recently developed a new simulation technique. The method, kinetically limited minimization (KLM), starts from a randomly initialized structure and minimizes the total energy in a number of local structural perturbation-relaxation events. We apply KLM to model amorphous structures of 20 binary oxides, nitrides and sulfides and compare their thermochemical, structural and electronic properties.

  18. The role of fluoride and casein phosphopeptide/amorphous calcium phosphate in the prevention of erosive/abrasive wear in an in vitro model using hydrochloric acid.

    Science.gov (United States)

    Wegehaupt, Florian J; Attin, T

    2010-01-01

    To investigate the effect of various fluoride compounds and casein phosphopeptide/amorphous calcium phosphate (CPP-ACP) on the reduction of erosive/abrasive tooth wear. Forty enamel samples were prepared from bovine lower incisors, stratified and allocated to 4 groups (1-4). Samples in group 1 remained untreated and served as negative controls. The test samples were treated for 2 min/day as follows: group 2 amine/sodium fluoride gel (pH 4.8; 12,500 ppm), group 3 sodium fluoride gel (pH 7.1; 12,500 ppm) and group 4 CPP-ACP-containing mousse. De- and remineralization cycling was performed for 20 days with 6 erosive attacks for 20 s with HCl (pH 3.0) per day. Samples were stored in artificial saliva between cycles and overnight. Toothbrushing (15 s; 60 strokes/min; load 2.5 N) with a toothpaste slurry was performed each day before the first and 1 h after the last erosive exposure. Tooth wear was measured by comparing baseline surface profiles with the corresponding posttreatment profiles. Tooth wear was significantly reduced in groups 2 and 3 compared with group 1, while the enamel loss of group 4 was not significantly lower compared to the negative control group 1. Between the fluoride groups 2 and 3, no significant difference in tooth wear was recorded. Erosive/abrasive tooth wear under the conditions used could be reduced significantly by the daily application of fluoride gels, irrespective of the fluoride compound, while the application of CPP-ACP-containing mousse was less effective. Copyright 2010 S. Karger AG, Basel.

  19. Water migration mechanisms in amorphous powder material and related agglomeration

    NARCIS (Netherlands)

    Renzetti, S.; Voogt, J.A.; Oliver, L.; Meinders, M.B.J.

    2012-01-01

    The agglomeration phenomenon of amorphous particulate material is a major problem in the food industry. Currently, the glass transition temperature (Tg) is used as a fundamental parameter to describe and control agglomeration. Models are available that describe the kinetics of the agglomeration

  20. Local atomic environment in amorphous Ge15Te85

    Science.gov (United States)

    Jóvári, P.; Kaban, I.; Hoyer, W.; Delaplane, R. G.; Wannberg, A.

    2005-03-01

    The structure of amorphous Ge15Te85 has been studied by neutron and x-ray diffraction. Experimental data have been modelled simultaneously with the reverse Monte Carlo simulation method. The contrast between structure factors together with the application of some plausible physical constraints allowed the separation of the three partial pair correlation functions and determination of Ge and Te local environment.

  1. Detection of charged particles in amorphous silicon layers

    International Nuclear Information System (INIS)

    Perez-Mendez, V.; Morel, J.; Kaplan, S.N.; Street, R.A.

    1986-02-01

    The successful development of radiation detectors made from amorphous silicon could offer the possibility for relatively easy construction of large area position-sensitive detectors. We have conducted a series of measurements with prototype detectors, on signals derived from alpha particles. The measurement results are compared with simple model calculations, and projections are made of potential applications in high-energy and nuclear physics

  2. Theory of structure and properties of hydrogenated amorphous silicon

    Energy Technology Data Exchange (ETDEWEB)

    Chiarotti, G.L.; Car, R. (International School of Advanced Studies, Trieste (Italy) Interuniversitario Nazionale di Fisica della Materia (INFM), Trieste (Italy). Lab. Tecnologie Avanzate Superfici e Catalisi); Buda, F. (International School of Advanced Studies, Trieste (Italy) Ohio State Univ., Columbus, OH (USA). Dept. of Physics); Parrinello, M. (International School of Advanced Studies, Trieste

    1990-01-01

    We have generated a computer model of hydrogenated amorphous silicon by first-principles molecular dynamics. Our results are in good agreement with the available experimental data, and provide new insight into the microscopic structure of this material. This should lead to a better understanding of the hydrogenation process. 13 refs., 2 figs.

  3. Predicting and understanding Korean high school students' science-track choice: Testing the theory of reasoned action by structural equation modeling

    Science.gov (United States)

    Myeong, Jeon-Ok; Crawley, Frank E.

    The theory of reasoned action (Ajzen & Fishbein, 1980; Fishbein & Ajzen, 1975) was used to predict and understand Korean high school students' track choice for college entrance. First-year high school students (N = 665) from four representative regions of Korea participated in the study. The survey instruments were questionnaires developed according to the guidelines of the TRA. The target behavior of interest in this study was Korean students' choice of the science track when they completed the track application forms during the first year of high school. Predictors included TRA model and external variables. Multiple regression and the structural equation modeling with LISREL (Jöreskog & Sörbom, 1986) were used to analyze the data. The TRA was found to be applicable for understanding and predicting track choice, with minor modifications. Subjective norm was found to exert a direct influence on personal beliefs and the target behavior.

  4. Traveling cluster approximation for uncorrelated amorphous systems

    International Nuclear Information System (INIS)

    Kaplan, T.; Sen, A.K.; Gray, L.J.; Mills, R.

    1985-01-01

    In this paper, the authors apply the TCA concepts to spatially disordered, uncorrelated systems (e.g., fluids or amorphous metals without short-range order). This is the first approximation scheme for amorphous systems that takes cluster effects into account while preserving the Herglotz property for any amount of disorder. They have performed some computer calculations for the pair TCA, for the model case of delta-function potentials on a one-dimensional random chain. These results are compared with exact calculations (which, in principle, taken into account all cluster effects) and with the CPA, which is the single-site TCA. The density of states for the pair TCA clearly shows some improvement over the CPA, and yet, apparently, the pair approximation distorts some of the features of the exact results. They conclude that the effects of large clusters are much more important in an uncorrelated liquid metal than in a substitutional alloy. As a result, the pair TCA, which does quite a nice job for alloys, is not adequate for the liquid. Larger clusters must be treated exactly, and therefore an n-TCA with n > 2 must be used

  5. Superparamagnetic iron oxide nanoparticles as a means to track mesenchymal stem cells in a large animal model of tendon injury.

    Science.gov (United States)

    Scharf, Alexandra; Holmes, Shannon; Thoresen, Merrilee; Mumaw, Jennifer; Stumpf, Alaina; Peroni, John

    2015-01-01

    The goal of this study was to establish an SPIO-based cell-tracking method in an ovine model of tendonitis and to determine if this method may be useful for further study of cellular therapies in tendonitis in vivo. Functional assays were performed on labeled and unlabeled cells to ensure that no significant changes were induced by intracellular SPIOs. Following biosafety validation, tendon lesions were mechanically (n = 4) or chemically (n = 4) induced in four sheep and scanned ex vivo at 7 and 14 days to determine the presence and distribution of intralesional cells. Ovine MSCs labeled with 50 µg SPIOs/mL remained viable, proliferate, and undergo tri-lineage differentiation (p cell numbers as low as 10 000 and in volumetric distributions as low as 100 000 cells/mL. Cells remained detectable by MRI at 7 days, as confirmed by correlative histology for dually labeled SPIO+/GFP+ cells. Histological evidence at 14 days suggested that SPIO particles remained embedded in tissue, providing MRI signal, although cells were no longer present. SPIO labeling has proven to be an effective method for cell tracking for a large animal model of tendon injury for up to 7 days post-injection. The data obtained in this study justify further investigation into the effects of MSC survival and migration on overall tendon healing and tissue regeneration. Copyright © 2015 John Wiley & Sons, Ltd.

  6. Comparison of the Dynamic Response of One- and Two-Dimensional Models for an Embedded Railway Track to a Moving Load,

    NARCIS (Netherlands)

    Shamalta, M.; Metrikine, A.V.

    2002-01-01

    In this paper, the steady-state response of an embedded track to the axle loading of a moving train is studied theoretically using two models. The first and the second models are one-dimensional (1D) and two-dimensional (2D), respectively, and differ by the fact that the latter model accounts for

  7. Electronic excitations in metallic systems: from defect annihilation to track formation

    International Nuclear Information System (INIS)

    Dunlop, A.; Lesueur, D.

    1991-01-01

    This paper presents an overview of the effects of high electronic energy deposition in metallic targets irradiated with GeV heavy ions. The main result of these investigations is that high electronic excitations lead to various and sometimes conflicting effects according to the nature of the target: - partial annealing of the defects induced by elastic collisions, - creation of additional disorder, - phase transformation (tracks formation and amorphization), - anisotropic growth. These different effects of high electronic energy deposition in metallic targets are probably manifestations at various degrees of the same basic energy transfer process between the excited electrons and the target atoms. Up to now no theoretical model explains these effects. 24 refs

  8. Tracking control of nonlinear lumped mechanical continuous-time systems: A model-based iterative learning approach

    Science.gov (United States)

    Smolders, K.; Volckaert, M.; Swevers, J.

    2008-11-01

    This paper presents a nonlinear model-based iterative learning control procedure to achieve accurate tracking control for nonlinear lumped mechanical continuous-time systems. The model structure used in this iterative learning control procedure is new and combines a linear state space model and a nonlinear feature space transformation. An intuitive two-step iterative algorithm to identify the model parameters is presented. It alternates between the estimation of the linear and the nonlinear model part. It is assumed that besides the input and output signals also the full state vector of the system is available for identification. A measurement and signal processing procedure to estimate these signals for lumped mechanical systems is presented. The iterative learning control procedure relies on the calculation of the input that generates a given model output, so-called offline model inversion. A new offline nonlinear model inversion method for continuous-time, nonlinear time-invariant, state space models based on Newton's method is presented and applied to the new model structure. This model inversion method is not restricted to minimum phase models. It requires only calculation of the first order derivatives of the state space model and is applicable to multivariable models. For periodic reference signals the method yields a compact implementation in the frequency domain. Moreover it is shown that a bandwidth can be specified up to which learning is allowed when using this inversion method in the iterative learning control procedure. Experimental results for a nonlinear single-input-single-output system corresponding to a quarter car on a hydraulic test rig are presented. It is shown that the new nonlinear approach outperforms the linear iterative learning control approach which is currently used in the automotive industry on durability test rigs.

  9. MUICYCL and MUIFAP: models tracking minor uranium isotopes in the nuclear fuel cycle

    Energy Technology Data Exchange (ETDEWEB)

    Blum, S.R.; McLaren, R.A.

    1979-10-01

    Two computer programs have been written to provide information on the buildup of minor uranium isotopes in the nuclear fuel cycle. The Minor Uranium Isotope Cycle Program, MUICYCL, tracks fuel through a multiyear campaign cycle of enrichment, reactor burnup, reprocessing, enrichment, etc. MUICYCL facilities include preproduction stockpiles, U/sup 235/ escalation, and calculation of losses. The Minor Uranium Isotope Flowsheet Analyzer Program, MUIFAP, analyzes one minor isotope in one year of an enrichment operation. The formulation of the enrichment cascade, reactors, and reprocessing facility is presented. Input and output descriptions and sample cases are presented. The programs themselves are documented by short descriptions of each routine, flowcharts, definitions of common blocks and variables, and internal documentation. The programs are written in FORTRAN for use in batch mode.

  10. MUICYCL and MUIFAP: models tracking minor uranium isotopes in the nuclear fuel cycle

    International Nuclear Information System (INIS)

    Blum, S.R.; McLaren, R.A.

    1979-10-01

    Two computer programs have been written to provide information on the buildup of minor uranium isotopes in the nuclear fuel cycle. The Minor Uranium Isotope Cycle Program, MUICYCL, tracks fuel through a multiyear campaign cycle of enrichment, reactor burnup, reprocessing, enrichment, etc. MUICYCL facilities include preproduction stockpiles, U 235 escalation, and calculation of losses. The Minor Uranium Isotope Flowsheet Analyzer Program, MUIFAP, analyzes one minor isotope in one year of an enrichment operation. The formulation of the enrichment cascade, reactors, and reprocessing facility is presented. Input and output descriptions and sample cases are presented. The programs themselves are documented by short descriptions of each routine, flowcharts, definitions of common blocks and variables, and internal documentation. The programs are written in FORTRAN for use in batch mode

  11. Volume-weighted particle-tracking method for solute-transport modeling; Implementation in MODFLOW–GWT

    Science.gov (United States)

    Winston, Richard B.; Konikow, Leonard F.; Hornberger, George Z.

    2018-02-16

    In the traditional method of characteristics for groundwater solute-transport models, advective transport is represented by moving particles that track concentration. This approach can lead to global mass-balance problems because in models of aquifers having complex boundary conditions and heterogeneous properties, particles can originate in cells having different pore volumes and (or) be introduced (or removed) at cells representing fluid sources (or sinks) of varying strengths. Use of volume-weighted particles means that each particle tracks solute mass. In source or sink cells, the changes in particle weights will match the volume of water added or removed through external fluxes. This enables the new method to conserve mass in source or sink cells as well as globally. This approach also leads to potential efficiencies by allowing the number of particles per cell to vary spatially—using more particles where concentration gradients are high and fewer where gradients are low. The approach also eliminates the need for the model user to have to distinguish between “weak” and “strong” fluid source (or sink) cells. The new model determines whether solute mass added by fluid sources in a cell should be represented by (1) new particles having weights representing appropriate fractions of the volume of water added by the source, or (2) distributing the solute mass added over all particles already in the source cell. The first option is more appropriate for the condition of a strong source; the latter option is more appropriate for a weak source. At sinks, decisions whether or not to remove a particle are replaced by a reduction in particle weight in proportion to the volume of water removed. A number of test cases demonstrate that the new method works well and conserves mass. The method is incorporated into a new version of the U.S. Geological Survey’s MODFLOW–GWT solute-transport model.

  12. Colloidal Photoluminescent Amorphous Porous Silicon, Methods Of Making Colloidal Photoluminescent Amorphous Porous Silicon, And Methods Of Using Colloidal Photoluminescent Amorphous Porous Silicon

    KAUST Repository

    Chaieb, Sahraoui

    2015-04-09

    Embodiments of the present disclosure provide for a colloidal photoluminescent amorphous porous silicon particle suspension, methods of making a colloidal photoluminescent amorphous porous silicon particle suspension, methods of using a colloidal photoluminescent amorphous porous silicon particle suspension, and the like.

  13. Robust model reference adaptive output feedback tracking for uncertain linear systems with actuator fault based on reinforced dead-zone modification.

    Science.gov (United States)

    Bagherpoor, H M; Salmasi, Farzad R

    2015-07-01

    In this paper, robust model reference adaptive tracking controllers are considered for Single-Input Single-Output (SISO) and Multi-Input Multi-Output (MIMO) linear systems containing modeling uncertainties, unknown additive disturbances and actuator fault. Two new lemmas are proposed for both SISO and MIMO, under which dead-zone modification rule is improved such that the tracking error for any reference signal tends to zero in such systems. In the conventional approach, adaption of the controller parameters is ceased inside the dead-zone region which results tracking error, while preserving the system stability. In the proposed scheme, control signal is reinforced with an additive term based on tracking error inside the dead-zone which results in full reference tracking. In addition, no Fault Detection and Diagnosis (FDD) unit is needed in the proposed approach. Closed loop system stability and zero tracking error are proved by considering a suitable Lyapunov functions candidate. It is shown that the proposed control approach can assure that all the signals of the close loop system are bounded in faulty conditions. Finally, validity and performance of the new schemes have been illustrated through numerical simulations of SISO and MIMO systems in the presence of actuator faults, modeling uncertainty and output disturbance. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

  14. Extracting Crystal Chemistry from Amorphous Carbon Structures.

    Science.gov (United States)

    Deringer, Volker L; Csányi, Gábor; Proserpio, Davide M

    2017-04-19

    Carbon allotropes have been explored intensively by ab initio crystal structure prediction, but such methods are limited by the large computational cost of the underlying density functional theory (DFT). Here we show that a novel class of machine-learning-based interatomic potentials can be used for random structure searching and readily predicts several hitherto unknown carbon allotropes. Remarkably, our model draws structural information from liquid and amorphous carbon exclusively, and so does not have any prior knowledge of crystalline phases: it therefore demonstrates true transferability, which is a crucial prerequisite for applications in chemistry. The method is orders of magnitude faster than DFT and can, in principle, be coupled with any algorithm for structure prediction. Machine-learning models therefore seem promising to enable large-scale structure searches in the future. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Amorphous Alloy Membranes for High Temperature Hydrogen Separation

    Energy Technology Data Exchange (ETDEWEB)

    Coulter, K. [Southwest Research Inst. (SwRI), San Antonio, TX (United States)

    2013-09-30

    At the beginning of this project, thin film amorphous alloy membranes were considered a nascent but promising new technology for industrial-scale hydrogen gas separations from coal- derived syngas. This project used a combination of theoretical modeling, advanced physical vapor deposition fabricating, and laboratory and gasifier testing to develop amorphous alloy membranes that had the potential to meet Department of Energy (DOE) targets in the testing strategies outlined in the NETL Membrane Test Protocol. The project is complete with Southwest Research Institute® (SwRI®), Georgia Institute of Technology (GT), and Western Research Institute (WRI) having all operated independently and concurrently. GT studied the hydrogen transport properties of several amorphous alloys and found that ZrCu and ZrCuTi were the most promising candidates. GT also evaluated the hydrogen transport properties of V, Nb and Ta membranes coated with different transition-metal carbides (TMCs) (TM = Ti, Hf, Zr) catalytic layers by employing first-principles calculations together with statistical mechanics methods and determined that TiC was the most promising material to provide catalytic hydrogen dissociation. SwRI developed magnetron coating techniques to deposit a range of amorphous alloys onto both porous discs and tubular substrates. Unfortunately none of the amorphous alloys could be deposited without pinhole defects that undermined the selectivity of the membranes. WRI tested the thermal properties of the ZrCu and ZrNi alloys and found that under reducing environments the upper temperature limit of operation without recrystallization is ~250 °C. There were four publications generated from this project with two additional manuscripts in progress and six presentations were made at national and international technical conferences. The combination of the pinhole defects and the lack of high temperature stability make the theoretically identified most promising candidate amorphous alloys

  16. Molecular simulation of freestanding amorphous nickel thin films

    Energy Technology Data Exchange (ETDEWEB)

    Dong, T.Q. [Université Paris-Est, Laboratoire Modélisation et Simulation Multi Echelle, UMR 8208 CNRS, 5 Boulevard Descartes, 77454 Marne-la-Vallée, Cedex 2 (France); Hoang, V.V., E-mail: vvhoang2002@yahoo.com [Department of Physics, Institute of Technology, National University of Ho Chi Minh City, 268 Ly Thuong Kiet Street, District 10, Ho Chi Minh City (Viet Nam); Lauriat, G. [Université Paris-Est, Laboratoire Modélisation et Simulation Multi Echelle, UMR 8208 CNRS, 5 Boulevard Descartes, 77454 Marne-la-Vallée, Cedex 2 (France)

    2013-10-31

    Size effects on glass formation in freestanding Ni thin films have been studied via molecular dynamics simulation with the n-body Gupta interatomic potential. Atomic mechanism of glass formation in the films is determined via analysis of the spatio-temporal arrangements of solid-like atoms occurred upon cooling from the melt. Solid-like atoms are detected via the Lindemann ratio. We find that solid-like atoms initiate and grow mainly in the interior of the film and grow outward. Their number increases with decreasing temperature and at a glass transition temperature they dominate in the system to form a relatively rigid glassy state of a thin film shape. We find the existence of a mobile surface layer in both liquid and glassy states which can play an important role in various surface properties of amorphous Ni thin films. We find that glass formation is size independent for models containing 4000 to 108,000 atoms. Moreover, structure of amorphous Ni thin films has been studied in details via coordination number, Honeycutt–Andersen analysis, and density profile which reveal that amorphous thin films exhibit two different parts: interior and surface layer. The former exhibits almost the same structure like that found for the bulk while the latter behaves a more porous structure containing a large amount of undercoordinated sites which are the origin of various surface behaviors of the amorphous Ni or Ni-based thin films found in practice. - Highlights: • Glass formation is analyzed via spatio-temporal arrangements of solid-like atoms. • Amorphous Ni thin film exhibits two different parts: surface and interior. • Mobile surface layer enhances various surface properties of the amorphous Ni thin films. • Undercoordinated sites play an important role in various surface activities.

  17. Foot model for tracking temperature of safety boot insoles: application to different insole materials in firefighter boots.

    Science.gov (United States)

    García-Hernández, César; Sánchez-Álvarez, Eduardo J; Huertas-Talón, José-Luis

    2016-01-01

    This research is based on the development of a human foot model to study the temperature conditions of a foot bottom surface under extreme external conditions. This foot model is made by combining different manufacturing techniques to enable the simulation of bones and tissues, allowing the placement of sensors on its surface to track the temperature values of different points inside a shoe. These sensors let researchers capture valuable data during a defined period of time, making it possible to compare the features of different safety boots, socks or soles, among others. In this case, it has been applied to compare different plantar insole materials, placed into safety boots on a high-temperature surface.

  18. Timber tracking

    DEFF Research Database (Denmark)

    Düdder, Boris; Ross, Omry

    2017-01-01

    Managing and verifying forest products in a value chain is often reliant on easily manipulated document or digital tracking methods - Chain of Custody Systems. We aim to create a new means of tracking timber by developing a tamper proof digital system based on Blockchain technology. Blockchain...

  19. Hydrogen in disordered and amorphous solids

    International Nuclear Information System (INIS)

    Bambakidis, G; Bowman, R.C.

    1986-01-01

    This book presents information on the following topoics: elements of the theory of amorphous semiconductors; electronic structure of alpha-SiH; fluctuation induced gap states in amorphous hydrogenated silicon; hydrogen on semiconductor surfaces; the influence of hydrogen on the defects and instabilities in hydrogenated amorphous silicon; deuteron magnetic resonance in some amorphous semiconductors; formation of amorphous metals by solid state reactions of hydrogen with an intermetallic compound; NMR studies of the hydrides of disordered and amorphous alloys; neutron vibrational spectroscopy of disordered metal-hydrogen system; dynamical disorder of hydrogen in LaNi /SUB 5-y/ M /SUB y/ hydrides studied by quasi-elastic neutron scattering; recent studies of intermetallic hydrides; tritium in Pd and Pd /SUB 0.80/ Sg /SUB 0.20/ ; and determination of hydrogen concentration in thin films of absorbing materials

  20. The physics and applications of amorphous semiconductors

    CERN Document Server

    Madan, Arun

    1988-01-01

    This comprehensive, detailed treatise on the physics and applications of the new emerging technology of amorphous semiconductors focuses on specific device research problems such as the optimization of device performance. The first part of the book presents hydrogenated amorphous silicon type alloys, whose applications include inexpensive solar cells, thin film transistors, image scanners, electrophotography, optical recording and gas sensors. The second part of the book discusses amorphous chalcogenides, whose applications include electrophotography, switching, and memory elements. This boo

  1. Polyamorphous transition in amorphous fullerites C70

    International Nuclear Information System (INIS)

    Borisova, P. A.; Agafonov, S. S.; Glazkov, V. P.; D’yakonova, N. P.; Somenkov, V. A.

    2011-01-01

    Samples of amorphous fullerites C 70 have been obtained by mechanical activation (grinding in a ball mill). The structure of the samples has been investigated by neutron and X-ray diffraction. The high-temperature (up to 1200°C) annealing of amorphous fullerites revealed a polyamorphous transition from molecular to atomic glass, which is accompanied by the disappearance of fullerene halos at small scattering angles. Possible structural versions of the high-temperature amorphous phase are discussed.

  2. Evaluation of Empirical Tropospheric Models Using Satellite-Tracking Tropospheric Wet Delays with Water Vapor Radiometer at Tongji, China

    Directory of Open Access Journals (Sweden)

    Miaomiao Wang

    2016-02-01

    Full Text Available An empirical tropospheric delay model, together with a mapping function, is commonly used to correct the tropospheric errors in global navigation satellite system (GNSS processing. As is well-known, the accuracy of tropospheric delay models relies mainly on the correction efficiency for tropospheric wet delays. In this paper, we evaluate the accuracy of three tropospheric delay models, together with five mapping functions in wet delays calculation. The evaluations are conducted by comparing their slant wet delays with those measured by water vapor radiometer based on its satellite-tracking function (collected data with large liquid water path is removed. For all 15 combinations of three tropospheric models and five mapping functions, their accuracies as a function of elevation are statistically analyzed by using nine-day data in two scenarios, with and without meteorological data. The results show that (1 no matter with or without meteorological data, there is no practical difference between mapping functions, i.e., Chao, Ifadis, Vienna Mapping Function 1 (VMF1, Niell Mapping Function (NMF, and MTT Mapping Function (MTT; (2 without meteorological data, the UNB3 is much better than Saastamoinen and Hopfield models, while the Saastamoinen model performed slightly better than the Hopfield model; (3 with meteorological data, the accuracies of all three tropospheric delay models are improved to be comparable, especially for lower elevations. In addition, the kinematic precise point positioning where no parameter is set up for tropospheric delay modification is conducted to further evaluate the performance of tropospheric delay models in positioning accuracy. It is shown that the UNB3 model is best and can achieve about 10 cm accuracy for the N and E coordinate component while 20 cm accuracy for the U coordinate component no matter the meteorological data is available or not. This accuracy can be obtained by the Saastamoinen model only when

  3. Amorphous layer depth dependence on implant parameters during Si self-implantation

    International Nuclear Information System (INIS)

    Lopez, Pedro; Pelaz, Lourdes; Marques, Luis A.; Barbolla, Juan; Gossmann, H.-J.L.; Agarwal, Aditya; Kimura, Kenji; Matsushita, Tomoyoshi

    2005-01-01

    Preamorphization followed by low temperature solid phase epitaxial regrowth has been proved to provide a high activation of the dopants with minimal diffusion. However, the end of range damage present after regrowth beyond the initial amorphous/crystalline interface causes diffusion and deactivation of dopants during subsequent annealing. In this paper, we study the influence of implant conditions on the depth of the amorphous layer during Si self-implantation. We compare experimental data with our simulation results obtained using an atomistic amorphization-recrystallization model recently developed. We show that the amorphous/crystalline interface depth initially increases with dose but saturates at high doses. Beam current and wafer temperature also alter the depth of the amorphous layer and the amount of residual damage by affecting the dynamic annealing of the damage. These parameters are not always well controlled or specified in experiments and can explain differences observed in dopant profiles

  4. The effect of surfactants on the dissolution behavior of amorphous formulations

    DEFF Research Database (Denmark)

    Mah, Pei T; Peltonen, Leena; Novakovic, Dunja

    2016-01-01

    The optimal design of oral amorphous formulations benefits from the use of excipients to maintain drug supersaturation and thus ensures adequate absorption during intestinal transit. The use of surfactants for the maintenance of supersaturation in amorphous formulations has not been investigated...... in detail. The main aim of this study was to investigate the effect of surfactant on the dissolution behavior of neat amorphous drug and binary polymer based solid dispersion. Indomethacin was used as the model drug and the surfactants studied were polysorbate 80 and poloxamer 407. The presence...... of surfactants (alone or in combination with polymers) in the buffer was detrimental to the dissolution of neat amorphous indomethacin, suggesting that the surfactants promoted the crystallization of neat amorphous indomethacin. In contrast, the presence of surfactants (0.01% w/v) in the buffer resulted...

  5. Amorphous silicon based radiation detectors

    International Nuclear Information System (INIS)

    Perez-Mendez, V.; Cho, G.; Drewery, J.; Jing, T.; Kaplan, S.N.; Qureshi, S.; Wildermuth, D.; Fujieda, I.; Street, R.A.

    1991-07-01

    We describe the characteristics of thin(1 μm) and thick (>30μm) hydrogenated amorphous silicon p-i-n diodes which are optimized for detecting and recording the spatial distribution of charged particles, x-rays and γ rays. For x-ray, γ ray, and charged particle detection we can use thin p-i-n photosensitive diode arrays coupled to evaporated layers of suitable scintillators. For direct detection of charged particles with high resistance to radiation damage, we use the thick p-i-n diode arrays. 13 refs., 7 figs

  6. Ion-induced damage and amorphization in Si

    International Nuclear Information System (INIS)

    Holland, O.W.; White, C.W.

    1990-01-01

    Ion-induced damage growth in high-energy, self-ion irradiated Si was studied using electron microscopy and Rutherford backscattering spectroscopy. The results show that there is a marked variation in the rate of damage growth, as well as the damage morphology, along the path of the ion. Near the ion end-of-range (eor), damage increases monotonically with ion fluence until a buried amorphous layer is formed, while damage growth saturates at a low level in the region ahead. The morphology of the damage in the saturated region is shown to consist predominantly of simple defect clusters such as the divacancy. Damage growth remains saturated ahead of the eor until expansion of the buried amorphous layer encroaches into the region. A homogeneous growth model is presented which accounts for damage saturation, and accurately predicts the dose-rate dependence of the saturation level. Modifications of the model are discussed which are needed to account for the rapid growth in the eor region and near the interface of the buried amorphous layer. Two important factors contributing to rapid damage growth are identified. Spatial separation of the Frenkel defect pairs (i.e. interstitials and vacancies) due to the momentum of the interstitials is shown to greatly impact damage growth near the eor, while uniaxial strain in the interfacial region of the amorphous layer is identified as an important factor contributing to growth at that location. 20 refs., 10 figs

  7. Mathematical Modeling Of The Acceleration Process In Race-track Microtron

    CERN Document Server

    Gromov, A M; Vasilev, A A

    2004-01-01

    The precise calculations of beam dynamics are needed to make choice of optimal design parameters of race-track microtron. As a result, the necessary physical require-ments to the accelerator systems become found. For cal-culation of the magnetic field, POISSON LANL code is used. Acceleration of the beam is investigated with the help of the program of MathCad. Nonlinear distribution of the field in magnets of micro-tron with adjustable reverse field was simulated. The equation of motion of a beam in bending magnets of re-circulation system are found and solved by a numerical method. Trajectories of the beam for all orbits in a micro-tron are received. The recursive equation for calculation of the largest area of injected beam phase and power spreads providing steady acceleration process is written. The acceleration of the beam with maximal phase-energy area through all orbits of microtron was simulated. The velocity of accelerated particles on first orbits dif-fers from velocity of light. The minimal energy ...

  8. MODEL PREDICTIVE CONTROL FOR PHOTOVOLTAIC STATION MAXIMUM POWER POINT TRACKING SYSTEM

    Directory of Open Access Journals (Sweden)

    I. Elzein

    2015-01-01

    Full Text Available The purpose of this paper is to present an alternative maximum power point tracking, MPPT, algorithm for a photovoltaic module, PVM, to produce the maximum power, Pmax, using the optimal duty ratio, D, for different types of converters and load matching.We present a state-based approach to the design of the maximum power point tracker for a stand-alone photovoltaic power generation system. The system under consideration consists of a solar array with nonlinear time-varying characteristics, a step-up converter with appropriate filter.The proposed algorithm has the advantages of maximizing the efficiency of the power utilization, can be integrated to other MPPT algorithms without affecting the PVM performance, is excellent for Real-Time applications and is a robust analytical method, different from the traditional MPPT algorithms which are more based on trial and error, or comparisons between present and past states. The procedure to calculate the optimal duty ratio for a buck, boost and buck-boost converters, to transfer the maximum power from a PVM to a load, is presented in the paper. Additionally, the existence and uniqueness of optimal internal impedance, to transfer the maximum power from a photovoltaic module using load matching, is proved.

  9. Variation that can be expected when using particle tracking models in connectivity studies

    DEFF Research Database (Denmark)

    Hufnagl, Marc; Payne, Mark; Lacroix, Geneviève

    2017-01-01

    •A suite of ocean circulation and Lagrangian models were compared to determine inter-model uncertainty and variation.•Absolute results (positions, temperatures, etc.) varied between models, but trends were comparable.•More plaice than sole larvae reached a marine protected area although released...

  10. Relationships of radiation track structure to biological effect: a re-interpretation of the parameters of the Katz model

    International Nuclear Information System (INIS)

    Goodhead, D.T.

    1989-01-01

    The Katz track-model of cell inactivation has been more successful than any other biophysical model in fitting and predicting inactivation of mammalian cells exposed to a wide variety of ionising radiations. Although the model was developed as a parameterised phenomenological description, without necessarily implying any particular mechanistic processes, the present analysis attempts to interpret it and thereby benefit further from its success to date. A literal interpretation of the parameters leads to contradictions with other experimental and theoretical information, especially since the fitted parameters imply very large (> ∼ 4 μm) subcellular sensitive sites which each require very large amounts (> ∼ 100 keV) of energy deposition in order to be inactivated. Comparisons of these fits with those for cell mutation suggest a re-interpretation in terms of (1) very much smaller sites and (2) a clearer distinction between the ion-kill and γ-kill modes of inactivation. It is suggested that this re-interpretation may be able to guide future development of the phenomenological Katz model and also parameterisation of mechanistic biophysical models. (author)

  11. Nanostructural characterization of amorphous diamondlike carbon films

    Energy Technology Data Exchange (ETDEWEB)

    SIEGAL,MICHAEL P.; TALLANT,DAVID R.; MARTINEZ-MIRANDA,L.J.; BARBOUR,J. CHARLES; SIMPSON,REGINA L.; OVERMYER,DONALD L.

    2000-01-27

    Nanostructural characterization of amorphous diamondlike carbon (a-C) films grown on silicon using pulsed-laser deposition (PLD) is correlated to both growth energetic and film thickness. Raman spectroscopy and x-ray reflectivity probe both the topological nature of 3- and 4-fold coordinated carbon atom bonding and the topographical clustering of their distributions within a given film. In general, increasing the energetic of PLD growth results in films becoming more ``diamondlike'', i.e. increasing mass density and decreasing optical absorbance. However, these same properties decrease appreciably with thickness. The topology of carbon atom bonding is different for material near the substrate interface compared to material within the bulk portion of an a-C film. A simple model balancing the energy of residual stress and the free energies of resulting carbon topologies is proposed to provide an explanation of the evolution of topographical bonding clusters in a growing a-C film.

  12. Prediction of heating rate controlled viscous flow activation energy during spark plasma sintering of amorphous alloy powders

    Science.gov (United States)

    Paul, Tanaji; Harimkar, Sandip P.

    2017-07-01

    The viscous flow behavior of Fe-based amorphous alloy powder during isochronal spark plasma sintering was analyzed under the integrated theoretical background of the Arrhenius and directional structural relaxation models. A relationship between viscous flow activation energy and heating rate was derived. An extension of the pertinent analysis to Ti-based amorphous alloys confirmed the broad applicability of such a relationship for predicting the activation energy for sintering below the glass transition temperature (T g) of the amorphous alloy powders.

  13. Studies of hydrogenated amorphous silicon

    Energy Technology Data Exchange (ETDEWEB)

    Bishop, S G; Carlos, W E

    1984-07-01

    This report discusses the results of probing the defect structure and bonding of hydrogenated amorphous silicon films using both nuclear magnetic resonance (NMR) and electron spin resonance (ESR). The doping efficiency of boron in a-Si:H was found to be less than 1%, with 90% of the boron in a threefold coordinated state. On the other hand, phosphorus NMR chemical shift measurements yielded a ration of threefold to fourfold P sites of roughly 4 to 1. Various resonance lines were observed in heavily boron- and phosphorus-doped films and a-SiC:H alloys. These lines were attributed to band tail states on twofold coordinated silicon. In a-SiC:H films, a strong resonance was attributed to dangling bonds on carbon atoms. ESR measurements on low-pressure chemical-vapor-deposited (LPCVD) a-Si:H were performed on samples. The defect density in the bulk of the films was 10/sup 17//cc with a factor of 3 increase at the surface of the sample. The ESR spectrum of LPCVD-prepared films was not affected by prolonged exposure to strong light. Microcrystalline silicon samples were also examined. The phosphorus-doped films showed a strong signal from the crystalline material and no resonance from the amorphous matrix. This shows that phosphorus is incorporated in the crystals and is active as a dopant. No signal was recorded from the boron-doped films.

  14. Heavy Ion Track Temperature with the High Level of Specific Inelastic Energy Loss in Materials at the Thermal Spike Model

    CERN Document Server

    Didyk, A Yu; Semina, V K

    2003-01-01

    The thermal spike model in materials under the irradiation by swift heavy ions with high specific energy loss is considered taking into account the temperature dependence along the ion trajectrory. The numerical solutions of the temperature system equations for the temperatures of lattice and electrons are obtained, takinig into account the possible heating of lattice up to the melting and evaporation points, i.e., with the two phase transitions are obtained. The pressure in the volume of heavy ion track and their influence on the changes of thermodynamical parameters are introduced. The influence of defects on the "hot" electron free path is discussed. The numerical analysis of the lattice temperature at low and high temperatures of the thermal conductivity and heat capacity parameter values was carried out.

  15. Fluidity evaluation of cell membrane model formed on graphene oxide with single particle tracking using quantum dot

    Science.gov (United States)

    Okamoto, Yoshiaki; Motegi, Toshinori; Iwasa, Seiji; Sandhu, Adarsh; Tero, Ryugo

    2015-04-01

    The lipid bilayer is the fundamental structure of plasma membranes, and artificial lipid bilayer membranes are used as model systems of cell membranes. Recently we reported the formation of a supported lipid bilayer (SLB) on graphene oxide (GO) by the vesicle fusion method. In this study, we conjugated a quantum dot (Qdot) on the SLB surface as a fluorescence probe brighter than dye-labeled lipid molecules, to qualitatively evaluate the fluidity of the SLB on GO by the single particle tracking method. We obtained the diffusion coefficient of the Qdot-conjugated lipids in the SLB on GO. We also performed the Qdot conjugation on the SLB containing a lipid conjugated with polyethylene glycol, to prevent the nonspecific adsorption of Qdots. The difference in the diffusion coefficients between the SLBs on the GO and the bare SiO2 regions was evaluated from the trajectory of single Qdot-conjugated lipid diffusing between the two regions.

  16. Heavy ion track temperature with the high level of specific inelastic energy loss in materials at the thermal spike model

    International Nuclear Information System (INIS)

    Didyk, A.Yu.; Robuk, V.N.; Semina, V.K.

    2003-01-01

    The thermal spike model in materials under the irradiation by swift heavy ions with high specific energy loss is considered taking into account the temperature dependence along the ion trajectory. The numerical solutions of the temperature system equations for the temperatures of lattice up to the melting and evaporation points, i.e., with the two phase transitions are obtained. The pressure in the volume of heavy ion track and its influence on the changes of thermodynamical parameters are introduced. The influence of defects on the 'hot' electron free path is discussed. The numerical analysis of the lattice temperature at low and high temperatures of the thermal conductivity and heat capacity parameter values was carried out. (author)

  17. Teaching and implementing autonomous robotic lab walkthroughs in a biotech laboratory through model-based visual tracking

    Science.gov (United States)

    Wojtczyk, Martin; Panin, Giorgio; Röder, Thorsten; Lenz, Claus; Nair, Suraj; Heidemann, Rüdiger; Goudar, Chetan; Knoll, Alois

    2010-01-01

    After utilizing robots for more than 30 years for classic industrial automation applications, service robots form a constantly increasing market, although the big breakthrough is still awaited. Our approach to service robots was driven by the idea of supporting lab personnel in a biotechnology laboratory. After initial development in Germany, a mobile robot platform extended with an industrial manipulator and the necessary sensors for indoor localization and object manipulation, has been shipped to Bayer HealthCare in Berkeley, CA, USA, a global player in the sector of biopharmaceutical products, located in the San Francisco bay area. The determined goal of the mobile manipulator is to support the off-shift staff to carry out completely autonomous or guided, remote controlled lab walkthroughs, which we implement utilizing a recent development of our computer vision group: OpenTL - an integrated framework for model-based visual tracking.

  18. Are we there yet? Tracking the development of new model systems.

    Science.gov (United States)

    Abzhanov, Arhat; Extavour, Cassandra G; Groover, Andrew; Hodges, Scott A; Hoekstra, Hopi E; Kramer, Elena M; Monteiro, Antonia

    2008-07-01

    It is increasingly clear that additional 'model' systems are needed to elucidate the genetic and developmental basis of organismal diversity. Whereas model system development previously required enormous investment, recent advances including the decreasing cost of DNA sequencing and the power of reverse genetics to study gene function are greatly facilitating the process. In this review, we consider two aspects of the development of new genetic model systems: first, the types of questions being advanced using these new models; and second, the essential characteristics and molecular tools for new models, depending on the research focus. We hope that researchers will be inspired to explore this array of emerging models and even consider developing new molecular tools for their own favorite organism.

  19. Correlation peak analysis applied to a sequence of images using two different filters for eye tracking model

    Science.gov (United States)

    Patrón, Verónica A.; Álvarez Borrego, Josué; Coronel Beltrán, Ángel

    2015-09-01

    Eye tracking has many useful applications that range from biometrics to face recognition and human-computer interaction. The analysis of the characteristics of the eyes has become one of the methods to accomplish the location of the eyes and the tracking of the point of gaze. Characteristics such as the contrast between the iris and the sclera, the shape, and distribution of colors and dark/light zones in the area are the starting point for these analyses. In this work, the focus will be on the contrast between the iris and the sclera, performing a correlation in the frequency domain. The images are acquired with an ordinary camera, which with were taken images of thirty-one volunteers. The reference image is an image of the subjects looking to a point in front of them at 0° angle. Then sequences of images are taken with the subject looking at different angles. These images are processed in MATLAB, obtaining the maximum correlation peak for each image, using two different filters. Each filter were analyzed and then one was selected, which is the filter that gives the best performance in terms of the utility of the data, which is displayed in graphs that shows the decay of the correlation peak as the eye moves progressively at different angle. This data will be used to obtain a mathematical model or function that establishes a relationship between the angle of vision (AOV) and the maximum correlation peak (MCP). This model will be tested using different input images from other subject not contained in the initial database, being able to predict angle of vision using the maximum correlation peak data.

  20. Non-invasive stem cell tracking in hindlimb ischemia animal model using bio-orthogonal copper-free click chemistry.

    Science.gov (United States)

    Lee, Si Yeon; Lee, Sangmin; Lee, Jangwook; Yhee, Ji Young; Yoon, Hwa In; Park, Soon-Jung; Koo, Heebeom; Moon, Sung-Hwan; Lee, Hyukjin; Cho, Yong Woo; Kang, Sun Woong; Lee, Sang-Yup; Kim, Kwangmeyung

    2016-10-28

    Labeling of stem cells aims to distinguish transplanted cells from host cells, understand in vivo fate of transplanted cells, particularly important in stem cell therapy. Adipose-derived mesenchymal stem cells (ASCs) are considered as an emerging therapeutic option for tissue regeneration, but much remains to be understood regarding the in vivo evidence. In this study, a simple and efficient cell labeling method for labeling and tracking of stem cells was developed based on bio-orthogonal copper-free click chemistry, and it was applied in a mouse hindlimb ischemia model. The human ASCs were treated with tetra-acetylated N-azidoacetyl-d-mannosamine (Ac 4 ManNAz) to generate glycoprotein with unnatural azide groups on the cell surface, and the generated azide groups were fluorescently labeled by specific binding of dibenzylcyclooctyne-conjugated Cy5 (DBCO-Cy5). The safe and long-term labeling of the hASCs by this method was first investigated in vitro. Then the DBCO-Cy5-hASCs were transplanted into the hindlimb ischemia mice model, and we could monitor and track in vivo fate of the cells using optical imaging system. We could clearly observe the migration potent of the hASCs toward the ischemic lesion. This approach to design and tailor new method for labeling of stem cells may be useful to provide better understanding on the therapeutic effects of transplanted stem cells into the target diseases. Copyright © 2016 Elsevier Inc. All rights reserved.

  1. Forward and Inverse Predictive Model for the Trajectory Tracking Control of a Lower Limb Exoskeleton for Gait Rehabilitation: Simulation modelling analysis

    Science.gov (United States)

    Zakaria, M. A.; Majeed, A. P. P. A.; Taha, Z.; Alim, M. M.; Baarath, K.

    2018-03-01

    The movement of a lower limb exoskeleton requires a reasonably accurate control method to allow for an effective gait therapy session to transpire. Trajectory tracking is a nontrivial means of passive rehabilitation technique to correct the motion of the patients’ impaired limb. This paper proposes an inverse predictive model that is coupled together with the forward kinematics of the exoskeleton to estimate the behaviour of the system. A conventional PID control system is used to converge the required joint angles based on the desired input from the inverse predictive model. It was demonstrated through the present study, that the inverse predictive model is capable of meeting the trajectory demand with acceptable error tolerance. The findings further suggest the ability of the predictive model of the exoskeleton to predict a correct joint angle command to the system.

  2. Modelling untrackable orbital debris associated with a tracked space debris cloud.

    Science.gov (United States)

    Culp, R. D.; Madler, R. A.

    A computer model, including both the trackable and untrackable size regimes, has been developed to simulate several types of satellite fragmentations. These particle swarms are then propagated using a perturbation model to predict the collision hazard associated with the entire swarm. The results of this study will aid in estimating the long term hazard posed by debris particles to operating satellites and space operations.

  3. How High Is the Tramping Track? Mathematising and Applying in a Calculus Model-Eliciting Activity

    Science.gov (United States)

    Yoon, Caroline; Dreyfus, Tommy; Thomas, Michael O. J.

    2010-01-01

    Two complementary processes involved in mathematical modelling are mathematising a realistic situation and applying a mathematical technique to a given realistic situation. We present and analyse work from two undergraduate students and two secondary school teachers who engaged in both processes during a mathematical modelling task that required…

  4. Model cortical responses for the detection of perceptual onsets and beat tracking in singing

    NARCIS (Netherlands)

    Coath, M.; Denham, S.L.; Smith, L.M.; Honing, H.; Hazan, A.; Holonowicz, P.; Purwins, H.

    2009-01-01

    We describe a biophysically motivated model of auditory salience based on a model of cortical responses and present results that show that the derived measure of salience can be used to identify the position of perceptual onsets in a musical stimulus successfully. The salience measure is also shown

  5. Development of Mathematical Models for Investigating Maximal Power Point Tracking Algorithms

    Directory of Open Access Journals (Sweden)

    Dominykas Vasarevičius

    2012-04-01

    Full Text Available Solar cells generate maximum power only when the load is optimized according insolation and module temperature. This function is performed by MPPT systems. While developing MPPT, it is useful to create a mathematical model that allows the simulation of different weather conditions affecting solar modules. Solar insolation, cloud cover imitation and solar cell models have been created in Matlab/Simulink environment. Comparing the simulation of solar insolation on a cloudy day with the measurements made using a pyrometer show that the model generates signal changes according to the laws similar to those of a real life signal. The model can generate solar insolation values in real time, which is useful for predicting the amount of electrical energy produced from solar power. The model can operate with the help of using the stored signal, thus a comparison of different MPPT algorithms can be provided.Article in Lithuanian

  6. Charge transport in amorphous organic semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Lukyanov, Alexander

    2011-03-15

    Organic semiconductors with the unique combination of electronic and mechanical properties may offer cost-effective ways of realizing many electronic applications, e. g. large-area flexible displays, printed integrated circuits and plastic solar cells. In order to facilitate the rational compound design of organic semiconductors, it is essential to understand relevant physical properties e. g. charge transport. This, however, is not straightforward, since physical models operating on different time and length scales need to be combined. First, the material morphology has to be known at an atomistic scale. For this atomistic molecular dynamics simulations can be employed, provided that an atomistic force field is available. Otherwise it has to be developed based on the existing force fields and first principle calculations. However, atomistic simulations are typically limited to the nanometer length- and nanosecond time-scales. To overcome these limitations, systematic coarse-graining techniques can be used. In the first part of this thesis, it is demonstrated how a force field can be parameterized for a typical organic molecule. Then different coarse-graining approaches are introduced together with the analysis of their advantages and problems. When atomistic morphology is available, charge transport can be studied by combining the high-temperature Marcus theory with kinetic Monte Carlo simulations. The approach is applied to the hole transport in amorphous films of tris(8- hydroxyquinoline)aluminium (Alq{sub 3}). First the influence of the force field parameters and the corresponding morphological changes on charge transport is studied. It is shown that the energetic disorder plays an important role for amorphous Alq{sub 3}, defining charge carrier dynamics. Its spatial correlations govern the Poole-Frenkel behavior of the charge carrier mobility. It is found that hole transport is dispersive for system sizes accessible to simulations, meaning that calculated

  7. Amorphous molybdenum sulfides as hydrogen evolution catalysts.

    Science.gov (United States)

    Morales-Guio, Carlos G; Hu, Xile

    2014-08-19

    from simple wet-chemical routes. Electron transport is sometimes slow in the particle catalysts, and an impedance model has been established to identify this slow electron transport. Finally, the amorphous molybdenum sulfide film catalyst has been integrated onto a copper(I) oxide photocathode for photoelectrochemical hydrogen evolution. The conformal catalyst efficiently extracts the excited electrons to give an impressive photocurrent density of -5.7 mA/cm(2) at 0 V vs RHE. The catalyst also confers good stability.

  8. Mechanisms of amorphization-induced swelling in silicon carbide: the molecular dynamics answer

    International Nuclear Information System (INIS)

    Bertolus, M.; Ribeiro, F.; Defranceschi, M.

    2007-01-01

    We present here the continuation of an investigation of the irradiation-induced swelling of SiC using classical molecular dynamics (CMD) simulations. Heavy ion irradiation has been assumed to affect the material in two successive steps (a) creation of local atomic disorder, modeled by the introduction of extended amorphous areas with various sizes and shapes in a crystalline SiC sample at constant volume (b) induced swelling, determined through relaxation using Molecular Dynamics at constant pressure. This swelling has been computed as a function of the amorphous fraction introduced. Two different definitions of the amorphous fraction were introduced to enable meaningful comparisons of our calculations with experiments and elastic modeling. One definition based on the displacements relative to the ideal lattice positions was used to compare the CMD results with data from experiments combining ion implantations and channeled Rutherford Backscattering analyses. A second definition based on atomic coordination was used to compare the CMD results to those yielded by a simplified elastic model. The results obtained are as follows. On the one hand, comparison of the swelling obtained as a function of the lattice amorphous fraction with the experimental results shows that the melting-quench amorphization simulates the best the irradiation-induced amorphization observed experimentally. This is consistent with the thermal spike phenomenon taking place during ion implantation. On the other hand, disorder analysis at the atomic scale confirms the elastic behavior of the amorphization-induced swelling, in agreement with the comparison with the results of an elastic model. First, no major structural reconstruction occurs during relaxation or annealing. Second, the systems with the most disordered and constrained amorphous area undergo the largest swelling. This means that the disorder and the constraints of the bulk amorphous area are the driving forces for the swelling

  9. Statistical properties of Barkhausen noise in amorphous ferromagnetic films.

    Science.gov (United States)

    Bohn, F; Corrêa, M A; Carara, M; Papanikolaou, S; Durin, G; Sommer, R L

    2014-09-01

    We investigate the statistical properties of the Barkhausen noise in amorphous ferromagnetic films with thicknesses in the range between 100 and 1000 nm. From Barkhausen noise time series measured with the traditional inductive technique, we perform a wide statistical analysis and establish the scaling exponents τ,α,1/σνz, and ϑ. We also focus on the average shape of the avalanches, which gives further indications on the domain-wall dynamics. Based on experimental results, we group the amorphous films in a single universality class, characterized by scaling exponents τ=1.28±0.02,α=1.52±0.3, and 1/σνz=ϑ=1.83±0.03, values compatible with that obtained for several bulk amorphous magnetic materials. Besides, we verify that the avalanche shape depends on the universality class. By considering the theoretical models for the dynamics of a ferromagnetic domain wall driven by an external magnetic field through a disordered medium found in literature, we interpret the results and identify an experimental evidence that these amorphous films, within this thickness range, present a typical three-dimensional magnetic behavior with predominant short-range elastic interactions governing the domain-wall dynamics. Moreover, we provide experimental support for the validity of a general scaling form for the average avalanche shape for non-mean-field systems.

  10. Structural morphology of amorphous conducting carbon film

    Indian Academy of Sciences (India)

    Unknown

    in nanotubes and sp3 rich amorphous carbons for their application in field emission, device application, etc in- vestigations on sp2 rich amorphous carbon forms are very few. Though DLC films have potential application in field emission (FE) due to their low threshold voltage, the carbon centres, which are believed to play ...

  11. Towards upconversion for amorphous silicon solar cells

    NARCIS (Netherlands)

    de Wild, J.; Meijerink, A.; Rath, J.K.; van Sark, W.G.J.H.M.; Schropp, R.E.I.

    2010-01-01

    Upconversion of subbandgap light of thin film single junction amorphous silicon solar cells may enhance their performance in the near infrared (NIR). In this paper we report on the application of the NIR–vis upconverter β-NaYF4:Yb3+(18%) Er3+(2%) at the back of an amorphous silicon solar cell in

  12. Film adhesion in amorphous silicon solar cells

    Indian Academy of Sciences (India)

    TECS

    flexible triple junction, amorphous silicon solar cells. At the Malaysia Energy Centre (MEC), we fabricated triple junction amorphous silicon solar cells (up to 12⋅7% efficiency (Wang et al 2002)) and laser-interconnected modules on steel, glass and polyimide substrates. A major issue encountered is the adhesion of thin film ...

  13. Colors and the evolution of amorphous galaxies

    International Nuclear Information System (INIS)

    Gallagher, J.S. III; Hunter, D.A.

    1987-01-01

    UBVRI and H-alpha photometric observations are presented for 16 amorphous galaxies and a comparison sample of Magellanic irregular (Im) and Sc spiral galaxies. These data are analyzed in terms of star-formation rates and histories in amorphous galaxies. Amorphous galaxies have mean global colors and star-formation rates per unit area that are similar to those in giant Im systems, despite differences in spatial distributions of star-forming centers in these two galactic structural classes. Amorphous galaxies differ from giant Im systems in having somewhat wider scatter in relationships between B - V and U - B colors, and between U - B and L(H-alpha)/L(B). This scatter is interpreted as resulting from rapid variations in star-formation rates during the recent past, which could be a natural consequence of the concentration of star-forming activity into centrally located, supergiant young stellar complexes in many amorphous galaxies. While the unusual spatial distribution and intensity of star formation in some amorphous galaxies is due to interactions with other galaxies, several amorphous galaxies are relatively isolated and thus the processes must be internal. The ultimate evolutionary fate of rapidly evolving amorphous galaxies remains unknown. 77 references

  14. Amorphization of ice under mechanical stresses

    Science.gov (United States)

    Bordonskii, G. S.; Krylov, S. D.

    2017-11-01

    The dielectric parameters of freshly produced freshwater ice in the microwave range are investigated. It is established that this kind of ice contains a noticeable amount of amorphous ice. Its production is associated with plastic deformation under mechanical stresses. An assessment of the dielectric-permeability change caused by amorphous ice in the state of a slowly flowing medium is given.

  15. Electron beam recrystallization of amorphous semiconductor materials

    Science.gov (United States)

    Evans, J. C., Jr.

    1968-01-01

    Nucleation and growth of crystalline films of silicon, germanium, and cadmium sulfide on substrates of plastic and glass were investigated. Amorphous films of germanium, silicon, and cadmium sulfide on amorphous substrates of glass and plastic were converted to the crystalline condition by electron bombardment.

  16. Photoexcitation-induced processes in amorphous semiconductors

    International Nuclear Information System (INIS)

    Singh, Jai

    2005-01-01

    Theories for the mechanism of photo-induced processes of photodarkening (PD), volume expansion (VE) in amorphous chalcogenides are presented. Rates of spontaneous emission of photons by radiative recombination of excitons in amorphous semiconductors are also calculated and applied to study the excitonic photoluminescence in a-Si:H. Results are compared with previous theories

  17. Using Modeling and Simulation to Evaluate Stability and Traction Performance of a Track Laying Robotic Vehicle

    National Research Council Canada - National Science Library

    Gunter, Dave D; Bylsma, Wesley W; Edgar, Kevin; Letherwood, Mike D; Gorsich, David J

    2005-01-01

    The objective of this paper will be to describe the computer-based modeling, simulation, and limited field testing effort that has been undertaken to investigate the dynamic performance of an unmanned...

  18. Collaboration and abstract representations: towards predictive models based on raw speech and eye-tracking data

    OpenAIRE

    Nüssli, Marc-Antoine; Jermann, Patrick; Sangin, Mirweis; Dillenbourg, Pierre

    2009-01-01

    This study aims to explore the possibility of using machine learning techniques to build predictive models of performance in collaborative induction tasks. More specifically, we explored how signal-level data, like eye-gaze data and raw speech may be used to build such models. The results show that such low level features have effectively some potential to predict performance in such tasks. Implications for future applications design are shortly discussed.

  19. SOLUTION OF MATHEMATICAL MODEL FOR TRACKED VEHICLE MOVEMENT UNDER DIFFERENT CONTROL ACTIONS

    Directory of Open Access Journals (Sweden)

    S. Volosnikov

    2017-06-01

    Full Text Available The paper presents a solution to the mathematical model of the caterpillar platform motion in the process of going into corner at various speed of movement. The presented model made it possible to obtain characteristic trajectories of a caterpillar platform in a turn for different road conditions and control actions. The «steering wheel» and «levers», which are most widely used in turn control systems, are considered as controls for the caterpillar platform.

  20. Improving co-amorphous drug formulations by the addition of the highly water soluble amino acid proline

    DEFF Research Database (Denmark)

    Jensen, Katrine Birgitte Tarp; Löbmann, Korbinian; Rades, Thomas

    2014-01-01

    the molecular interactions in the form of hydrogen bonds between all three components in the mixture. A salt formation between the acidic drug, NAP, and the basic amino acid, ARG, was found in co-amorphous NAP–ARG. In comparison to crystalline NAP, binary NAP–TRP and NAP–ARG, it could be shown that the highly......Co-amorphous drug amino acid mixtures were previously shown to be a promising approach to create physically stable amorphous systems with the improved dissolution properties of poorly water-soluble drugs. The aim of this work was to expand the co-amorphous drug amino acid mixture approach...... by combining the model drug, naproxen (NAP), with an amino acid to physically stabilize the co-amorphous system (tryptophan, TRP, or arginine, ARG) and a second highly soluble amino acid (proline, PRO) for an additional improvement of the dissolution rate. Co-amorphous drug-amino acid blends were prepared...