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1
Zheng, Guoliang, Lili Wan, Tiefeng He, Qingyang Wu e Xuhui Zhang. "The Propagation Characteristics of Circular Airy Beams with Propagational Fractional-Order Optical Vortices". Photonics 11, n. 1 (7 gennaio 2024): 64. http://dx.doi.org/10.3390/photonics11010064.
Testo completoAbstract (sommario):
We investigate the propagation properties of circular Airy beams (CABs) with propagational fractional-order optical vortices (OVs). The superposition of the phase singularity and polarization singularity from a vortex vector beam (VVB) plays a significant role in creating a propagational fractional vortex beam. Propagational fractional vortex beams can be considered as a superposition of left and right circularly polarized vortex beams with different integer topological charges (TCs). We study the propagation characteristics of two kinds of propagational fractional vortex CABs, and the results show that both of the two kinds of beams can stably propagate in free space, and they exhibit an “abruptly auto-focusing” property and “self-healing” property during the propagation. The intensity distribution of the first kind of propagational fractional vortex CAB has an odd number of petals (2m + 1), while the second kind of beam has a crescent-shaped intensity distribution. The influence of turbulence on the beam propagation through atmosphere under different turbulence strengths is also numerically studied in this paper. A fractional vortex CAB with an initial radius r0 = 10 mm can retain its shape after propagating 20 m when the atmospheric refractive-index structure constant CN2=0.2×10−12m−2/3. Our results are expected to broaden the application of CABs.
2
Abrame, Andre, e Djamal Habet. "Handling All Unit Propagation Reasons in Exact Max-SAT Solvers". Proceedings of the International Symposium on Combinatorial Search 5, n. 1 (1 settembre 2021): 2–9. http://dx.doi.org/10.1609/socs.v5i1.18313.
Testo completoAbstract (sommario):
Unit propagation (UP) based method are widely used in Branch and Bound (BnB) Max-SAT solvers for detecting disjoint inconsistent subsets (IS) during the lower bound (LB) estimation. UP consists in assigning to true (propagating) all the literals which appear in unit clauses. The existing implementations of UP only consider the first unit clause causing the assignment of each variable, thus the propagations must be done and undone chronologically to ensure that all the unit clauses are properly exploited. Max-SAT BnB solvers transforms the formulas to ensure IS disjointness. These transformations remove clauses from the formula thus propagations are frequently undone. Since the propagations are undone in chronological order, many useless unassignments and reassignments are performed. We propose in this paper a new unit propagation scheme which considers all the unit clauses causing the assignment of the variables by UP. This new scheme allows to undo propagations in a non-chronological way and thus it reduces the number of redundant propagation steps made by BnB solvers. We also show how the information available with this new scheme can be used to influence the characteristics of the IS built by BnB solvers. We propose a heuristic which aims at reducing their size, and thus improving the quality of the LB estimation. We have implemented the new propagation scheme as well as the IS building heuristic in our solver MSsolver. We present and discuss the results of the experimental study we have performed.
3
Wang, Bin, Guosen Chen e Fei Liu. "Diversity of the Madden-Julian Oscillation". Science Advances 5, n. 7 (luglio 2019): eaax0220. http://dx.doi.org/10.1126/sciadv.aax0220.
Testo completoAbstract (sommario):
Madden-Julian Oscillation (MJO) is the dominant mode of atmospheric intraseasonal variability and the cornerstone for subseasonal prediction of extreme weather events. Climate modeling and prediction of MJO remain a big challenge, partially due to lack of understanding the MJO diversity. Here, we delineate observed MJO diversity by cluster analysis of propagation patterns of MJO events, which reveals four archetypes: standing, jumping, slow eastward propagation, and fast eastward propagation. Each type exhibits distinctive east-west asymmetric circulation and thermodynamic structures. Tight coupling between the Kelvin wave response and major convection is unique for the propagating events, while the strength and length of Kelvin wave response distinguish slow and fast propagations. The Pacific sea surface temperature anomalies can affect MJO diversity by modifying the Kelvin wave response and its coupling to MJO convection. The results shed light on the mechanisms responsible for MJO diversity and provide potential precursors for foreseeing MJO propagation.
4
Toutain, P. L., P. G. Marnet, M. P. Laurentie, R. Garcia-Villar e Y. Ruckebusch. "Direction of uterine contractions during estrus in ewes: a reevaluation". American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 249, n. 4 (1 ottobre 1985): R410—R416. http://dx.doi.org/10.1152/ajpregu.1985.249.4.r410.
Testo completoAbstract (sommario):
In four ewes direction of propagation of uterine contractions was evaluated using an electromyographic technique during 15 entire estrous periods; 120,101 propagations were analyzed. When horns were considered separately 89.9% of all propagations were classified into three main modes: ascending (34.3%), descending (59.85%), and divergent (5.85%). When both horns were analyzed simultaneously, horn's synchronicity was observed in most instances; on this basis, eight modes of propagation were identified of which three accounted for two-thirds of all propagation: synchronous descending (24.9%), reciprocal propagation (descending on one horn and then ascending on contralateral horn) (22.1%), and isolated descending propagation (18.0%). A time-dependent pattern of propagation throughout estrus was clearly identified, the percentage of ascending propagations reaching a minimum (16.5%) and the percentage of descending propagation reaching a maximum (77%) at peak uterine motility level. By considering both direction of uterine propagation and cervical mechanical activity, a new hypothesis concerning two aspects of sperm transport (speed and mechanism) was formulated. It is hypothesized that the high prevalence of descending propagations is important to reduce sperm cell population by selecting the most vigorous spermatozoa; such selection is possible when the mechanical cervical activity is low or absent (cervix open); when cervical mechanical activity is high (cervix closed), it is suggested that both descending and ascending propagations participate in sperm transport by back and forth motion of luminal fluid within the uterine lumen.
5
Cohen, David, Christopher Jefferson e Karen Petrie. "A Theoretical Framework for Constraint Propagator Triggering". Proceedings of the International Symposium on Combinatorial Search 7, n. 1 (1 settembre 2021): 19–27. http://dx.doi.org/10.1609/socs.v7i1.18388.
Testo completoAbstract (sommario):
CSP instances are commonly solved by backtracking search combined with constraint propagation. During search, constraint solvers aim to remove any literals (variable-value pair) that can be shown not to be part of any solution. This literal removal, called propagation, is the beating heart of modern constraint solvers. A significant proportion of the runtime of propagating constraint solvers is spent running propagation algorithms. Therefore any mechanism for reducing how frequently propagators are called leads directly to significant performance improvements. One family of popular techniques is dynamic triggering — these techniques aim to avoid invoking a propagator when it would remove no literals. While this technique has been successful in practice, it has not yet been studied theoretically. This paper provides a theoretical framework for understanding when dynamic triggering will be successful. In particular, we prove when a literal deletion does not require a propagator to be executed. To achieve this, we describe supports: a support for a constraint is a set of literals whose presence in a search state ensures that propagating the constraint will not remove any literals. Therefore running the propagator when a literal outside the support is deleted is a waste of time. By characterising supports and giving a definition of dynamic and static supports for the CSP, we provide the framework for a proper analysis. We show how the number of triggers required for different constraints varies widely. For some constraints, dynamic triggering allows very small supports, for others the number of required supports is provably large.
6
Stovas, Alexey, Yuriy Roganov e Vyacheslav Roganov. "Interaction between P, S1 and S2 waves in multilayered periodic monoclinic media at low frequencies". Geophysical Journal International 220, n. 3 (5 dicembre 2019): 1947–55. http://dx.doi.org/10.1093/gji/ggz551.
Testo completoAbstract (sommario):
SUMMARY Application of the Floquet theorem and the matrix propagator method reduces the problem of the plane wave propagation in a periodically layered anisotropic media, to analysis of the properties of stationary envelopes of different wave modes propagating up- and downwards. We analyse the interchanging of stop- and pass-bands and their structure at low frequencies for a periodically layered medium with monoclinic symmetry. The analysis shows the effect of interaction between P,S1 and S2 wave multipliers for stop- and pass-band structure and gives insight into the wave propagation in vertically heterogeneous anisotropic media which is important in modelling and interpretation of seismic data.
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Kohles, S. S., J. R. Bowers, A. C. Vailas e R. Vanderby. "Ultrasonic Wave Velocity Measurement in Small Polymeric and Cortical Bone Specimens". Journal of Biomechanical Engineering 119, n. 3 (1 agosto 1997): 232–36. http://dx.doi.org/10.1115/1.2796085.
Testo completoAbstract (sommario):
A system was refined for the determination of the bulk ultrasonic wave propagation velocity in small cortical bone specimens. Longitudinal and shear wave propagations were measured using ceramic, piezoelectric 20 and 5 MHz transducers, respectively. Results of the pulse transmission technique were refined via the measurement of the system delay time. The precision and accuracy of the system were quantified using small specimens of polyoxymethylene, polystyrene-butadiene, and high-density polyethylene. These polymeric materials had known acoustic properties, similarity of propagation velocities to cortical bone, and minimal sample inhomogeneity. Dependence of longitudinal and transverse specimen dimensions upon propagation times was quantified. To confirm the consistency of longitudinal wave propagation in small cortical bone specimens (<1.0 mm), cut-down specimens were prepared from a normal rat femur. Finally, cortical samples were prepared from each of ten normal rat femora, and Young’s moduli (Eii), shear moduli (Gij), and Poisson ratios (vij) were measured. For all specimens (bone, polyoxymethylene, polystyrene-butadiene, and high-density polyethylene), strong linear correlations (R2 > 0.997) were maintained between propagation time and distance throughout the size ranges down to less than 0.4 mm. Results for polyoxymethylene, polystyrene-butadiene, and high-density polyethylene were accurate to within 5 percent of reported literature values. Measurement repeatability (precision) improved with an increase in the wave transmission distance (propagating dimension). No statistically significant effect due to the transverse dimension was detected.
8
Kim, Hyo Jin, Sang Ho Lee e Moon Kyum Kim. "Prediction of Crack Propagation under Dynamic Loading Conditions by Using the Enhanced Point Collocation Meshfree Method". Key Engineering Materials 324-325 (novembre 2006): 1059–62. http://dx.doi.org/10.4028/www.scientific.net/kem.324-325.1059.
Testo completoAbstract (sommario):
An efficient and accurate numerical program with enhanced point collocation meshfree method is developed to simulate crack propagation under dynamic loading conditions. The enhanced meshfree method with point collocation formulation and derivative approximation in solids is presented. This study also presents the crack propagation criterion and computation of propagating direction, and the total structure of the numerical program named PCMDYC(Point Collocation Meshfree method for DYnamic Crack propagation). Several examples of crack propagation under dynamic loads are analyzed to simulate the arbitrary crack propagation under dynamic loads. The results show that PCMDYC predicts the propagating path of crack under dynamic loading conditions accurately and robustly.
9
Idol, Travis, Adel Youkhana e Renier Paul Santiago. "Vegetative and micropropagation of leucaena". Tropical Grasslands-Forrajes Tropicales 7, n. 2 (31 maggio 2019): 87–95. http://dx.doi.org/10.17138/tgft(7)87-95.
Testo completoAbstract (sommario):
Keynote paper presented at the International Leucaena Conference, 1‒3 November 2018, Brisbane, Queensland, Australia.To effectively utilize sterile hybrids of leucaena, efficient protocols for vegetative propagation are needed that meet different user requirements and capabilities. We developed and compared methods for propagating several sterile hybrids of leucaena and compared them with each other and with propagation via seeds for variety K636. Methods included air-layers, rooted cuttings, grafting and tissue culture (micropropagation). All methods required 14‒20 weeks from generation of new shoots on the stock plant to production of rooted plantlets ready to outplant as compared with 6‒8 weeks for seedlings of K636. Successful rooting was highest for air-layers and rooted cuttings. Grafting had lower success owing to a higher skill requirement for the propagator. Tissue culture showed promise, but use of field-grown material was limited by microbial contamination of propagation media. Rooted cuttings are the best option presently for operational-scale propagation, but the method requires a mist system or a carefully controlled non-mist environment. If an effective method can be developed, grafting of young shoots onto a seedling rootstock is an alternative that retains the advantages of a seedling tap root and requires fewer resources than rooted cuttings or tissue culture.
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Hamabata, Hiromitsu, Tomikazu Namikawa e Kazuhiro Mori. "The effect of lower-hybrid waves on the propagation of hydromagnetic waves". Journal of Plasma Physics 40, n. 2 (ottobre 1988): 337–51. http://dx.doi.org/10.1017/s0022377800013313.
Testo completoAbstract (sommario):
Propagation characteristics of hydromagnetic waves in a magnetic plasma are investigated using the two-plasma fluid equations including the effect of lower-hybrid waves propagating perpendicularly to the magnetic field. The effect of lower-hybrid waves on the propagation of hydromagnetic waves is analysed in terms of phase speed, growth rate, refractive index, polarization and the amplitude relation between the density perturbation and the magnetic-field perturbation for the cases when hydromagnetic waves propagate in the plane whose normal is perpendicular to both the magnetic field and the propagation direction of lower-hybrid waves and in the plane perpendicular to the propagation direction of lower-hybrid waves. It is shown that hydromagnetic waves propagating at small angles to the propagation direction of lower-hybrid waves can be excited by the effect of lower-hybrid waves and the energy of excited waves propagates nearly parallel to the propagation direction of lower-hybrid waves.
11
Molas, Roman, Halina Borkowska e Barbara Sawicka. "Wieloletnie użytkowanie ślazowca pensylwańskiego – wartościowego źródła biomasy". Agronomy Science 76, n. 1 (12 maggio 2021): 97–116. http://dx.doi.org/10.24326/as.2021.1.7.
Testo completoAbstract (sommario):
Next-generation biomass feedstocks are needed to optimize sustainability in a wide range of soils and climates. Species that has been recently noticed in Europe is Virginia fanpetals (Sida hermaphrodita L. Rusby). A critical question with research of this species is its field propagation. A long-term (2003–2012), field experiment was conducted to determine the impact of propagation method on yields and productivity this species. The hypothesis was higher yields of S. hermaphrodita biomass from vegetative propagations than from generative propagations, also over the long term. On average, from first 10 years of lifespan of Virginia fanpetals (2003–2012), biomass dry matter (DM) yields were significantly higher by vegetative propagation (16.8 Mg ha–1) as for generative (10.9 Mg ha–1). The average gross energy yield obtained by the vegetative propagation reached 304 GJ ha–1 while by the generative propagation was 196 GJ ha–1. The determined heat of combustion reached 18.1 GJ Mg–1 DM, the ash content was 28 g kg–1, and the nitrogen (N), sulphur (S), and chlorine (Cl) contents were 1.9 g kg–1, 0.52 g kg–1 and 0.23 g kg–1, respectively, regardless of propagation methods.
12
Huang, Lian-Jie, e Michael C. Fehler. "Accuracy analysis of the split-step Fourier propagator: Implications for seismic modeling and migration". Bulletin of the Seismological Society of America 88, n. 1 (1 febbraio 1998): 18–29. http://dx.doi.org/10.1785/bssa0880010018.
Testo completoAbstract (sommario):
Abstract The split-step Fourier propagator is a one-way wave propagation method that has been widely used to simulate primary forward and backward (reflected) deterministic/random wave propagation due to its fast computational speed and limited computer memory requirement. The method is useful for rapid modeling of seismic-wave propagation in heterogeneous media where forward scattered waveforms can be considered to be dominant or reverberations can be ignored. The method is based on a solution to the one-way wave equation that requires expanding the square root of an operator and splitting of the resulting noncommutative operators to allow calculation by transferring wave fields between the space and wavenumber domains. Previous analysis of the accuracy of the method has focused on the error related to only a portion of the approximations involved in the propagator. To better understand the accuracy of the propagator, we present a complete formal and numerical accuracy analyses. Our formal analysis indicates that the dominant error of the propagator increases as the first order in the marching interval. We show that nonsymmetrically and symmetrically split-step marching solutions have the same first-order error term. Their second- and third-order error terms are similar. Therefore, the differences between the accuracy of different split-step marching solutions are insignificant. This conclusion is confirmed by our numerical tests. The relation among the phase error of the split-step Fourier propagator, relative velocity perturbation, and propagation angle is numerically studied. The results suggest that the propagator is accurate for up to a 60° propagation angle from the main propagation direction for media with small relative velocity perturbations (10%).
13
Wang, Bin, e Sun-Seon Lee. "MJO Propagation Shaped by Zonal Asymmetric Structures: Results from 24 GCM Simulations". Journal of Climate 30, n. 19 (1 settembre 2017): 7933–52. http://dx.doi.org/10.1175/jcli-d-16-0873.1.
Testo completoAbstract (sommario):
Abstract Eastward propagation is an essential characteristic of the Madden–Julian oscillation (MJO). Yet, simulation of MJO propagation in general circulation models (GCMs) remains a major challenge and understanding the causes of propagation remains controversial. The present study explores why the GCMs have diverse performances in MJO simulation by diagnosis of 24 GCM simulations. An intrinsic linkage is found between MJO propagation and the zonal structural asymmetry with respect to the MJO convective center. The observed and realistically simulated MJO eastward propagations are characterized by stronger Kelvin easterly waves than Rossby westerly waves in the lower troposphere, which is opposite to the Gill pattern where Rossby westerly waves are 2 times stronger than Kelvin easterly waves. The GCMs simulating stronger Rossby westerly waves tend to show a stationary MJO. MJO propagation performances are robustly correlated with the quality of simulated zonal asymmetries in the 850-hPa equatorial zonal winds, 700-hPa diabatic heating, 1000–700-hPa equivalent potential temperature, and convective instability. The models simulating realistic MJO propagation are exemplified by an eastward propagation of boundary layer moisture convergence (BLMC) that leads precipitation propagation by about 5 days. The BLMC stimulates MJO eastward propagation by preconditioning and predestabilizing the atmosphere, and by generating lower-tropospheric heating and available potential energy to the east of precipitation center. The MJO structural asymmetry is generated by the three-way interaction among convective heating, moisture, and equatorial wave and boundary layer dynamics. In GCMs, differing convective heating representation could produce different MJO structural asymmetry, and thus different propagations. Diagnosis of structural asymmetry may help revealing the models’ deficiency in representing the complex three-way interaction processes, which involves various parameterized processes.
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Perviy, Bogdan. "Improving sgp4 orbit propagation". System technologies 6, n. 125 (27 dicembre 2019): 76–81. http://dx.doi.org/10.34185/1562-9945-6-125-2019-07.
Testo completoAbstract (sommario):
The review reflects a comparison between several studies on improving the orbit propagataion accuracy using space objects’ TLE-elements. The study is done to identify a technique that can be applied to enhance the SGP4 model despite increasing the propagation span. The method used in this study is by comparing the techniques that have been used by other researchers for the orbit propagation model. From the review that has been done, a beta regression technique is found to be a suitable technique.
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TUCCI, ROBERT R. "DIFFRACTION AND SQUEEZED LIGHT". International Journal of Modern Physics B 07, n. 26 (30 novembre 1993): 4403–37. http://dx.doi.org/10.1142/s0217979293003735.
Testo completoAbstract (sommario):
We discuss the effect of diffraction on squeezed light propagation. All electric fields concerned are approximated to be monochromatic and paraxial. We consider: (1)(propagation without gain) a squeezed signal propagating in free space, and (2)(propagation with gain) a squeezed signal propagating in a non-linear crystal which amplifies the signal by a process of frequency halving (degenerate parametric amplification). The pump beam required for this process is assumed to have a Gaussian amplitude profile. For propagation without gain, our expression for the final signal is exact, but for propagation with gain, it is given as a perturbative expansion. The lowest order term in the expansion neglects diffraction of the signal and assumes flat pump wavefronts. Higher order terms include these factors and thus improve the accuracy with which the signal’s transverse behavior is described. We present graphs showing the dependence of squeezing on pump and signal beam parameters. We also find and discuss approximate formulas that characterize these graphs in various regimes.
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Gong, Guangyu, Rui Duan e Kunde Yang. "Segmented propagation model for the paths and travel times of surface duct leaky signals". Journal of the Acoustical Society of America 156, n. 3 (1 settembre 2024): 1476–88. http://dx.doi.org/10.1121/10.0028378.
Testo completoAbstract (sommario):
In the deep ocean environment with a surface duct, sound propagating within the duct leaks into the geometric shadow zone below it. However, the propagation paths and time of these leaky parts have not been fully characterized. This paper investigates the mechanism of surface duct leaky (SDL) signals based on normal mode theory. It reveals that SDL signals are caused by specific modes with grazing angles close to zero at the bottom of the surface duct. Combining the theory of diffracted sound rays, the study proposes a Segmented Propagation model (SPM) for SDL signals. The propagation paths of SDL signals are divided into three segments: S1, which extends from the source to the surface duct; S2, the segment propagating within the surface duct; and S3, the segment leading from the surface duct to the receiver. The proposed SPM describes the propagation mechanism of SDL signals and allows for precise calculation of their propagation time. Experimental data from the western Pacific are used to verify the SPM.
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Gorbunov, Michael E., Oksana A. Koval, Victor A. Kulikov e Alexey E. Mamontov. "Method of spherical phase screens for the modeling of propagation of diverging beams in inhomogeneous media". ITM Web of Conferences 30 (2019): 15027. http://dx.doi.org/10.1051/itmconf/20193015027.
Testo completoAbstract (sommario):
The phase-screen (split-step) method is widely used for the modeling of wave propagation in inhomogeneous media. Most known is the method of flat phase screens. An optimized approach based on cylindrical phase screen was introduced for the 2-D modeling of radio occultation sounding of the Earth’s atmosphere. In this paper, we propose a further generalization of this method for the 3-D problem of propagation of diverging beams. Our generalization is based on spherical phase screens. In the paraxial approximation, we derive the formula for the vacuum screen- to-screen propagator. We also derive the expression for the phase thickness of a thin layer of an isotropic random media. We describe a numerical implementation of this method and give numerical examples of its application for the modeling of a diverging laser beam propagating on a 25 km long atmospheric path.
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Yang, Zhen Feng. "Numerical Simulations of Two Four-Petal Gaussian Beams Propagating in Strongly Nonlocal Media". Advanced Materials Research 989-994 (luglio 2014): 1909–12. http://dx.doi.org/10.4028/www.scientific.net/amr.989-994.1909.
Testo completoAbstract (sommario):
The interaction of two four-petal Gaussian beams propagating in strongly nonlocal nonlinear media is investigated. The results show that the intensity evolution of two beams during their propagation is periodical, which is similar to that of a single beam propagation. However the combined optical field of two beams during propagation is more complicated than that of a single beam. During propagation, the two beams are attracted each other, and at the superposed region of two optical fields, the interference fringes appear. The influences of different beam orders and different input powers on the propagation properties are also discussed.
19
Cheng, Yifeng, Lu Wang e Tim Li. "Causes of Interdecadal Increase in the Intraseasonal Rainfall Variability over Southern China around the Early 1990s". Journal of Climate 33, n. 21 (1 novembre 2020): 9481–96. http://dx.doi.org/10.1175/jcli-d-20-0047.1.
Testo completoAbstract (sommario):
AbstractThe southern China (SC) summer rainfall exhibits prominent intraseasonal variability, which exhibits a significant increase in the early 1990s with the turning point at 1993. The SC intraseasonal rainfall events could be divided into three categories according to different propagations, including the southward-propagating (SP) events, the northwestward-propagating (NWP) events, and the northward-propagating (NP) events. This study explores the causes of the observed interdecadal increase in the intraseasonal rainfall variability over SC by comparing the SC intraseasonal rainfall events of each category between the former decadal period (P1) and the later decadal period (P2). The result indicates that such interdecadal change is due to the more frequent NP events coming from the South China Sea (SCS). Based on the moisture and vorticity budget analysis, it is revealed that the summer mean southerly wind in the middle to lower troposphere is the dominant factor of the northward propagation over the SCS, as it could induce positive meridional moisture and vorticity advection anomalies ahead of the convection. A marked interdecadal enhancement of the summer mean southerly wind over the SCS is the cause of more frequent occurrence of NP events over SC, as it provides more favorable conditions for the northward propagation. The change of the atmospheric instability over the SCS where the NP convection perturbation originates was also investigated, but no significant change was found.
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ANDERSON, A. R. A., e B. D. SLEEMAN. "WAVE FRONT PROPAGATION AND ITS FAILURE IN COUPLED SYSTEMS OF DISCRETE BISTABLE CELLS MODELLED BY FITZHUGH-NAGUMO DYNAMICS". International Journal of Bifurcation and Chaos 05, n. 01 (febbraio 1995): 63–74. http://dx.doi.org/10.1142/s0218127495000053.
Testo completoAbstract (sommario):
We discuss wave front propagation and its failure for the discrete FitzHugh-Nagumo system. We show, using a new comparison theorem, that wave front propagation is blocked for d, the coupling coefficient, sufficiently small and propagation must occur for d sufficiently large. Our numerical simulations confirm the analytical findings. We also give a numerical estimate for the speed of propagating waves as a function of d.
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Hammad, F. T., B. Stephen, L. Lubbad, J. F. B. Morrison e W. J. Lammers. "Macroscopic electrical propagation in the guinea pig urinary bladder". American Journal of Physiology-Renal Physiology 307, n. 2 (15 luglio 2014): F172—F182. http://dx.doi.org/10.1152/ajprenal.00215.2014.
Testo completoAbstract (sommario):
There is little knowledge about macroscopic electrical propagation in the wall of the urinary bladder. Recording simultaneously from a large number of extracellular electrodes is one technology that could be used to study the patterns of macroscopic electrical propagations. The urinary bladders from 14 guinea pigs were isolated and placed in an organ bath. A 16 × 4-electrode array was positioned at various sites on the serosal bladder surface, and recordings were performed at different intravesical volumes. In four experiments, carbachol (CCH; 10−6 M), nifedipine (10 mM), or tetrodotoxin (TTX; 10−6 M) was added to the superfusing fluid. After the experiments, the extracellular signals were analyzed and propagation maps were constructed. Electrical waves were detected at all sites on the bladder surface and propagated for a limited distance before terminating spontaneously. The majority of waves (>90%) propagated in the axial direction (i.e., from dome to base or vice versa). An increase in vesicle volume significantly decreased the conduction velocity (from 4.9 ± 1.5 to 2.7 ± 0.7 cm/s; P < 0.05). CCH increased, nifedipine decreased, while TTX had little effect on electrical activities. In addition, a new electrical phenomenon, termed a “patch,” was discovered whereby a simultaneous electrical deflection was detected across an area of the bladder surface. Two types of electrical activities were detected on the bladder surface: 1) electrical waves propagating preferentially in the axial direction and 2) electrical patches. The propagating electrical waves could form the basis for local spontaneous contractions in the bladder during the filling phase.
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Aoki, Y., T. Matsuyama, Yasuji Oda, Kenji Higashida e Hiroshi Noguchi. "Effects of Hydrogen Gas Environment on Non-Propagation Phenomena of a Type 304 Austenitic Stainless Steel". Key Engineering Materials 297-300 (novembre 2005): 927–32. http://dx.doi.org/10.4028/www.scientific.net/kem.297-300.927.
Testo completoAbstract (sommario):
In order to investigate the hydrogen gas effect on non-propagation phenomena of a type 304 austenitic stainless steel, fatigue tests with in-situ observation using a Scanning Laser Microscope were performed in air, in 0.18MPa hydrogen gas and in 0.18MPa nitrogen gas. A nonpropagating crack was observed during the fatigue test in air. At almost the same stress level of non-propagating in air, non-propagating cracks were also observed in fatigue tests in hydrogen and in nitrogen. Stress level of the non-propagation is not sufficiently different in the three environments. However, the process up to non-propagation differs from each other, for example, the crack path and debris.
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Su, Zhiyuan, Mingchu Li, Xinxin Fan, Xing Jin e Zhen Wang. "Research on Trust Propagation Models in Reputation Management Systems". Mathematical Problems in Engineering 2014 (2014): 1–16. http://dx.doi.org/10.1155/2014/536717.
Testo completoAbstract (sommario):
Feedback based reputation systems continue to gain popularity in eCommerce and social media systems today and reputation management in large social networks needs to manage cold start and sparseness in terms of feedback. Trust propagation has been widely recognized as an effective mechanism to handle these problems. In this paper we study the characterization of trust propagation models in the context of attack resilience. We characterize trust propagation models along three dimensions: (i) uniform propagation and conditional propagation, (ii) jump strategies for breaking unwanted cliques, and (iii) decay factors for differentiating recent trust history from remote past history. We formally and experimentally show that feedback similarity is a critical measure for countering colluding attacks in reputation systems. Without feedback similarity guided control, trust propagations are vulnerable to different types of colluding attacks.
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Chen, Ge, Xiaoyan Chen e Chuanchuan Cao. "Divergence and Dispersion of Global Eddy Propagation from Satellite Altimetry". Journal of Physical Oceanography 52, n. 4 (aprile 2022): 705–22. http://dx.doi.org/10.1175/jpo-d-21-0122.1.
Testo completoAbstract (sommario):
Abstract It is well understood that isolated eddies are presumed to propagate westward intrinsically at the speed of the annual baroclinic Rossby wave. This classic description, however, is known to be frequently violated in both propagation speed and its direction in the real ocean. Here, we present a systematic analysis on the divergence of eddy propagation direction (i.e., global pattern of departure from due west) and dispersion of eddy propagation speed (i.e., zonal pattern of departure from Rossby wave phase speed). Our main findings include the following: 1) A global climatological phase map (the first of its kind to our knowledge) indicating localized direction of most likely eddy propagation has been derived from 28 years (1993–2020) of satellite altimetry, leading to a leaf-like full-angle pattern in its overall divergence. 2) A meridional deflection map of eddy motion is created with prominent equatorward/poleward deflecting zones identified, revealing that it is more geographically correlated rather than polarity determined as previously thought (i.e., poleward for cyclonic eddies and equatorward for anticyclonic ones). 3) The eddy–Rossby wave relationship has a duality nature (waves riding by eddies) in five subtropical bands centered around 27°N and 26°S in the two hemispheres, outside which their relationship has a dispersive nature with dominant waves (eddies) propagating faster in the tropical (extratropical) oceans. Current, wind, and topographic effects are major external forcings responsible for the observed divergence and dispersion of eddy propagations. These results are expected to make a significant contribution to eddy trajectory prediction using physically based and/or data-driven models.
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Zhao, Wan Chun, Chen Wang, Ting Ting Wang e Bing Guan. "Calculation Model Study on Damaging Stress of Hydraulically Created Fracture Propagation". Applied Mechanics and Materials 275-277 (gennaio 2013): 238–41. http://dx.doi.org/10.4028/www.scientific.net/amm.275-277.238.
Testo completoAbstract (sommario):
In order to describe hydraulically created fracture propagation’s characteristics of rock matrix exactly, in this paper, establishing a stress field ‘s calculation model of fracturing propagation tip , obtaining numerical method of fracturing propagation’s characteristics based on damaging and describing fracturing propagation’s characteristics combined with method of finite element. Research shows that the corrigendum between stress field ‘s calculation model of fracturing propagation tip and practical engineering are 0.64 percent and 1.43 percent respectively. Compared with the traditional method, the result is more exactly.
26
Sinha, Bablu, e Brenda Topliss. "A Description of Interdecadal Time-Scale Propagating North Atlantic Sea Surface Temperature Anomalies and Their Effect on Winter European Climate, 1948–2002". Journal of Climate 19, n. 7 (1 aprile 2006): 1067–79. http://dx.doi.org/10.1175/jcli3646.1.
Testo completoAbstract (sommario):
Abstract Eastward-propagating interdecadal time-scale sea surface temperature (SST) winter anomalies have been shown to exist at the North Atlantic subpolar/subtropical gyre boundary. Heat flux and surface air temperature signatures of these anomalies are investigated using satellite- and ship-based SST observations and atmospheric reanalysis. Using bandpass filter analysis, retaining periods between 9 and 25 yr, a succession of coherent propagating SST anomalies is identified. The size, speed, propagation path, and decay characteristics of propagating anomalies detected during the period 1948–2002 are documented. The behavior of the propagations changes between the periods 1948–70 and 1970–2002. In the former period, SST anomalies propagated from the east coast of North America to the British Isles in ∼10 yr. The anomalies displayed a well-defined life cycle, growing in the western basin (west of 40°W) and decaying in the eastern basin. During the period 1970–2002, SST anomalies did not propagate deep into the eastern basin, but grew in the western basin and then ceased propagating. Oceanic anomalies have a comparable marked signature in surface sensible and latent heat fluxes and in surface air temperature. Winter surface heat flux anomalies act to amplify SST anomalies during the middle of their lifetimes, normally in the west-central Atlantic. At other times, heat flux anomalies are associated with decay of anomalies. Surface heat fluxes do not always act to cause propagation, and it is likely that other processes such as advection play a role in the propagation mechanism. North European winter surface air temperatures are raised or lowered by up to ±0.5°C over decadal time scales (∼1/3 of the total variation over the United Kingdom) when an SST anomaly reaches the eastern boundary. A variety of processes can cause SST variation on decadal time scales at the eastern boundary, but in the 1950s and 1960s the variability at these periods was the signature of features that had propagated across the Atlantic from the North American coast.
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Bakker, Peter M. "A stable one-way wave propagator for VTI media". GEOPHYSICS 74, n. 5 (settembre 2009): WB3—WB17. http://dx.doi.org/10.1190/1.3196818.
Testo completoAbstract (sommario):
For the purpose of one-way wave-equation imaging, a pseudoscreen propagator is developed for transversely isotropic media with vertical axes of symmetry. The phase shift for propagation through a depth slice is decomposed into three terms: a Gazdag phase shift for propagation in a laterally homogeneous reference medium, a correction for lateral variability of vertical propagation, and a remaining wide-angle term for oblique directions of propagation. Based on rational function approximation for this remaining wide-angle term, a Fourier finite-difference (FFD) approach with four-way splitting is applied. Fourth-order Padé approximation is unsatisfactory in anelliptic media for large propagation angles with respect to the vertical direction. Therefore, a method of coefficient optimization is developed in conjunction with a method of choosing an adequate homogeneous reference medium in a depth slice. By symmetrizing the finite-difference operators, and because of the choice of the optimized coefficients, the propagator is stable in the sense that the least-squares norm of the wavefield, measured for a frequency-depth slice, does not grow with increasing depth of propagation. A small amount of artificial damping is applied to suppress artifacts that appear at the critical angle defined by the velocities in the reference medium and the actual medium. Synthetic examples confirm that good kinematic accuracy is achieved for a wide range of propagation angles (typically up to 60°).
28
Nian, Fuzhong, Rendong Liu e Anhui Cong. "An incentive mechanism model based on the correlation between neighbor behavior and distance". International Journal of Modern Physics C 31, n. 11 (1 ottobre 2020): 2050161. http://dx.doi.org/10.1142/s0129183120501612.
Testo completoAbstract (sommario):
In this study, the incentive is defined based on feedback mechanism promoting propagation, and a novel model of behavior propagation is proposed based on feedback mechanism to investigate behavior propagation. In this model, the incentive includes the distance among individuals and the set of state and the influence of node is decided by the incentive and node degree, which explore the propagation effect under different network. The experimental results show the incentive and the propagation have positive correlation, and the propagating effect is determined by the network attribute. At the same time, the greater the degree of the node, the more obvious the incentive effect. Incentive results of nodes will continuously decline until they suffer second incentive.
29
Wen, Zhiping, Shutao Peng, Jing Yang, Jun Deng, Hanqing He e Tong Wang. "Analysis of the Propagation Characteristic of Subsynchronous Oscillation in Wind Integrated Power System". Energies 12, n. 6 (20 marzo 2019): 1081. http://dx.doi.org/10.3390/en12061081.
Testo completoAbstract (sommario):
This paper proposes oscillation propagation factors to analyze power oscillations caused by the interharmonics of doubly fed induction generators (DFIG) at different points in the power system. First, a dynamic model of the DIFG is built, including the asynchronous generator, its transmission system, converters and the control systems. Then, the state space expression is formed by deducing the input and output matrices. From this, the oscillation propagation factor is proposed and denoted to exhibit the propagation mechanism of interharmonics in the view of frequency domain, by deducing the multi-input-multi-output transfer functions matrix. Along with this, the sensitivity of propagation is calculated for adjusting the parameters to block the oscillation propagating path. Finally, the modified four machine system with two DFIGs and the New-England 39 bus system with two DFIGs is used as a test system to verify the effectiveness of the oscillation propagation factor. From this the simulation results demonstrate that the subsynchronous interharmonics of DFIGs injected into the grid will propagate to the different points of the system and results in oscillation of the power. The oscillation propagation factor could quantize the oscillation magnitude propagating from one point to other point in the wind integrated power system.
30
Jovanoski, Zlatko, e Rowland A. Sammut. "Propagation of Cylindrically Symmetric Gaussian Beams in a Higher-Order Nonlinear Medium". Journal of Nonlinear Optical Physics & Materials 06, n. 02 (giugno 1997): 209–34. http://dx.doi.org/10.1142/s0218863597000186.
Testo completoAbstract (sommario):
The propagation of a cylindrically symmetric Gaussian beam in a cubic-quintic nonlinear medium is analysed via a variational approach. Explicit conditions for stationary beam propagation are determined and their stability to symmetric perturbation of the spot width is established. Approximate analytical solutions are secured for the spot width modulation with propagation distance. A comparison is made with beams propagating in a medium exhibiting a two-level saturation.
31
Lin, Ailan, e Tim Li. "Energy Spectrum Characteristics of Boreal Summer Intraseasonal Oscillations: Climatology and Variations during the ENSO Developing and Decaying Phases*". Journal of Climate 21, n. 23 (1 dicembre 2008): 6304–20. http://dx.doi.org/10.1175/2008jcli2331.1.
Testo completoAbstract (sommario):
Abstract The geographic-dependence characteristics of the energy spectrum of the boreal summer intraseasonal oscillation (BSISO; May–October) over the Indo–western Pacific region were analyzed using 25-yr (1979–2003) observational data. The BSISO energy spectrum distribution exhibits a distinctive regional characteristic. The stationary and eastward-propagating modes are most pronounced at the equator (5°S–5°N), while the westward-propagating modes are dominant in the off-equatorial region (10°–20°N). While the eastward intraseasonal oscillation (ISO) spectrum agglomerates on the 30–60-day period and zonal wavenumber 1, the westward mode covers wider spatial (wavenumber) and temporal (period) range. Along the Arabian Sea, Bay of Bengal, and South China Sea (SCS) latitudes, the dominant wavenumber 1 mode is the eastward (westward) propagation at the 30–60-day (10–20 day) period; for zonal wavenumber 2, the dominant mode is the westward propagation at both the 30–60-day and 10–20-day periods. Compared to the absolute amplitude of both zonal and meridional mode energy spectrum, northward propagation is the most predominant mode in boreal summer over the Indo–western Pacific regions. The strongest northward-propagating BSISO signal appears in the eastern tropical Indian Ocean. The variation of BSISO differs significantly in the El Niño and La Niña developing and decaying phases. During the El Niño (La Niña) developing summer, the eastward propagation is enhanced (weakened) at the equator, while the northward propagation is also strengthened (weakened) over the western Pacific (east of 140°E). During the El Niño (La Niña) decaying summer, the eastward propagation weakens (strengthens) at the equator, opposite to that in the developing summer; the westward propagation off the equator and the northward propagation over SCS and the western Pacific are suppressed (enhanced). The amplitude of the BSISO variation is stronger in the decaying summer than that in the developing summer. This asymmetry in BSISO variations is primarily attributed to the asymmetry of the background mean flow change associated with the developing and decaying phases of ENSO.
32
Barrio, R., M. Rodríguez, A. Abad e S. Serrano. "Uncertainty propagation or box propagation". Mathematical and Computer Modelling 54, n. 11-12 (dicembre 2011): 2602–15. http://dx.doi.org/10.1016/j.mcm.2011.06.036.
Testo completo
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Yang, Jun Ru, Z. Q. Li, C. Z. Huang, X. F. Wang e G. C. Wang. "Research on the Propagation of the Crack Inclined across the Interface in the Cermet Cladding Part". Materials Science Forum 697-698 (settembre 2011): 430–35. http://dx.doi.org/10.4028/www.scientific.net/msf.697-698.430.
Testo completoAbstract (sommario):
A new comparative propagation property parameter CP suitable to judge the propagation of the interface crack in the cladding part is proposed. The propagation criterion for the crack inclined across the interface is established. The theoretical research on the CPxA and CPxB of this interface crack propagating in the clad and substrate separately is carried out. The propagation law of the interface crack in the cermet cladding part is investigated with an example. The research results show that, within the ranges of the studied parameters, CPxA is bigger than CPxB, and that the crack initially propagates in the clad.
34
Yang, J. R., X. F. Wang, Y. K. Zhang, Z. Q. Li e C. Z. Huang. "Research on the Propagation of the Crack Parallel to and Lying on the Interface in the Cermet Cladding Part". Advanced Materials Research 426 (gennaio 2012): 287–92. http://dx.doi.org/10.4028/www.scientific.net/amr.426.287.
Testo completoAbstract (sommario):
Taking the interface crack in the cermet cladding part as the study object, a new comparative propagation property parameter (CPPP) CP suitable to judge the interface crack propagation direction in the cladding part is proposed. The interface crack propagation criterion is established. Based on it, the theoretical research on the parameters (CP1, CP2 and CPi) for the crack parallel to and lying on the interface propagating to the clad, to the substrate, and along the interface is carried out. The interface crack propagation law is investigated with an example. The research results show that the crack will more easily deflect to the clad.
35
Buller, A. S., Yu V. Zelenetskaya, R. V. Litvinov e N. R. Melikhova. "Modulation instability of two TE modes in a thin left-handed film on a nonlinear right-handed substrate". Quantum Electronics 51, n. 11 (1 novembre 2021): 1030–37. http://dx.doi.org/10.1070/qel17647.
Testo completoAbstract (sommario):
Abstract The intramode wave beams in a thin left-handed film on a Kerr substrate are considered at a frequency near zero mode group velocity. Four coupled (1 + 1)-dimensional nonlinear Schrödinger equations, describing the interaction of forward and backward propagating beams with positive and negative group velocities, are derived. It is shown that self- and cross-phase modulation for four simultaneously propagating modes is possible only at strictly matched perturbations of their propagation constants, which is due to the contribution of spatial parametric mixing. The modulation instability of only two waveguide modes is analysed for different versions of their propagation. The specific features of modulation instability, related to the propagation of modes with negative group velocities, are investigated.
36
Kubáček, Lubomír. "Nonlinear error propagation law". Applications of Mathematics 41, n. 5 (1996): 329–45. http://dx.doi.org/10.21136/am.1996.134330.
Testo completo
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Jin, Hong Bin. "Numerical Simulation of Wave Propagation in Variable Cross-Section Bars". Advanced Materials Research 378-379 (ottobre 2011): 72–76. http://dx.doi.org/10.4028/www.scientific.net/amr.378-379.72.
Testo completoAbstract (sommario):
A model for wave propagation in variable cross-section bars is developed. Then a numerical simulation method based on CSPM is introduced. Furthermore the wave propagations in stepped bars and conical bars are simulated. The simulation results agree well with the analytical solutions, which demonstrate that the model can describe the wave propagation in variable cross-section bars precisely.
38
Mitu, Maria, Venera Giurcan, Codina Movileanu, Domnina Razus e Dumitru Oancea. "Propagation of CH4-N2O-N2 Flames in a Closed Spherical Vessel". Processes 9, n. 5 (12 maggio 2021): 851. http://dx.doi.org/10.3390/pr9050851.
Testo completoAbstract (sommario):
Flammable fuel-N2O mixtures raise safety and environmental protection issues in areas where these mixtures are used (such as: industry, research, internal combustion engines). Therefore, it is important to know their laminar combustion velocities and propagation speeds—important safety parameters for design of active protection devices against gas explosions and corresponding safety recommendations. In this paper, the laminar combustion velocities of N2-diluted CH4-N2O flames, obtained in experiments on outwardly propagating flames, at various initial pressures (within 0.5–2.0 bar) and room temperature, are reported. The experiments were made in a 0.5 L spherical cell with central ignition. The laminar combustion velocities were calculated from the constants of cubic law of flame propagation during the early stage of closed cell explosions and the expansion coefficients of unburned flammable mixtures, using the adiabatic model of the flame propagation. The expansion coefficients were determined from equilibrium calculations on flames propagating under isobaric conditions. The laminar combustion velocities were compared with data reported in the literature. Using the laminar combustion velocities and the expansion coefficients, the propagation speeds of N2-diluted CH4-N2O flames were calculated. Both laminar combustion velocities and propagation speeds decrease with the initial pressure increase.
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Ambrosio, Benjamin, e Jean-Pierre Françoise. "Propagation of bursting oscillations". Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 367, n. 1908 (13 dicembre 2009): 4863–75. http://dx.doi.org/10.1098/rsta.2009.0143.
Testo completoAbstract (sommario):
We investigate a system of partial differential equations of reaction–diffusion type which displays propagation of bursting oscillations. This system represents the time evolution of an assembly of cells constituted by a small nucleus of bursting cells near the origin immersed in the middle of excitable cells. We show that this system displays a global attractor in an appropriated functional space. Numerical simulations show the existence in this attractor of recurrent solutions which are waves propagating from the central source. The propagation seems possible if the excitability of the neighbouring cells is above some threshold.
40
Evans, Colin G., Timothy Kang e Elizabeth C. Cropper. "Selective Spike Propagation in the Central Processes of an Invertebrate Neuron". Journal of Neurophysiology 100, n. 5 (novembre 2008): 2940–47. http://dx.doi.org/10.1152/jn.90807.2008.
Testo completoAbstract (sommario):
Within a neuron, spike propagation can occur in a complex manner, with spikes propagating into some processes but not others. We study this phenomenon in an experimentally advantageous mechanoafferent in Aplysia, neuron B21. B21 has two processes within the CNS. One is ipsilateral to the soma and is referred to as the lateral process. The second travels into the contralateral hemiganglion and is referred to as the contralateral process. Previously we characterized spike propagation to the lateral process, which is an output region that contacts follower motor neurons. Spikes fail to actively propagate to the lateral process when B21 is peripherally activated at its resting potential. This propagation failure can be relieved if the medial regions of B21 are centrally depolarized during peripheral activation. This study examines spike propagation to the contralateral process. We show that, unlike the lateral process, active spike propagation in the contralateral process occurs when B21 is peripherally activated at its resting membrane potential. Thus spike propagation occurs selectively, favoring the contralateral process. Interestingly, the contralateral process of one B21 is immediately adjacent to the medial region of the bilaterally symmetrical cell. The B21 neurons are electrically coupled, suggesting that spikes propagating in the contralateral process of one cell could modify propagation in the sister neuron. Consistent with this idea, we show that lateral process propagation failures observed when a single B21 is peripherally activated can be relieved by central coactivation of the contralateral cell. These results imply that stimuli that coactivate the B21 neurons bilaterally are more apt to generate afferent activity that is transmitted to followers than stimuli that activate one cell.
41
Zhu, Chang Shun, Guo Lin Wang, Ping Ping Li e Shang Wei Chen. "Crack-Propagating Direction of Tire Bead Rubber Determined by Jmax Criterion". Applied Mechanics and Materials 43 (dicembre 2010): 628–32. http://dx.doi.org/10.4028/www.scientific.net/amm.43.628.
Testo completoAbstract (sommario):
Three-dimensional crack propagating path of tire bead rubber was the premise to study the crack propagation direction of bead. For this reason, Jmax Criterion was put forward. Utilized J integral maximum (Jmax) to determine the crack propagation direction of rubber. Calculated J-integral values of different preset directions by Abaqus built-in algorithm, obtained J (θ) curve which showed the Jmax and direction angle (θ) by fitting simulation data. Using Abaqus to set up two different crack model of bead rubber and simulate the crack propagation path, the results was consistent with the real crack propagation direction of specimen test, validated the applicability of Jmax Criterion..
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Aine, Sandip, e Maxim Likhachev. "Truncated Incremental Search: Faster Replanning by Exploiting Suboptimality". Proceedings of the AAAI Conference on Artificial Intelligence 27, n. 1 (30 giugno 2013): 16–24. http://dx.doi.org/10.1609/aaai.v27i1.8673.
Testo completoAbstract (sommario):
Incremental heuristic searches try to reuse their previous search efforts whenever these are available. As a result, they can often solve a sequence of similar planning problems much faster than planning from scratch. State-of-the-art incremental heuristic searches such as LPA*, D* and D* Lite all work by propagating cost changes to all the states on the search tree whose g-values (the costs of computed paths from the start) are no longer optimal. While such a complete propagation of cost changes is required to ensure optimality, the propagations can be stopped much earlier if we are looking for solutions within a given suboptimality bound. We present a framework called Truncated Incremental Search that builds on this observation, and uses a target suboptimality bound to efficiently restrict the cost propagations. Using this framework, we develop two algorithms, Truncated LPA* (TLPA*) and Truncated D* Lite (TD* Lite). We discuss their analytical properties and present experimental results for 2D and 3D (x, y, heading) path planning that show significant improvement in runtime over existing incremental heuristic searches when searching for close-to-optimal solutions. In addition, unlike typical incremental searches, Truncated Incremental Search is much less dependent on the proximity of the cost changes to the goal of the search due to the early termination of the cost change propagation.
43
Hao, Zhoucheng, Yanan Liu e Gang Wang. "Research on Data News Propagation Path Based on the Big Data Algorithm". International Transactions on Electrical Energy Systems 2022 (12 ottobre 2022): 1–13. http://dx.doi.org/10.1155/2022/5600004.
Testo completoAbstract (sommario):
News propagation originates from a person/location, dwelling with an event that grabs significance. News data propagation relies on telecommunication and big data for precise content distribution and mitigation of false news. Considering these factors, the event-dependent data propagation technique (EDPT) was introduced to improve the data precision. These data refer to the news information originating and propagating from digital media. The data analysis considers the external factors for fake information and precise projection medium for preventing multiviewed false circulations. In this technique, the liability of the information is analyzed using a linear pattern support vector classifier. The data modification and propagation changes are classified based on liability information across the circulation time. The SVM classifier identifies these two factors with close liability validation, preventing false data. The data accumulation and analysis rates for the abovementioned classifications are performed in the propagation process using the classifier hyperplane. This plane is updated from the previous propagation point from which the events are identified. The proposed technique’s performance is analyzed using propagation accuracy, precision, false rate, time, and rate.
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Morales, Felipe, Maria Richter, Vlad Olvo e Anton Husakou. "Propagator operator for pulse propagation in resonant media". Optics Express 29, n. 18 (25 agosto 2021): 29128. http://dx.doi.org/10.1364/oe.435012.
Testo completo
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Manoukian, E. B. "Electromagnetic propagation across a metal: the causal propagator". Journal of Electromagnetic Waves and Applications 30, n. 5 (16 marzo 2016): 677–88. http://dx.doi.org/10.1080/09205071.2016.1145075.
Testo completo
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Ajayamohan, R. S., Suryachandra A. Rao e Toshio Yamagata. "Influence of Indian Ocean Dipole on Poleward Propagation of Boreal Summer Intraseasonal Oscillations". Journal of Climate 21, n. 21 (1 novembre 2008): 5437–54. http://dx.doi.org/10.1175/2008jcli1758.1.
Testo completoAbstract (sommario):
Abstract The influence of the Indian Ocean dipole (IOD) on the poleward propagation of boreal summer intraseasonal oscillations (BSISOs) is examined using observed datasets. This study finds that coherent (incoherent) poleward propagation of precipitation anomalies from 5°S to 25°N are observed during negative (positive) IOD years. Disorganized poleward propagation of BSISO in the south equatorial Indian Ocean is observed during positive IOD years. The rationale behind such an anomaly in the poleward propagation of BSISO in contrasting IOD years is identified based on the theory of northward-propagating BSISO, which suggests the influential role of air–sea interaction on the genesis and propagation of BSISO. It is found that the mean structure of moisture convergence and meridional specific humidity distribution undergoes radical changes in contrasting IOD years, which in turn influences the meridional propagation of BSISO. This study assumes significance, considering the critical role of BSISO in modulating the seasonal mean summer monsoon rainfall.
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Brightman, B. K., Q. X. Li, D. J. Trepp e H. Fan. "Differential disease restriction of Moloney and Friend murine leukemia viruses by the mouse Rmcf gene is governed by the viral long terminal repeat." Journal of Experimental Medicine 174, n. 2 (1 agosto 1991): 389–96. http://dx.doi.org/10.1084/jem.174.2.389.
Testo completoAbstract (sommario):
Neonatal CxD2 (Rmcfr) and Balb/c (Rmcfs) mice inoculated with Moloney murine leukemia virus (M-MuLV) exhibited approximately equivalent time course and pathology for disease. CxD2 mice showed only slightly reduced presence of Moloney mink cell focus-forming virus (M-MCF) provirus as seen by Southern blot analysis compared to Balb/c mice. This lack of restriction for disease and spread of MCF was in sharp contrast to that seen for CxD2 mice inoculated with Friend murine leukemia virus (F-MuLV), where incidence of disease and propagation of MCFs were severely restricted, as previously reported. Inoculation of CxD2 mice with FM-MuLV, a recombinant F-MuLV virus containing M-MuLV LTR sequences (U3 and R), resulted in T cell disease of time course equal to that seen in Balb/c mice; there also was little restriction for propagation of MCFs. This indicated that presence of the M-MuLV long terminal repeat (LTR) was sufficient for propagation of MCFs in CxD2 mice. Differing restriction for F-MuLV vs. M-MuLV in CxD2 mice was explained on the basis of different "MCF propagator cells" for the two viruses. It was suggested that cells propagating F-MCF (e.g., erythroid progenitors) are blocked by endogenous MCF-like gp70env protein, whereas cells propagating M-MCF (e.g., lymphoid) do not express this protein on their surface. F-MuLV disease in CxD2 mice was greatly accelerated when neonates were inoculated with a F-MuLV/F-MCF pseudotypic mixture. However, F-MCF provirus was not detectable or only barely detectable in F-MuLV/F-MCF-induced tumors, suggesting that F-MCF acted indirectly in induction of these tumors.
48
Krishnamoorthi, A., e Pabitra Kumar Ghosh. "From Seed to Succulence: Mastering Dragon Fruit Propagation Techniques". Journal of Plant Biota 3, n. 1 (8 marzo 2024): 8–12. http://dx.doi.org/10.51470/jpb.2024.3.1.08.
Testo completoAbstract (sommario):
From Seed to Succulence: Mastering Dragon Fruit Propagation Techniques delves into the intricacies of propagating dragon fruit, a fascinating tropical fruit known for its exotic appearance and nutritional benefits. This article explores various propagation methods, including seed germination, stem cuttings, and grafting, shedding light on the challenges and rewards associated with each technique. By elucidating the principles of dragon fruit propagation and offering practical tips for success, this article equips growers with the knowledge and skills to cultivate thriving dragon fruit plants from seed to succulence. Whether you’re a novice enthusiast or an experienced horticulturist, this comprehensive guide serves as an invaluable resource for mastering the art of dragon fruit propagation and reaping the rewards of homegrown delicacies.
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Gao, Tingran, Shahab Asoodeh, Yi Huang e James Evans. "Wasserstein Soft Label Propagation on Hypergraphs: Algorithm and Generalization Error Bounds". Proceedings of the AAAI Conference on Artificial Intelligence 33 (17 luglio 2019): 3630–37. http://dx.doi.org/10.1609/aaai.v33i01.33013630.
Testo completoAbstract (sommario):
Inspired by recent interests of developing machine learning and data mining algorithms on hypergraphs, we investigate in this paper the semi-supervised learning algorithm of propagating ”soft labels” (e.g. probability distributions, class membership scores) over hypergraphs, by means of optimal transportation. Borrowing insights from Wasserstein propagation on graphs [Solomon et al. 2014], we re-formulate the label propagation procedure as a message-passing algorithm, which renders itself naturally to a generalization applicable to hypergraphs through Wasserstein barycenters. Furthermore, in a PAC learning framework, we provide generalization error bounds for propagating one-dimensional distributions on graphs and hypergraphs using 2-Wasserstein distance, by establishing the algorithmic stability of the proposed semisupervised learning algorithm. These theoretical results also shed new lights upon deeper understandings of the Wasserstein propagation on graphs.
50
Zhu, Jun, Hanhao Zhu, Jun Tang e Guangxue Zheng. "Researches on very low frequency acoustic signal propagation characteristics in different shallow elastic wedge bottoms". MATEC Web of Conferences 283 (2019): 02003. http://dx.doi.org/10.1051/matecconf/201928302003.
Testo completoAbstract (sommario):
Targeted at the issue of extremely low-frequency (<100Hz) acoustic propagation in complex shallow elastic bottom environments. The influence law of different complex elastic bottoms on the acoustic signal propagation at very low frequency by acoustic energy flux has been analyzed with the simulation, which is based on the finite element method. The elastic bottoms which have been studied are the shallow horizontal elastic bottom, and the up-sloping and the down-sloping elastic bottom. The results show that the acoustic signal propagating in the up-sloping and down-sloping elastic bottom environments is more complex than that propagating in the horizontal elastic bottom, and the acoustic energy leaking into those elastic bottoms has very different influence on the acoustic signal propagation, especially in the up-sloping bottom.