Skeleton Diagrams Research Articles

Seven Études on dynamical Keldysh model

We present a comprehensive pedagogical discussion of a family of models describing the propagation of a single particle in a multicomponent non-Markovian Gaussian random field. We report some exact results for single-particle Green’s functions, self-energy, vertex part and T-matrix. These results are based on a closed form solution of the Dyson equation combined with the Ward identity. Analytical properties of the solution are discussed. Further we describe the combinatorics of the Feynman diagrams for the Green’s function and the skeleton diagrams for the self-energy and vertex, using recurrence relations between the Taylor expansion coefficients of the self-energy. Asymptotically exact equations for the number of skeleton diagrams in the limit of large NN are derived. Finally, we consider possible realizations of a multicomponent Gaussian random potential in quantum transport via complex quantum dot experiments.

Robot visual navigation estimation and target localization based on neural network

Abstract The high computational cost, complex external environment, and limited computing resources of embedded system are some major problems in traditional autonomous robot navigation methods. To overcome these problems, a mobile robot path planning navigation system based on panoramic vision was proposed. This method first describes the structure and functions of the navigation system. It explains how to use the environment to explore and map in order to create a panoramic vision sensor. Finally, it elaborates on the breadth-first search based on regression neural network (RNN) method, the Voronoi skeleton diagram method, the algorithm principle, and how to navigate by the planning path implementation of practical strategies. The simulation results illustrate that the breadth-first search method and the Voronoi skeleton graph method based on panoramic view have a high speed. The accessibility of RNN planning algorithm can effectively solve the difficult problems such as high computing overhead, complex navigation environment, and limited computing resources. In the actual robot navigation experiment, the difference in real-time performance and optimality performance that exists between the two algorithms is reflected in the length and duration of the course taken by the robot. When applied to a variety of site environments, the breadth-first search method requires between 23.2 and 45.3% more time to calculate the planned path than the Voronoi skeleton graph method, despite the fact that the planned path length is between 20.7 and 35.9% shorter using the breadth-first search method. It serves as a guide for choosing the appropriate algorithm to implement in practical applications.

Design of Basketball Player Training Action Error Correction System Based on Convolutional Neural Network Algorithm

With the development of industry and the progress of science and technology, more and more new technology is gradually applied to the movement of error correction. This not only relieves workers of unneeded burdens by making their task more straightforward and error-free, but it also improves production efficiency. Deep neural networks are one of these new technologies that have exploded in popularity in recent years, with applications in a variety of industries. Of course, the application in image recognition must not be less, image recognition technology based on deep neural network has become more mature, and the error rate of recognition is now much lower than human vision recognition. So at present, some industrial detection is gradually from human vision detection to computer vision detection. This study discloses a basketball action error correction method based on deep learning image recognition, which includes the following steps: receiving each frame of basketball image captured from the fitness video, recording the corresponding time of each frame of fitness image, and preprocessing each frame of fitness image; the preprocessed basketball image was fed into the human joint recognition model, and the human joint recognition model calculated each human joint in the fitness image and output its position coordinates. According to the coordinate position of each joint orderly line, the human skeleton diagram is obtained; the human skeleton diagram is compared and assessed in accordance with standard fitness action, and the nonstandard basketball image is generated to realize basketball action repair. A basketball action error correction system based on deep learning picture identification is also disclosed in the invention. The system and method are capable of efficiently addressing the difficult challenge of comparing fitness movements with and without music rhythm.

Diagrammar of physical and fake particles and spectral optical theorem

We prove spectral optical identities in quantum field theories of physical particles (defined by the Feynman iϵ prescription) and purely virtual particles (defined by the fakeon prescription). The identities are derived by means of purely algebraic operations and hold for every (multi)threshold separately and for arbitrary frequencies. Their major significance is that they offer a deeper understanding on the problem of unitarity in quantum field theory. In particular, they apply to “skeleton” diagrams, before integrating on the space components of the loop momenta and the phase spaces. In turn, the skeleton diagrams obey a spectral optical theorem, which gives the usual optical theorem for amplitudes, once the integrals on the space components of the loop momenta and the phase spaces are restored. The fakeon prescription/projection is implemented by dropping the thresholds that involve fakeon frequencies. We give examples at one loop (bubble, triangle, box, pentagon and hexagon), two loops (triangle with “diagonal”, box with diagonal) and arbitrarily many loops. We also derive formulas for the loop integrals with fakeons and relate them to the known formulas for the loop integrals with physical particles.

Kubo estimation of the electrical conductivity for a hot relativistic fluid in the presence of a magnetic field

We have explored the multi-component structure of electrical conductivity of relativistic Fermionic and Bosonic fluid in presence of magnetic field by using Kubo approach. This is done by explicitly evaluating the thermo-magnetic vector current spectral functions using the real time formalism of finite temperature field theory and the Schwinger proper time formalism. In absence of magnetic field, the one-loop diagramatic representation of Kubo expression of any transport coefficients is exactly same with relaxation time approximation (RTA) based expression, but this equality does not hold for finite magnetic field picture due to lacking of proper implementation of quantum effect in latter approach. We have shown this discrepancy for particular transport coefficient - electrical conductivity, whose starting point in Kubo approach will be electromagnetic current-current correlator and its one-loop skeleton diagram carrying two scalar/Dirac propagators for scalar/Dirac fluid. Through a numerical comparison between RTA and Kubo expressions of conductivity components (parallel and perpendicular), we have attempted to interpret detail quantum field theoretical effect, contained by Kubo expression but not by RTA expression. In classical RTA expression we get magnetic field independent parallel conductivity due to zero Lorentz force but in field theoretical Kubo expression, it decreases and increases with the magnetic field for scalar and Dirac medium respectively due to Landau quantization effect. This parallel component of conductivity can be interpreted as zero momentum limit of quantum fluctuation with same Landau level internal lines. While for perpendicular component of conductivity, fluctuation with Landau level differences $\pm 1$ are noticed, which might be a new realization of transportation in field theoretical sector.

Cwebs beyond three loops in multiparton amplitudes

Correlators of Wilson-line operators in non-abelian gauge theories are known to exponentiate, and their logarithms can be organised in terms of collections of Feynman diagrams called webs. In [1] we introduced the concept of Cweb, or correlator web, which is a set of skeleton diagrams built with connected gluon correlators, and we computed the mixing matrices for all Cwebs connecting four or five Wilson lines at four loops. Here we complete the evaluation of four-loop mixing matrices, presenting the results for all Cwebs connecting two and three Wilson lines. We observe that the conjuctured column sum rule is obeyed by all the mixing matrices that appear at four-loops. We also show how low-dimensional mixing matrices can be uniquely determined from their known combinatorial properties, and provide some all-order results for selected classes of mixing matrices. Our results complete the required colour building blocks for the calculation of the soft anomalous dimension matrix at four-loop order.

Multi-filter dynamic graph convolutional networks for skeleton-based action recognition

Abstract Action recognition plays an important role in video understanding, and the dynamic changes of human bones provide important information for it. In order to solve the problem that the source point can only obtain the characteristics of adjacent nodes and the static structure of the skeleton diagram can not meet the adaptive requirements, this paper proposes an Inception structure and dynamic skeleton diagram based on the convolutional neural network, namely, the multi-filter dynamic graph convolutional neural network. The method can not only enable the source point to obtain the characteristics of distant nodes, but also can use the dynamic skeleton diagram structure to generate different body associations for different actions, which improves the adaptability and accuracy of the model and achieves better results.

Multiparton webs beyond three loops

Correlators of Wilson-line operators are fundamental ingredients for the study of the infrared properties of non-abelian gauge theories. In perturbation theory, they are known to exponentiate, and their logarithm can be organised in terms of collections of Feynman diagrams called webs. We study the classification of webs to high perturbative orders, proposing a set of tools to generate them recursively: in particular, we introduce the concept of Cweb, or correlator web, which is a set of skeleton diagrams built with connected gluon correlators, instead of individual Feynman diagrams. As an application, we enumerate all Cwebs entering the soft anomalous dimension matrix for multi-parton scattering amplitudes at four loops, and we compute the mixing matrices for all Cwebs connecting four or five Wilson lines at that loop order, verifying that they obey sum rules that were derived or conjectured in the literature. Our results provide the colour building blocks for the calculation of the soft anomalous dimension matrix at four-loop order.

Phonon-mediated superconductivity in strongly correlated electron systems: A Luttinger–Ward functional approach

We use a Luttinger–Ward functional approach to study the problem of phonon-mediated superconductivity in electron systems with strong electron–electron interactions (EEIs). Our derivation does not rely on an expansion in skeleton diagrams for the EEI and the resulting theory is therefore nonperturbative in the strength of the latter. We show that one of the building blocks of the theory is the irreducible six-leg vertex related to EEIs. Diagrammatically, this implies five contributions (one of the Fock and four of the Hartree type) to the electronic self-energy, which, to the best of our knowledge, have never been discussed in the literature. Our approach is applicable to (and in fact designed to tackle superconductivity in) strongly correlated electron systems described by generic lattice models, as long as the glue for electron pairing is provided by phonons.

A distinct matrix representation of the planar kinematic chains and isomorphism recognition

Structural synthesis of kinematic chains has been an indispensable area of the mechanism-design problem. The duplication may occur while developing kinematic chains. Therefore, an isomorphic test is required to eliminate duplication. For this purpose, the numbers of methods are proposed during recent years. However, most of the methods are complex and difficult to understand, and fulfil the only primary condition, but not the secondary conditions for isomorphism detection. In the present work, a new method is introduced to detect isomorphism in planar kinematic chains (KCs) fulfilling both primary and secondary conditions. First, KC’s are topologically transformed into skeleton diagrams, and then skeleton matrices [S] and identification strings [IS] are formulated consequently. In order to detect isomorphism, the IS is considered as an invariant string of a KC which in turn, enables the detection of isomorphism between the KCs. The proposed method accurately recognizes isomorphism up to 12 links KCs with no counter examples found in the literature. Three examples with one degree of freedom having 10 links 12 joints, 10 links 13 joints and 12 links three degree of freedom systems are introduced to reveal the reliability and strength of the proposed method.

Method of application of shells of the navigation signals equipped with the device of relaying for determination of installations for firing

In article conditions under which it is impossible to apply the existing methods and means of determination of installations for firing at the unobservable targets at the big distances of firing are analyzed and the new method of determination of installations for firing which are determined by results of adjustment fire of the target by the shells equipped with the device of relaying of navigation signals of navigation satellite systems is offered. The specified method provides creation of the determination system of shell coordinates which consists of the device of navigation relaying signals and the land measuring instrument of the base station. In the device of relaying of navigation signals the equipment of relaying of navigation signals accepted from navigation space satellites and pilot - signals is placed, it is offered to be developed in the form of the detonator which is twisted in the front part of the shell. The land measuring instrument of the base station contains the receiver of the relayed signals, processing units of the relayed signals and direct signals of navigation space satellites, the personal electronic computer with the corresponding software, the protection module from “intellectual noises and the protection system against radio-electronic suppression. Skeleton diagrams of the device of relaying of navigation signals and the land measuring instrument of the base station are presented in article with the description of the principles of their work. Errors which occur during relaying navigation signals are considered, their maximum values are defined, their influence on the accuracy of determining the coordinates of the place,where the shell can fall is analyzed by the land measuring instrument of the base station. Also the method of determination of installations for firing at the unobservable targets by adjustment fire is described by the ammunition equipped with the device of relaying of navigation signals of navigation satellite systems. Comparative analysis of accuracy of determination of installations for firing of the data received by the method of complete preparation and by the method of calculation obtained during adjustment fire of the purpose by the shells equipped with the device of relaying of navigation signals is carried out; benefits and shortcomings are analyzed. Possible methods of application of the shells equipped with the device of relaying of navigation signals are offered.

From in-Medium Color Forces to Transport Properties of QGP

A thermodynamic quantum many-body T-matrix approach is employed to study the spectral and transport properties of the quark-gluon plasma at moderate temperatures where nonperturbative effects are essential. For the partonic two-body interaction we utilize a QCD-inspired Hamiltonian whose color forces are motivated by the heavy-quark (HQ) limit including remnants of the confining force, and augmented by relativistic corrections. We solve the in-medium parton propagators and T-matrices selfconsistently and resum the skeleton diagrams for the equation of state (EoS) to all orders thereby accounting for the dynamical formation of two-body bound states. Two types solutions for the in-medium potential are found in when fitting to lattice-QCD data for the EoS, HQ free energy and quarkonium correlators: a weakly-coupled scenario (WCS) with a (real part of the) potential close to the free energy, resulting in moderately broadened spectral functions and weak bound states near Tc, and a strongly-coupled scenario (SCS), with a much stronger potential which produces large imaginary parts (“melting” the parton spectral functions) and generates strong bound states near Tc. We calculate pertinent transport coefficients (specific shear viscosity and HQ diffusion coefficient) and argue that their constraints from heavy-ion phenomenology unambiguously favor the strongly-coupled scenario.

Gesture recognition based on skeletonization algorithm and CNN with ASL database

In the field of human-computer interaction, vision-based gesture recognition methods are widely studied. However, its recognition effect depends to a large extent on the performance of the recognition algorithm. The skeletonization algorithm and convolutional neural network (CNN) for the recognition algorithm reduce the impact of shooting angle and environment on recognition effect, and improve the accuracy of gesture recognition in complex environments. According to the influence of the shooting angle on the same gesture recognition, the skeletonization algorithm is optimized based on the layer-by-layer stripping concept, so that the key node information in the hand skeleton diagram is extracted. The gesture direction is determined by the spatial coordinate axis of the hand. Based on this, gesture segmentation is implemented to overcome the influence of the environment on the recognition effect. In order to further improve the accuracy of gesture recognition, the ASK gesture database is used to train the convolutional neural network model. The experimental results show that compared with SVM method, dictionary learning + sparse representation, CNN method and other methods, the recognition rate reaches 96.01%.

T -matrix approach to quark-gluon plasma

A selfconsistent thermodynamic $T$-matrix approach is deployed to study the microscopic properties of the quark-gluon plasma (QGP), encompassing both light- and heavy-parton degrees of freedom in a unified framework. The starting point is a relativistic effective Hamiltonian with a universal color force. The input in-medium potential is quantitatively constrained by computing the heavy-quark (HQ) free energy from the static $T$-matrix and fitting it to pertinent lattice-QCD (lQCD) data. The corresponding $T$-matrix is then applied to compute the equation of state (EoS) of the QGP in a two-particle irreducible formalism including the full off-shell properties of the selfconsistent single-parton spectral functions and their two-body interaction. In particular, the skeleton diagram functional is fully resummed to account for emerging bound and scattering states as the critical temperature is approached from above. We find that the solution satisfying three sets of lQCD data (EoS, HQ free energy and quarkonium correlator ratios) is not unique. As limiting cases we discuss a weakly-coupled solution (WCS) which features color-potentials close to the free energy, relatively sharp quasiparticle spectral functions and weak hadronic resonances near $T_{\rm c}$, and a strongly-coupled solution (SCS) with a strong color potential (much larger than the free energy) resulting in broad non-quasiparticle parton spectral functions and strong hadronic resonance states which dominate the EoS when approaching $T_{\rm c}$.

Higher-order Fermi-liquid corrections for an Anderson impurity away from half filling : Equilibrium properties

We study the low-energy behavior of the vertex function of a single Anderson impurity away from half filling for finite magnetic fields, using the Ward identities with careful consideration of the antisymmetry and analytic properties. The asymptotic form of the vertex function ${\mathrm{\ensuremath{\Gamma}}}_{\ensuremath{\sigma}{\ensuremath{\sigma}}^{\ensuremath{'}};{\ensuremath{\sigma}}^{\ensuremath{'}}\ensuremath{\sigma}}^{}(i\ensuremath{\omega},i{\ensuremath{\omega}}^{\ensuremath{'}};i{\ensuremath{\omega}}^{\ensuremath{'}},i\ensuremath{\omega})$ is determined up to terms of linear order with respect to the two frequencies $\ensuremath{\omega}$ and ${\ensuremath{\omega}}^{\ensuremath{'}}$, as well as the ${\ensuremath{\omega}}^{2}$ contribution for antiparallel spins ${\ensuremath{\sigma}}^{\ensuremath{'}}\ensuremath{\ne}\ensuremath{\sigma}$ at ${\ensuremath{\omega}}^{\ensuremath{'}}=0$. From these results, we also obtain a series of the Fermi-liquid relations beyond those of Yamada-Yosida [Prog. Theor. Phys. 54, 316 (1975)]. The ${\ensuremath{\omega}}^{2}$ real part of the self-energy ${\mathrm{\ensuremath{\Sigma}}}_{\ensuremath{\sigma}}^{}(i\ensuremath{\omega})$ is shown to be expressed in terms of the double derivative ${\ensuremath{\partial}}^{2}{\mathrm{\ensuremath{\Sigma}}}_{\ensuremath{\sigma}}^{}(0)/\ensuremath{\partial}{\ensuremath{\epsilon}}_{d\ensuremath{\sigma}}^{2}$ with respect to the impurity energy level ${\ensuremath{\epsilon}}_{d\ensuremath{\sigma}}^{}$, and agrees with the formula obtained recently by Filippone, Moca, von Delft, and Mora (FMvDM) in the Nozi\`eres phenomenological Fermi-liquid theory [Phys. Rev. B 95, 165404 (2017)]. We also calculate the ${T}^{2}$ correction of the self-energy and find that the real part can be expressed in terms of the three-body correlation function $\ensuremath{\partial}{\ensuremath{\chi}}_{\ensuremath{\uparrow}\ensuremath{\downarrow}}/\ensuremath{\partial}{\ensuremath{\epsilon}}_{d,\ensuremath{-}\ensuremath{\sigma}}^{}$, where ${\ensuremath{\chi}}_{\ensuremath{\uparrow}\ensuremath{\downarrow}}$ is the static susceptibility between antiparallel spins. We also provide an alternative derivation of the asymptotic form of the vertex function. Specifically, we calculate the skeleton diagrams for the vertex function ${\mathrm{\ensuremath{\Gamma}}}_{\ensuremath{\sigma}\ensuremath{\sigma};\ensuremath{\sigma}\ensuremath{\sigma}}^{}(i\ensuremath{\omega},0;0,i\ensuremath{\omega})$ for parallel spins up to order ${U}^{4}$ in the Coulomb repulsion $U$. It directly clarifies the fact that the analytic components of order $\ensuremath{\omega}$ vanish as a result of the cancellation of four related Feynman diagrams, which are related to each other through the antisymmetry operation.

Renormalized asymptotic enumeration of Feynman diagrams

A method to obtain all-order asymptotic results for the coefficients of perturbative expansions in zero-dimensional quantum field is described. The focus is on the enumeration of the number of skeleton or primitive diagrams of a certain QFT and its asymptotics. The procedure heavily applies techniques from singularity analysis. To utilize singularity analysis, a representation of the zero-dimensional path integral as a generalized hyperelliptic curve is deduced. As applications the full asymptotic expansions of the number of disconnected, connected, 1PI and skeleton Feynman diagrams in various theories are given.

INCREASE OF EFFICIENCY OF SUPPRESSION OF THE ACTIVE NOISE JAMMING IN RADAR INTERCEPTION OF AIR TARGETS IN THE REVIEW MODE

The modified algorithm of the adaptive compensating of the active noise jamming, based on usage of the recurrence estimation of inverse covariance matrix of jamming in the course of an self-tuning is considered. The matrix estimation is formed by a method of a serial regression (SRM), a consequence application of a lemma about inversing of a matrix to differential – to the difference equation for a rounded estimation of direct covariance matrix of jamming (CMJ). The single estimation of straight line CMJ is formed as result dyad products of the instant vectors of noises in handling channels. In partial channels the adaptive transversal filters with the self-tuning on value of a signal of an aggregate error are implemented.In article skeleton diagrams of devices of the compensating implemented by various methods are resulted. Mathematical modeling of operation of the algorithms, implemented by a method of the least squares (criterion of a minimum RMS error) and a method of a serial regression is performed.Results of mathematical modeling of operation of the device of compensating of active noises jamming in the conditions of the active radio-electronic counteraction at multipath propagation of signals both non-identical amplitude and phase characteristics of channels of handling are resulted. Optimal values of technical parameters of devices of compensating of the active noises jamming providing obtaining of demanded values of coefficient of suppression are given. The comparative analysis of indexes of efficiency of classical and offered algorithms of compensating is made. Advantage of algorithm of compensating of the active noises jamming, using the recurrence estimation of a inverse covariance matrix of jamming is shown.The algorithm of functioning on the basis of SRM allows to lower essentially requirements to specialized VLSI (FPGA) at implementation is hardware – program complexes for preprocessing of the radar, radio communication and radio – navigation information in the conditions of influence of the active noises jamming in the presence of effects of multipath propagation of signals, in the presence of delay of signals on an antenna system aperture, and also at unremovable technological dispersion amplitude and phase characteristics of the microwave of channels of handling.

Finding Hama: On the Identification of a Forgotten Queen Buried in the Nimrud Tombs

Finding Hama: On the Identification of a Forgotten Queen Buried in the Nimrud Tombs

T-Matrix Approach to Strongly Coupled QGP

Based on a thermodynamic T-matrix approach we extract the potential V between two static charges in the quark-gluon plasma (QGP) from ts to the pertinent lattice-QCD free energy. With suitable relativistic corrections we utilize this new potential to compute heavy-quark transport coefficients and compare the results to previous calculations using either F or U as potential. We then discuss a generalization of the T-matrix re-summation to a “matrix log” re-summation of t-channel diagrams for the grand partition function of the QGP in the Luttinger-Ward skeleton diagram formalism. With V as a non-perturbative driving kernel in the light-parton sector, we obtain the QGP equation of state from ts to lattice-QCD data. The resulting light-parton spectral functions are characterized by large thermal widths at small momenta, indicating the dissolution of quasi-particles in a strongly coupled QGP.

Parametric synthesis of assembly device for fitting rubber sealing ring into the inner groove of the basic item

On the basis of the block diagram of the assembly device technological system a group of morphological matrices of various hierarchy levels may be built. The analysis of the engineering system “ the assembly device for assembly Seal of connections ” is manufactured. The structure of the engineering system and e ё of units at different hierarchical levels is defined, the links between subsystems are detected. On the basis of the skeleton diagram of the assembly device the group of morphological matrixes, different levels of hierarchy is constructed. The synthesis of variants of structure of the assembly device is manufactured.