Efficient Calculation Procedure Research Articles

Efficient Arbitrated Quantum Digital Signature with Multi‐Receiver Verification

AbstractQuantum digital signature is used to authenticate the identity of the signer with information theoretical security while providing non‐forgery and non‐repudiation services. In traditional multi‐receiver quantum digital signature schemes without an arbitrator, the transferability of one‐to‐one signature is always required to achieve unforgeability, with complicated implementation and heavy key consumption. In this article, an arbitrated quantum digital signature scheme is proposed, in which the signature can be verified by multiple receivers simultaneously, and meanwhile, the transferability of the signature is still kept. This scheme can be simplified performed to various quantum secure networks, due to the proposed efficient signature calculation procedure with low secure key consumption and low computation complexity, by employing one‐time universal hashing algorithm and a one‐time pad encryption scheme. The evaluation results show that this scheme uses at least two orders of magnitude less key than existing signature schemes with transferability when signing files of the same length with the same number of receivers and security parameter settings.

Implementation of a coupled FEM-SBFEM for soil-structure interaction analysis of large-scale 3D base-isolated nuclear structures

Accurately simulating the radiation damping of an infinite domain is a crucial issue for reasonably and effectively evaluating the isolation effect of three-dimensional (3D) base-isolated nuclear structures considering soil-structure interaction (SSI). The scaled boundary finite element method (SBFEM) has excellent advantages that enable it to precisely fulfil the radiation conditions. In this study, the finite element method (FEM) and SBFEM were combined to develop a coupled FEM-SBFEM technology. The structure and finite domain were discretized using FEM, and the infinite soil was realised using SBFEM. A complete and efficient calculation procedure for SSI analysis was developed based on the coupled FEM-SBFEM, improving the calculation efficiency through parallel programming. The accuracy of the developed procedure was verified using a numerical example. Furthermore, the dynamic response of a large-scale refined 3D base-isolated reactor building considering SSI was analysed using the proposed method. The results demonstrate that the 3D base isolation technology has excellent isolation performance. Additionally, we compared the response results of the proposed coupled FEM-SBFEM and direct method. The proposed procedure has broad engineering applicability and can be used for seismic SSI analysis of large-scale nuclear structures while maintaining high computational accuracy and stability.

A Graph Entropy Measure From Urelement to Higher-Order Graphlets for Network Analysis

Graph entropy measures have recently gained wide attention for identifying and discriminating various networks in biology, society, transportation, etc. However, existing methods cannot sufficiently explore the structural contents by merely considering the elementary invariants of a graph, ignoring the underlying patterns in higher-order features. In this paper, we propose a general <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">entropy-based graph representation framework</i> ( <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Greet</small> ) based on four pertinent properties of graphlet topology from urelement to higher-order statistics. Specifically, we introduce an unbiased graphlet estimation strategy for obtaining both urelement and higher-order statistics. Additionally, we define a novel family of information functions based on hierarchical topological features to compute the graph entropy, then construct a graph information entropy (GIE) vector using the obtained local and global structural statistics to facilitate downstream tasks. Furthermore, there are some advantages that our <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Greet</small> exhibits over other methods: (a) high accuracy with <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$&lt; 1\%$</tex-math></inline-formula> relative error; (b) scalable for even larger vertex graphlets; (c) efficient calculation procedure with feasible speedup. Extensive experiments show that <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Greet</small> exhibits superior performance on graph classification and clustering tasks, achieving remarkable improvements compared to several baselines. Altogether these findings pave the way for a wide range of applications of graphlet-based entropy as a complexity metric in graph analysis.

Efficient calculation of highly focused electromagnetic Schell-model beams.

The calculation of the propagation of partially coherent and partially polarized optical beams involves using 4D Fourier Transforms. This poses a major drawback, taking into account memory and computational capabilities of nowadays computers. In this paper we propose an efficient calculation procedure for retrieving the irradiance of electromagnetic Schell-model highly focused beams. We take advantage of the separability of such beams to compute the cross-spectral density matrix by using only 2D Fourier Transforms. In particular, the number of operations depends only on the number of pixels of the input beam, independently on the coherence properties. To provide more insight, we analyze the behavior of a beam without a known analytical solution. Finally, the numerical complexity and computation time is analyzed and compared with some other algorithms.

Postflutter Analysis of Bridge Decks Using Aerodynamic-Describing Functions

An aerodynamic describing function (ADF)-based model for simulating the nonlinear self-excited forces on bridge decks is developed, where the ADFs can be conveniently identified using the experimentally or numerically obtained free or forced vibration data. An efficient calculation procedure based on the ADFs is accordingly established to predict the nonlinear flutter state and/or postflutter limit cycle oscillations (LCOs). Two numerical examples are utilized to demonstrate the simulation accuracy and efficiency of nonlinear bridge flutter with the proposed ADF-based model. The capabilities of the ADF-based model in capturing typical features of nonlinear postflutter vibration such as LCO and a hysteresis phenomenon are demonstrated. A nondimensional postflutter index is designed to quantitatively assess the postflutter performance of bridge decks. Finally, the effects of structural dynamics and aerodynamic properties (e.g., structural damping ratios, natural frequencies, and aerodynamic derivatives) on the postflutter behavior of a bridge deck are examined in terms of the wind speed extension after the critical state with acceptable postcritical vibrations and the proposed postflutter index.

3D FEM analysis of the effect of buried phononic crystal barriers on vibration mitigation

Vibration induced by vehicles is a significant problem in large cities causing a major impact on human activities, comfort and health. Besides well-known strategies to mitigate vibrations and their effects, innovative methods are being devised using novel physical concepts. Those are already well-developed for the case of acoustic barriers, for example made of periodically arranged elements (known as “sonic” or “phononic” crystals), however the shielding of structures from the effect of vibrations is still in an earlier development stage. In this context, this paper describes several studies on the concept of a periodic buried structure, made of stiff inclusions (e.g. concrete), deployed with a geometrical arrangement that may allow efficient filtering of dominant vibration frequencies. A 3D finite element model is used formulated in time domain to perform a detailed numerical assessment of the effectiveness of the proposed shielding device. Simulations are performed using a time-marching algorithm to allow an efficient calculation procedure. Results are promising, clearly revealing the existence of band gaps of large attenuation, although limitations related to the existence of guided waves travelling along the inclusions are also identified.

Load service restoration in active distribution network based on stochastic approach

A new stochastic framework is proposed for distribution system restoration (DSR) problem. In this framework, dynamic programming (DP) is used to solve DSR problem for a distribution system that accommodates various technologies of distributed generation units and storage systems. Time and sequence of distribution feeders which should be energised after a blackout are chosen as stages of DP algorithm. In addition, uncertainties associated with the power received from transmission network in the period of system restoration are modelled as some probabilistic scenarios. The complexity of attained optimisation problem is reduced using some state reduction techniques. These techniques enable DP algorithm to reach near-optimal solution as well as computationally efficient calculation procedure. The proposed restoration framework is applied on a real-world test system and the results prove its effectiveness and practicality.

Queuing loss models with more alternative heterogeneous groups

SummaryThis paper considers queuing model with 2 Poisson traffics offered to the primary group, where the rejected demands of one of them are overflowed to the alternative groups in sequence and leave the system without being served when all channels are busy. Here, serving intensity from primary group is changed and gets various values in alternative groups. Generating function technique is used for the analytical solution of steady‐state equations system. Common solution obtained for the state probabilities permits efficient procedure for model parameters calculation. Next, explicit solutions in the case with secondary and tertiary groups are derived. Moreover, obtained solutions for binomial moments are of significant importance for treating more complex models. Some numerical results are also presented through illustrative examples justifying the need to dedicate special attention to the cases where phenomenon of heterogeneous alternative channels or groups is remarked. In addition, as an example, explicit solution for the model with primary group and 3 heterogeneous alternate channels is obtained. This leads to the comparative support when solving 4 channels system with losses and renewal arrivals. These solutions represent a prospective tool applicable in different serving situations, particularly considering traditional and next generation communications networks.

Development of an efficient calculation procedure for elastic forces in the ANCF beam element by using a constrained formulation

The absolute nodal coordinate formulation (ANCF) is often used for the large rotation and deformation analysis. In the ANCF, absolute nodal coordinates and global slopes are utilized as the element nodal coordinates. Accordingly, it gives a constant and symmetric mass matrix. On the other hand, elastic forces are generally expressed by highly nonlinear terms. Therefore, one of the important topics in the implementation of the ANCF is to derive mathematical descriptions of the elastic forces which can be calculated efficiently. This study focuses on development of efficient calculation procedures for the ANCF beam element under the assumption of the Euler–Bernoulli beam theory. In particular, we focus on the fact that the elastic forces can be described in simpler forms with the element coordinates. It implies that appropriate choices of the coordinate systems for the inertia and the elastic forces could contribute to the development of efficient calculation procedures. In the present formulation, the strain and the kinetic energies are expressed as functions of the element and the global coordinates, respectively. Then algebraic constraints regarding the relations between the global and the element coordinate systems are introduced by means of the Lagrange method of undetermined multipliers. These constraints are used for eliminating the redundant degrees of freedom from a standpoint of consistency in the formulation. Therefore, this method can be categorized as an augmented formulation technique. The equations of motions of this constrained system are derived by the method for constrained Hamiltonian system, namely Dirac’s method with the Poisson bracket formalism. In order to evaluate the proposed method, it is applied to the large deformation problem in the plane case. The equivalence of the previous approach and the proposed method is discussed by a comparison of the two. In addition, its computational performance is investigated.

Verification of deflection according to Eurocode 2

Code provisions for a simplified check of the long‐term deflection of concrete structures are generally developed for predefined values of the relevant input parameters. Deflection calculation may be of interest to account for different design situations. EN 1992‐1‐1 advocates the integration of curvatures calculated using the effective modulus of concrete. This paper presents an efficient procedure for calculation of the long‐term deflection due to a sustained load. A nondimensional analysis of the mean curvature is applied to evaluate the deflection. The deflection is calculated using a set of algebraic expressions. The result is close to the value obtained by the numerical integration of curvatures. The values of relevant parameters in the expressions may be selected within the common range for the design of engineering structures. The efficiency of the deflection prediction based on the integration of curvatures is tested on the available experimental data. In the first approach, the measured material properties are used. In the second approach, the required values are derived from EN 1992‐1‐1 expressions to predict the material properties.

Evaluation of Vehicle Bottom for the Placement of HF-VHF Antennas

The bottom side of a vehicle is assessed for mounting HF-VHF antenna systems in terms of omni-directionality, efficiency and propagation loss. Accurate and numerically efficient procedure for calculation of propagation loss associated with sources electrically close to real grounds is proposed and carefully validated. It is shown that even though bottom sources cannot compete with conventionally mounted antennas in terms of far field omni-directionality and efficiency, in the near field region propagation loss margins are comparable for distances shorter than 10 m and frequencies from 20 to 100 MHz. The result points to the frequency range where antennas can be concealed at the bottom side and still used for emerging short distance applications.

Temperature Integration: An efficient procedure for calculation of free energy differences

We propose a method, Temperature Integration, which allows an efficient calculation of free energy differences between two systems of interest, with the same degrees of freedom, which may have rough energy landscapes. The method is based on calculating, for each single system, the difference between the values of lnZ at two temperatures, using a Parallel Tempering procedure. If our two systems of interest have the same phase space volume, they have the same values of lnZ at high-T, and we can obtain the free energy difference between them, using the two single-system calculations described above. If the phase space volume of a system is known, our method can be used to calculate its absolute (versus relative) free energy as well. We apply our method and demonstrate its efficiency on a “toy model” of hard rods on a 1-dimensional ring.

Accurate evaluation of the angular-dependent direct correlation function of water

The direct correlation function (DCF) plays a pivotal role in addressing the thermodynamic properties with non-mean-field statistical theories of liquid state. This work provides an accurate yet efficient calculation procedure for evaluating the angular-dependent DCF of bulk SPC∕E water. The DCF here represented in a discrete angles basis is computed with two typical steps: the first step involves solving the molecular Ornstein-Zernike equation with the input of total correlation function extracted from simulation; the resultant DCF is then polished in second step at small wavelength for all orientations in order to match correct thermodynamic properties. This function is also discussed in terms of its rotational invariant components. In particular, we show that the component c112(r) that accounts for dipolar symmetry reaches already its long-range asymptotic behavior at a short distance of 4 Å. With the knowledge of DCF, the angular-dependent bridge function of bulk water is thereafter computed and discussed in comparison with referenced hard-sphere bridge functions. We conclude that, even though such hard-sphere bridge functions may be relevant to improve the calculation of Helmholtz free energies in integral equations or density functional theory, they are doomed to fail at a structural level.

First-principles transport calculation method based on real-space finite-difference nonequilibrium Green's function scheme

We demonstrate an efficient nonequilibrium Green's function transport calculation procedure based on the real-space finite-difference method. The direct inversion of matrices for obtaining the self-energy terms of electrodes is computationally demanding in the real-space method because the matrix dimension corresponds to the number of grid points in the unit cell of electrodes, which is much larger than that of sites in the tight-binding approach. The procedure using the ratio matrices of the overbridging boundary-matching technique [Y. Fujimoto and K. Hirose, Phys. Rev. B 67, 195315 (2003)], which is related to the wave functions of a couple of grid planes in the matching regions, greatly reduces the computational effort to calculate self-energy terms without losing mathematical strictness. In addition, the present procedure saves computational time to obtain the Green's function of the semi-infinite system required in the Landauer-B\"uttiker formula. Moreover, the compact expression to relate Green's functions and scattering wave functions, which provide a real-space picture of the scattering process, is introduced. An example of the calculated results is given for the transport property of the BN ring connected to (9,0) carbon nanotubes. The wave-function matching at the interface reveals that the rotational symmetry of wave functions with respect to the tube axis plays an important role in electron transport. Since the states coming from and going to electrodes show threefold rotational symmetry, the states in the vicinity of the Fermi level, the wave function of which exhibits fivefold symmetry, do not contribute to the electron transport through the BN ring.

Quasicrystals as alloys with short-range order

The electronic structure of quasiperiodic lattices is studied. An alloy theory, including short-range order effects, is used to approximate Fibonacci and Thue–Morse lattices. Short-range order is treated by embedding small clusters in an alloy that itself incorporates a two-site approximation, and the probabilities of these clusters are used to construct an efficient procedure for the calculation of electronic properties. This approach allows easy identification of the contributions of particular clusters to the electronic density of states. As the short-range order is increased via the number of clusters, the density of states can be clearly seen to transition from that of an alloy to that of a quasicrystal. It is shown that the techniques may be applied to other lattices defined by substitution rules.

Numerical solution of some two-parameter eigenvalue problems

We consider an iteration algorithm for determining the eigenvalues of an algebraic two-parameter spectral problem with the use of Newton’s method and a new efficient numerical procedure for calculation of the derivative of a determinant. Numerical examples are given.

Bilateral analog of the Newton method for determination of eigenvalues of nonlinear spectral problems

The iterative algorithm for determination of bilateral (alternating) approximations to the eigenvalues of nonlinear spectral problems that uses a bilateral analog of the Newton method and a new efficient numerical procedure for calculation of the Newton correction and its derivative is proposed.

Calculation of sound propagation in three-dimensional field with constant cross section by Duhamel's efficient method using transient solutions obtained by finite-difference time-domain method

In this paper, a method of calculating transient responses in a three-dimensional (3-D) sound field with constant geometry along the longitudinal direction is described. In the presented method, two-dimensional (2-D) solutions obtained from the finite-difference time-domain method are applied to the efficient calculation procedure to transform the 2-D solution into the 3-D solution proposed by Duhamel. In order to confirm the validity of the presented calculation method, the insertion loss of two types of barriers is analyzed and the calculation results are compared with experimental results obtained from a scale-model experiment.

Efficient procedure for capacitance matrix calculation of multilayer VLSI interconnects using quasi-static analysis and Fourier series

Efficient procedure for capacitance matrix calculation of multilayer VLSI interconnects using quasi-static analysis and Fourier series

Application of the cause–consequence diagram method to static systems

Abstract In the last 30 years, various mathematical models have been used to identify the effect of component failures on the performance of a system. The most frequently used technique for system reliability assessment is Fault Tree Analysis (FTA) and a large proportion of its popularity can be attributed to the fact that it provides a very good documentation of the way that the system failure logic was developed. Exact quantification of the fault tree, however, can be problematic for very large systems and in such situations, approximations can be used. Alternatively, an exact result can be obtained via the conversion of the fault tree into a binary decision diagram (BDD). The BDD, however, loses all failure logic documentation during the conversion process. This paper outlines the use of the cause–consequence diagram method as a tool for system risk and reliability analysis. As with the FTA method, the cause–consequence diagram documents the failure logic of the system. In addition to this the cause–consequence diagram produces the exact failure probability in a very efficient calculation procedure. The cause–consequence diagram technique has been applied to a static system and shown to yield the same result as those produced by the solution of the equivalent fault tree and BDD. On the basis of this general rules have been devised for the correct construction of the cause–consequence diagram given a static system. The use of the cause–consequence method in this manner has significant implications in terms of efficiency of the reliability analysis and can be shown to have benefits for static systems.