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Efficient analysis of electromagnetic scattering from three-dimensional, perfect electrically conducting, multiscale structures in a half space is conducted in this paper. The half-space dyadic Green's function is adopted as the kernel of the electric field integral equation so that the unknowns are only associated with the surface of the scatterers. A recently developed Calderon preconditioner is...
This paper proposes an control strategy for the voltage control of an inner current-controlled distributed energy resource units (DERs) in an islanded microgrid to provide overcurrent protection under unbalanced faults. During the unbalanced voltage sag, even though the inner current-controlled limit the current magnitude, the peak phase current may still exceed the limit value. The control strategy...
In this paper, an integral equation domain decomposition method based on hybrid solvers (HS-DDM) are developed for modeling of electromagnetic radiation problems. Based on the philosophy of ‘divided and conquer’, the IE-DDM divides the original multi-scale problem into many closed non-overlapping sub-domains. The Robin transmission conditions ensure the continuity of the currents across adjacent sub-domains...
To solve the scattering from multiple bodies of revolution (BoRs), a fast iterative solver is proposed in this paper. By dividing the original multiple BoRs problem into single BoR problems, the present method can achieve a fast solution by the method of moment for single BoR problem and an efficient strategy for calculating interactions between different BoRs. Due to the rotational symmetry of single...
Lattice codes can achieve the capacity of additive white Gaussian noise channel with and without power construction. It is well known that lattice codes can provide a classical information theoretic way to obtain achievable rate and performance gains for point-to-point Gaussian channels. The coding scheme based on lattice codes can be used as building blocks for practical applications, such as point-to-point...
Microsoft Office is the most popular office software. Office document security is mainly carried out through encryption by the software encryption function. But as the new decoding method is put forward and the computer speed is accelerated rapidly, the document security has been questioned. This paper analyzed the whole process of Office 2013 file encryption/decryption, designed a contrast experiment...
Assembly processing and state of micro-strip boards, such as splicing gap and soldering voiding, have significant influence on microwave transmission in microwave modules. Based on 3D electromagnetic simulated analysis, the influences of splicing gap and soldering voiding of micro-strip boards on properties of microwave transmission in S, X and Ku bands, such as insertion loss and voltage standing...
A simple but efficient finite-difference time-domain (FDTD) method integrated with auxiliary differential equation (ADE) for modelling periodic graphene-based structures is proposed. Based on the integral form of Ampere's circuital law, the derived equations are simpler than those of subcell method proposed by the others. Numerical experiments are carried out to validate our method in comparison with...
This paper proposes the design of a novel beam reconfigurable antenna operating at 500GHz. Such antenna is based on single-layer-graphene patches with tunable electrical conductivity. Three groups of graphene patches play a key role for achieving directivity such as for the Yagi-Uda antenna. The conductivity of each graphene patch can be dynamically controlled by the DC biasing voltage. Numerical...
This experimental study reported electrical properties of linear low density polyethylene (LLDPE)/SiO2 nanocomposites prepared by melt blending methods. The effects of surface modified SiO2 nanoparticles on the microstructure, space charge distribution and thermally stimulated current were investigated. The addition of surface modified nanoparticles increases the amount of spherulites and decreases...
A ray-tracing based FDTD Meshing algorithm, combined with SIMD technique is propose for FDTD simulation of aircraft platform in this paper. During the implementation of such technique, the original ray-tracing formulation is changed into the vector operation form. The proposed algorithm is then applied for constructing the FDTD mesh for an aircraft model. It is shown that such new SIMD can achieve...
Electromagnetic (EM) scattering from thin coating on conducting objects is a classic topic that arises in many practical application. The complexity of absorbing material application demands for sophisticated and flexible numerical methods. It can be argued that these requirements are even more critical when the cost of building and measuring a real coated object is great. Usually, impedance boundary...
The low surface DC flashover voltage for the cone-type insulator has restrained the industrial application of high voltage apparatus especially for gas-insulated substation and gas-insulated transmission lines. However, the surface charge under DC, which produces uniform electric fields resulting in surface flashover under low direct voltage, are still not investigated clearly. In this paper, the...
Electromagnetic local density of states (ELDOS) counts the number of electromagnetic modes at a spatial point where a particle (atom, molecule, and quantum dot) spontaneously emits electromagnetic waves. ELDOS can be interpreted as a density of vacuum fluctuations of electromagnetic fields. Moreover, ELDOS is essential to control spontaneous decay rate (SDR) of particles; and thus plays a critical...
Electromagnetic scattering by three-dimensional complex perfect electrically conducting (PEC) objects buried under ground is investigated in this paper. The air-soil composite is approximated by a half-space model, where the half-space Green's function is adopted in the formulation of the electric field integral equation (EFIE). The simulation efficiency is improved from the following two aspects:...
Fast direct techniques for solving integral equations are rapidly gaining traction as viable alternatives to iterative schemes. Indeed, iterative methods converge slowly when applied to (intrinsically) ill-conditioned problem and grind to a halt when applied to problems involving many right-hand sides. Our group recently developed direct electric and combined field integral equation solvers that use...
One novel graphene-based high-impedance surface (HIS) is proposed in this paper. It utilizes the metal patches to reduce the loss effect, and the graphene patches to alter the reflection phase of the HIS. By using such HIS, a 2-D THz Fabry-Perot antenna is designed and investigated. It is shown that by adjusting the graphene conductivity, both the resonance and beam direction of 2-D THz Fabry-Perot...
A simple and efficient auxiliary-difference-equation finite-difference time-domain (ADE-FDTD) method for modelling graphene-based structures is presented in this paper. By considering the graphene sheet as a polarization current source characterized by an auxiliary equation (AE), the proposed method can be easily adopted to simulate graphene-based structures biased by electrostatic or magnetostatic...
Producing educational serious games can be costly and time-consuming. The Service-Oriented Architecture (SOA) approach of software development can offer a solution to reduce costs and foment serious games development. In this work, we apply a model called Activity Theory-based Model of Serious Games (ATMSG) for identifying existing relevant components that can be reused for different educational serious...
Image registration for stack-based HDR photography is challenging. If not properly accounted for, camera motion and scene changes result in artifacts in the composite image. Unfortunately, existing methods to address this problem are either accurate, but too slow for mobile devices, or fast, but prone to failing. We propose a method that fills this void: our approach is extremely fast—under 700ms...
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