Moments Formulation Research Articles

Pengaruh Pembelajaran Pendidikan Agama Islam Terhadap Perilaku Siswa di SMK Kesehatan Samarinda

Islamic teaching is a physical and spiritual guidance based on the holy Qur’an towards students in order to build a muslim personality completely. To have the good attitudes, students are expected to pay attention to the religion based learning as the control in the student’s life. Generally the aim of Islamic teaching is to build students who are faithful and devout to Allah SWT and have good characters. The function of Islamic teaching is to internalize faith and piety to Allah SWT and habituate students to implement the good characters both in family and school. Population in this research was all students of SMK Kesehatan Samarinda consisting of 426 students in the academic year of 2017/2018 with purposive sampling technique. Data collection techniques were questionnaires, observation and interviews. Data analysis technique used product moment formulation. The analysis shows that the two variables of the test by using Product Moment Correlation result in r calculation of 0,676 which is then interpreted by using table r, on dk=36-2=34 with confidence level of 95% or margin error of 5%, r calculation (0.632) is between 0.60 – 0.799 (strong). Based on the result of the research, it can be concluded that Islamic teaching has a strong or positive influence towards the student’s attitudes at SMK Kesehatan Samarinda.

Exact Formulation of Moments for Density of States on Multisite Correlation Function under Constant Composition

For a classical discrete system on a periodic lattice under a constant composition, we show that the multivariate any-order moment for the configurational density of states (CDOS) before applying p...

Surface-Volume-Surface EFIE for Electromagnetic Analysis of 3-D Composite Dielectric Objects in Multilayered Media

The surface-volume-surface electric field integral equation (SVS-EFIE) is generalized for the case of scattering problems on the composite nonmagnetic dielectric objects situated in planar nonmagnetic layered medium. The piece-wise homogeneous regions of the scatterer can be arbitrarily positioned with respect to the layers of stratification. The SVS-EFIE being a class of single-source integral equations is formed by restricting the surface single-source electric field representation in each distinct region of the scatterer through the volume-EFIE (V-EFIE) enforced on the boundary of that region for only the tangential component of the total field. As a result, the SVS-EFIE utilizes only the electric field dyadic Green's functions. This allows for its cast into the mixed-potential form using classical Michalski-Zheng's formulation and method of moments (MoM) discretization featuring easily computable integrals with singularities no stronger than 1/R, R being the distance from the source to the observation point in such integrals. The matrices of MoM discretization are represented inhierarchical form (as H-matrices) enabling solution of the scattering problems in multilayered media with O(N <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">α</sup> log N) CPUtimeand memory complexities, where α is a geometry-dependent constant ranging from 1 to 1.5 depending on the shape of the scatterer. While the MoM surface and volume meshes discretizing the regions of the scatterer are constructed to ensure that no mesh element crosses interfaces between the layers, the clusters of both the surface and volume elements in their respective recursive partitionings in the process of H-matrix construction are allowed to span multiple layers of the medium. Upon computation of the layered medium Green's function kernels with the discrete complex image method allowing clusters of elements to cross dielectric interfaces between the layers is shown to preserve compressibility of the corresponding H-matrix blocks.

Doi–Peliti path integral methods for stochastic systems with partial exclusion

Doi–Peliti methods are developed for stochastic models with finite maximum occupation numbers per site. We provide a generalized framework for the different Fock spaces reported in the literature. Paragrassmannian techniques are then utilized to construct path integral formulations of factorial moments. We show that for many models of interest, a Magnus expansion is required to construct a suitable action, meaning actions containing a finite number of terms are not always feasible. However, for such systems, perturbative techniques are still viable, and for some examples, including carrying capacity population dynamics, and diffusion with partial exclusion, the expansions are exactly summable.

Revisiting bending theories of elastic gradient beams

In this paper, we discuss a problem of Bernoulli–Euler beam models development in the frame of the strain gradient and distortion gradient elasticity theories. Contradiction between some known size-dependent gradient beam models and analytical and numerical three-dimensional solutions found for the beam bending problems is shown. In particular, it is shown that in semi-inverse analytical solutions for a beam pure bending problem, the inverse squared dependence of normalized bending stiffness on the beam thickness could arise only due to wrong definition of the resultant bending moment and improper formulation of the boundary conditions on the top and bottom surfaces of the beam. In the correct semi-inverse solutions, finite values of normalized bending stiffness for ultra-thin gradient beams arise. The obtained results are also confirmed on the basis of 3D FE simulations realized for a pure and cantilever beam bending problems in the frame of simplified strain gradient elasticity theory. As a result, it is shown that the only correct approach for Bernoulli–Euler beam models development in gradient theories should ensures the fulfillment of boundary conditions on the top and bottom surfaces of the beam and corresponds to a model that assumed a uniaxial stress state of the beam. The consistent variational algorithm for the correct gradient beam models derivation is proposed.

Parameter-free quaternary orthogonal moments for color image retrieval and recognition

In order to describe color images, the use of the algebra of quaternions in combination with existing image orthogonal moments, meant for binary and grayscale images, has been widely investigated. This is because of their advantages in (1) gathering the three-channel color information in a single feature vector while preserving the correlation between them and in (2) eliminating shape information redundancy. However, the computation of these quaternary orthogonal moments depends on a unit pure quaternion parameter. The optimal value of this latter can be fixed only with the help of experiments and it is application-dependent. We propose a parameter-free formulation of the quaternary orthogonal moments. The general formula for the computation of the proposed moments, whose rotation invariance is achieved by retaining the modulus, is provided. Furthermore, experiments are conducted to evaluate the performance of the proposed modulus-based moment invariants for color image retrieval and recognition.

Wait–Hill MoM for a Lumped Element Loaded Mesh Screen on a Stratified Substrate

The generalized thin-wire Wait–Hill method of moments formulation in free space is extended to model plane wave scattering from a lumped element periodically loaded mesh screen backed by a multilayer substrate. It is numerically demonstrated that the sawtooth function methodology proposed by Hill and Wait for reducing the computation time is applicable. Furthermore, for the case of an electrically dense mesh, a simple analytical expression for the transmission coefficient is obtained.

Gaussian-windowed frame based method of moments formulation of surface-integral-equation for extended apertures

Scattering or coupling of electromagnetic beam-field at a surface discontinuity separating two homogeneous or inhomogeneous media with different propagation characteristics is formulated using surface integral equation, which are solved by the Method of Moments with the aid of the Gabor-based Gaussian window frame set of basis and testing functions. The application of the Gaussian window frame provides ( i ) a mathematically exact and robust tool for spatial-spectral phase-space formulation and analysis of the problem; ( ii ) a system of linear equations in a transmission-line like form relating mode-like wave objects of one medium with mode-like wave objects of the second medium; ( iii ) furthermore, an appropriate setting of the frame parameters yields mode-like wave objects that blend plane wave properties (as if solving in the spectral domain) with Green's function properties (as if solving in the spatial domain); and ( iv ) a representation of the scattered field with Gaussian-beam propagators that may be used in many large (in terms of wavelengths) systems.

Optimization and large scale computation of an entropy-based moment closure

We present computational advances and results in the implementation of an entropy-based moment closure, MN, in the context of linear kinetic equations, with an emphasis on heterogeneous and large-scale computing platforms. Entropy-based closures are known in several cases to yield more accurate results than closures based on standard spectral approximations, such as PN, but the computational cost is generally much higher and often prohibitive. Several optimizations are introduced to improve the performance of entropy-based algorithms over previous implementations. These optimizations include the use of GPU acceleration and the exploitation of the mathematical properties of spherical harmonics, which are used as test functions in the moment formulation. To test the emerging high-performance computing paradigm of communication bound simulations, we present timing results at the largest computational scales currently available. These results show, in particular, load balancing issues in scaling the MN algorithm that do not appear for the PN algorithm. We also observe that in weak scaling tests, the ratio in time to solution of MN to PN decreases.

Finite Element Analysis of a Bending Moment Formulation for the Vibration Problem of a Non-homogeneous Timoshenko Beam

In this paper we analyze a low-order finite element method for approximating the vibration frequencies and modes of a non-homogeneous Timoshenko beam. We consider a formulation in which the bending moment is introduced as an additional unknown. Optimal order error estimates are proved for displacements, rotations, shear stress and bending moment of the vibration modes, as well as a double order of convergence for the vibration frequencies. These estimates are independent of the beam thickness, which leads to the conclusion that the method is locking free. For its implementation, displacements and rotations can be eliminated leading to a well posed generalized matrix eigenvalue problem for which the computer cost of its solution is similar to that of other classical formulations. We report numerical experiments which allow us to assess the performance of the method.

Entire-Domain Basis Function MoM Formulation for a Substrate Backed Periodically Loaded Array of Narrow Strips

Wait’s entire-domain basis function method of moments matrix formulation for modeling scattering from periodically loaded wires in free space is modified using the current edge approximation and extended to include a multilayer substrate. From this matrix formulation, novel analytical formulations for the current and the effective transfer impedance are obtained. The convergence of the matrix and analytical formulations is improved with the aid of an expression by VanKoughnett. Furthermore, for the case of an electrically dense array, the analytical expression of the effective transfer impedance leads to a simple impedance model which is more general than previously published expressions.

Gold Nanorod-pNIPAM Hybrids with Reversible Plasmon Coupling: Synthesis, Modeling, and SERS Properties.

The thermoresponsive optical properties of Au nanorod-doped poly(N-isopropylacrylamide) (Au NR-pNIPAM) microgels with different Au NR payloads and aspect ratios are presented. Since the volume phase transition of pure pNIPAM microgels is reversible, the optical response reversibility of Au NR-pNIPAM hybrids is systematically analyzed. Besides, extinction cross-section and near-field enhancement simulations for Au NR-microgel hybrids are performed using a new numerical method based on the surface integral equation method of moments formulation (M3 solver). Additionally, the Au NR-microgel hybrid systems are expected to serve as excellent broadband surface-enhanced Raman scattering (SERS) substrates due to the temperature-controlled formation of hot spots and the tunable optical properties. The optical enhancing properties related to SERS are tested with three laser lines, evidencing excitation wavelength-dependent efficiency that can be easily controlled by either the aspect ratio (length/width) of the assembled Au NR or by the Au NR payload per microgel. Finally, the SERS efficiency of the prepared Au NR-pNIPAM hybrids is found to be stable for months.

Low Frequency Modelling of Layered Media for Logging While Drilling Applications Using FDTD

In a typical Logging While Drilling (LWD) ap- plication, several coils operating in the frequency range of a few KHz to MHz are used as transmitters and receivers to appropriately characterize the earth formation. Electromagnetic modelling of such a low frequency system poses serious computational challenges. In the Method of Moment (MoM) formulation, contribution of vector potential to the total field becomes several orders of magnitude smaller than that of the scalar potential, thus making the resultant matrix highly ill-conditioned. Finite Difference Time Domain (FDTD) method, on the other hand, requires enormous number of time steps to capture the low frequency information. In this paper, we consider a layered-earth model and compute the electromagnetic field due to electric and magnetic dipoles embedded in the formation. To address the low frequency problem in FDTD, we consider the source and the receiver dipoles to be infinitesimally small and aligned with the computational grid, and we modify the update equations accordingly. This approach reduces the time convergence of FDTD by two-to-three orders of magnitude, and also reduces the memory requirements by the same factor. Numerical results for the fields reflected from the layered interfaces and the corresponding voltages induced in the receive coils are presented for multiple scenarios involving shale and sand zones.

Evaluation of a Moments-Based Formulation for the Transport and Deposition of Small Inertia Aerosols

This paper introduces and evaluates a formulation for the modeling of transport and wall deposition of aerosols, written in terms of moments of the particle size distribution (PSD). This formulation allows coupling the moment methods with computational fluid dynamics (CFD) to track the space and time evolution of the PSD of an aerosol undergoing transport, deposition and coagulation. It consists in applying the quadrature method of moments (QMOM) to the diffusion-inertia model of Zaichik et al. [6], associated with the dynamic boundary layer (DBL) approach of Simonin [8] for wall deposition. After presenting the QMOM formulation of the transport equation and of the DBL wall function, the paper presents several test cases in which the method is compared to existing experimental and numerical results. It is shown that the moment formulation of the model does not introduce particular bias compared to its concentration-based formulation. This extension of the diffusion-inertia/DBL approach to the QMOM method hence allows modeling with a good numerical efficiency and at building scale the dynamics of aerosols undergoing transport and modification of their PSD through coagulation and deposition.

Stabilised finite element methods for a bending moment formulation of the Reissner-Mindlin plate model

This work presents new stabilised finite element methods for a bending moments formulation of the Reissner-Mindlin plate model. The introduction of the bending moment as an extra unknown leads to a new weak formulation, where the symmetry of this variable is imposed strongly in the space. This weak problem is proved to be well-posed, and stabilised Galerkin schemes for its discretisation are presented and analysed. The finite element methods are such that the bending moment tensor is sought in a finite element space constituted of piecewise linear continuos and symmetric tensors. Optimal error estimates are proved, and these findings are illustrated by representative numerical experiments.

Toward ultimate nanoplasmonics modeling.

Advances in the field of nanoplasmonics are hindered by the limited capabilities of simulation tools in dealing with realistic systems comprising regions that extend over many light wavelengths. We show that the optical response of unprecedentedly large systems can be accurately calculated by using a combination of surface integral equation (SIE) method of moments (MoM) formulation and an expansion of the electromagnetic fields in a suitable set of spatial wave functions via fast multipole methods. We start with a critical review of volume versus surface integral methods, followed by a short tutorial on the key features that render plasmons useful for sensing (field enhancement and confinement). We then use the SIE-MoM to examine the plasmonic and sensing capabilities of various systems with increasing degrees of complexity, including both individual and interacting gold nanorods and nanostars, as well as large random and periodic arrangements of ∼1000 gold nanorods. We believe that the present results and methodology raise the standard of numerical electromagnetic simulations in the field of nanoplasmonics to a new level, which can be beneficial for the design of advanced nanophotonic devices and optical sensing structures.

Design of a Circular Disc Microstrip Antenna Loaded By Annular Ring

The research contained in this thesis is a theoretical study of antenna design and calculation of the radiation fields using electric fields integral equation (EFIE) and magnetic field integral equation (MFIE). These equation have been converted, using the method of moments formulation of electromagnetic radiation in this these based onthe bodies of revolution (BoR),which are generated by revolution a planar curve about an axis called axis of symmetry. To find an unknown electric current density on the surface of the conductor ,and both unknowns electric and magnetic density current on the surface of the dielectric which are responsible for the generation of radiationfields in the space for the components (Eθ ,Eφ) ,the surface currents was represented by a set of basis functions that give the Fourier series because the body has a circular symmetry property and then select a set of weighted functions to find a linear system by using Galerkin method which requires that the weighted functions are equal to the complex conjugate of the current JW = )( * .

Locking-free finite element method for a bending moment formulation of Timoshenko beams

In this paper we study a finite element formulation for Timoshenko beams. It is known that standard finite elements applied to this model lead to wrong results when the thickness of the beam is small. Here, we consider a mixed formulation in terms of the transverse displacement, rotation, shear stress and bending moment. By using the classical Babuška–Brezzi theory, it is proved that the resulting variational formulation is well posed. We discretize it by continuous piecewise linear finite elements for the shear stress and bending moment, and discontinuous piecewise constant finite elements for the displacement and rotation. We prove an optimal (linear) order of convergence in terms of the mesh size for the natural norms and a double order (quadratic) in L2-norms for the shear stress and the bending moment. These estimates involve constants and norms of the solution that are proved to be bounded independently of the beam thickness, which ensures the locking-free character of the method. Numerical tests are reported in order to support our theoretical results.

The Effect of the Secondary Bending Moment on the Fracture Strength Evaluation of the Laser Welded Joints from a Web Core Sandwich Structure

During the last period the interest on the sandwich structures has became more favorable due to the strength to weight ratio. In the same manner, in ship building field the lightweight structures became more and more attractive. With increasing the usage fields has increased the need to study the behavior of these structures. In general all the sandwich structures loaded in bending shows an effect of the secondary bending moment. In the case of web core sandwich panels used in ship structures has been observed a pronounced effect of the secondary bending moment on laser welded joints. Considering this, the paper presents an analysis of the fracture strength of laser welded joints of a web core sandwich structure, due to the effect of secondary bending moment. In the first part, the paper analytical formulation of the secondary bending moments and their effect on welded joints. This effect is explained on the basis of angle α defined in the paper and which depends on the thickness of the face plate, the thickness of the web plate and respectively the height. The paper continues with a numerical analysis of the stress and strain state from a web core sandwich beam and where also it is analyzed the effect of the secondary bending moment on the fracture strength of laser welded joints. Based on the carried out study it was observed that for high thickness of the web plate the effect of secondary bending moments is the overloading of the welded joints, instead for small thickness of the web plate the effect of the secondary bending moments can be of the unloading the welded joints. However, a small thickness of the web plate can affect the rigidity of the structure. Therefore, based on this study was proposed a solution to reduce the secondary bending moment without reducing the stiffness of the sandwich panel. The analysis conducted in this paper can be a design criterion for the web core sandwich structures.

Matrix formulation of higher-order moments of partially coherent beams propagating through atmospheric turbulence along a slanted path

Based on the extended Huygens–Fresnel principle, the matrix formulae of higher-order moments of partially coherent beams propagating through atmospheric turbulence along a slanted path are derived by using the Wigner distribution function (WDF). The same matrix formulae for propagation along a vertical path, a horizontal path and in free space are discussed as special cases of our general results. Analytical expressions for the important turbulence parameters contained in the matrix formulae of higher-order moments are also derived.