Fingerprint Database Enhancement by Applying Interpolation and Regression Techniques for IoT-based Indoor Localization

Most applied indoor localization is based on distance and fingerprint techniques. The distance-based technique converts specific parameters to a distance, while the fingerprint technique stores parameters as the fingerprint database. The widely used Internet of Things (IoT) technologies, e.g., Wi-Fi and ZigBee, provide the localization parameters, i.e., received signal strength indicator (RSSI). The fingerprint technique advantages over the distance-based method as it straightforwardly uses the parameter and has better accuracy. However, the burden in database reconstruction in terms of complexity and cost is the disadvantage of this technique. Some solutions, i.e., interpolation, image-based method, machine learning (ML)-based, have been proposed to enhance the fingerprint methods. The limitations are complex and evaluated only in a single environment or simulation. This paper proposes applying classical interpolation and regression to create the synthetic fingerprint database using only a relatively sparse RSSI dataset. We use bilinear and polynomial interpolation and polynomial regression techniques to create the synthetic database and apply our methods to the 2D and 3D environments. We obtain an accuracy improvement of 0.2m for 2D and 0.13m for 3D by applying the synthetic database. Adding the synthetic database can tackle the sparsity issues, and the offline fingerprint database construction will be less burden. Doi: 10.28991/esj-2021-SP1-012 Full Text: PDF

Semi-Infinite Structure Analysis with Bimodular Materials with Infinite Element

The modulus of elasticity of some materials changes under tensile and compressive states is simulated by constructing a typical material nonlinearity in a numerical analysis in this paper. The meshless Finite Block Method (FBM) has been developed to deal with 3D semi-infinite structures in the bimodular materials in this paper. The Lagrange polynomial interpolation is utilized to construct the meshless shape function with the mapping technique to transform the irregular finite domain or semi-infinite physical solids into a normalized domain. A shear modulus strategy is developed to present the nonlinear characteristics of bimodular material. In order to verify the efficiency and accuracy of FBM, the numerical results are compared with both analytical and numerical solutions provided by Finite Element Method (FEM) in four examples.

A different approach for the fractional chemical model

This article analyzes and compares the two algorithms for the numerical solutions of the fractional isothermal chemical equations (FICEs) based on mass action kinetics for autocatalytic feedback, involving the conversion of a reactant in the Liouville-Caputo sense. The first method is based upon the spectral collocation method (SCM), where the properties of Legendre polynomials are utilized to reduce the FICEs to a set of algebraic equations. We then use the well-known method like Newton-Raphson method (NRM) to solve the set of algebraic equations. The second method is based upon the properties of Newton polynomial interpolation (NPI) and the fundamental theorem of fractional calculus. We utilize these methods to construct the numerical solutions of the FICEs. The accuracy and effectiveness of these methods is satisfied graphically by combining the numerical results and plotting the absolute error. Also, the absolute errors are tabulated, and a good agreementfound in all cases.

Bedrock to soil: In-situ measurement and analytical techniques for initial weathering of proglacial environments

<p>Dirt. It is more important than one might think. Soil, along with its bedrock-derived components, provides a nexus in the earth system for energy, nutrient, and atmospheric control; yet it is a finite resource. Soils are consumed, transported, and replenished by natural and anthropogenic forces. Weathering—both physical and chemical—is the key process breaking down and regenerating the ions and mineral constituents of soils, facilitating the pathways from solid bedrock to soil to the rest of the global ecosystem. Yet our understanding of weathering is incomplete and the available methods to investigate these processes are limited. Here, the fundamental processes of weathering are questioned by studying them at their origins, the rock surface. New techniques were developed in pursuit of quantifying weathering at small scales in-situ, to obtain the highest resolution measurements possible. These were carried out in the proglacial regions of two New Zealand glaciers, Brewster Glacier and Franz Josef Glacier. Proglacial bedrock environments provided a clean-slate model from which to measure incipient weathering at increasing exposure ages. To mitigate error, a holistic approach encompassing weathering signals from multiple angles was taken. Spatial characterisation was completed through the capture of structure-from-motion photogrammetry (SFM) at multiple scales of observation. The resultant three dimensional surface models had an average error of 1.06x10-1 mm. The models were characterised for weathering using roughness as a novel multi-point analysis of surface features, through two separate novel methods utilising global polynomial interpolation filtering and continuous wavelet transform analysis. Physical samples were collected from the field for cosmogenic radionuclide surface exposure age dating. Compositional analysis was performed through X-ray fluorescence, as well as electron microprobe analysis (EPMA). Nano-scale structural and compositional trends were investigated through optical analysis of backscatter electron imaging and secondary electron imaging. Non-directional roughness and volumetric analysis patterns present compelling information to support negligible weathering occurring on bedrock surfaces in proglacial environments. Lithologic variation was identified as a strong influence on the results. Compositional analysis demonstrated insignificant levels of chemical alteration between sites, corroborating the spatial modelling results. The lack of surficial weathering in highly productive weathering environments necessitates the role of additional weathering factors. Deep subsurface weathering was investigated and presents the strongest case as a major contributor to chemical denudation. Validating the presence of deep weathering in many environments critically alters the knowledge required to evaluate and predict patterns of landscape evolution. By establishing a better understanding of how bedrock weathers in-situ, the groundwork is laid for making more accurate and educated forecasts on how the earth system will respond to changes in the future.</p>

Bedrock to soil: In-situ measurement and analytical techniques for initial weathering of proglacial environments

<p>Dirt. It is more important than one might think. Soil, along with its bedrock-derived components, provides a nexus in the earth system for energy, nutrient, and atmospheric control; yet it is a finite resource. Soils are consumed, transported, and replenished by natural and anthropogenic forces. Weathering—both physical and chemical—is the key process breaking down and regenerating the ions and mineral constituents of soils, facilitating the pathways from solid bedrock to soil to the rest of the global ecosystem. Yet our understanding of weathering is incomplete and the available methods to investigate these processes are limited. Here, the fundamental processes of weathering are questioned by studying them at their origins, the rock surface. New techniques were developed in pursuit of quantifying weathering at small scales in-situ, to obtain the highest resolution measurements possible. These were carried out in the proglacial regions of two New Zealand glaciers, Brewster Glacier and Franz Josef Glacier. Proglacial bedrock environments provided a clean-slate model from which to measure incipient weathering at increasing exposure ages. To mitigate error, a holistic approach encompassing weathering signals from multiple angles was taken. Spatial characterisation was completed through the capture of structure-from-motion photogrammetry (SFM) at multiple scales of observation. The resultant three dimensional surface models had an average error of 1.06x10-1 mm. The models were characterised for weathering using roughness as a novel multi-point analysis of surface features, through two separate novel methods utilising global polynomial interpolation filtering and continuous wavelet transform analysis. Physical samples were collected from the field for cosmogenic radionuclide surface exposure age dating. Compositional analysis was performed through X-ray fluorescence, as well as electron microprobe analysis (EPMA). Nano-scale structural and compositional trends were investigated through optical analysis of backscatter electron imaging and secondary electron imaging. Non-directional roughness and volumetric analysis patterns present compelling information to support negligible weathering occurring on bedrock surfaces in proglacial environments. Lithologic variation was identified as a strong influence on the results. Compositional analysis demonstrated insignificant levels of chemical alteration between sites, corroborating the spatial modelling results. The lack of surficial weathering in highly productive weathering environments necessitates the role of additional weathering factors. Deep subsurface weathering was investigated and presents the strongest case as a major contributor to chemical denudation. Validating the presence of deep weathering in many environments critically alters the knowledge required to evaluate and predict patterns of landscape evolution. By establishing a better understanding of how bedrock weathers in-situ, the groundwork is laid for making more accurate and educated forecasts on how the earth system will respond to changes in the future.</p>

Threshold value estimation of journey-distance using generalized polynomial function

The present work demonstrates an experience in estimating the threshold value of journey distances travelled by transit passengers using generalized polynomial function. The threshold value of journey distances may be defined as that distance beyond which passengers might no more be interested to travel by their reported mode. A knowledge on this threshold value is realized to be useful to limit the upper-most slab of transit fare, while preparing of a length-based fare matrix table. Theoretically, the threshold value can be obtained at that point on the cumulative frequency distribution (CFD) curve of journey distances at which the maximum rate of change of the slope of curve occurs. In this work, the CFD curve of the journey distance values is empirically modelled using Newton’s Polynomial Interpolation method, which helps to overcome various challenges usually encountered while an assumption of a theoretical probability distribution is considered a priori for the CFD.

Parallel Adaptive Interpolation Algorithm based on Sparse Grids for Modeling Dynamic Systems with Interval Parameters

The paper presents a parallel algorithm for adaptive interpolation based on sparse grids for modeling dynamic systems with interval parameters. The idea of the algorithm is to construct a piecewise polynomial function that interpolates the dependence of the solution to the problem on the point values of the interval parameters. In the classical version of the algorithm, polynomial interpolation on complete grids is used, and with a large number of uncertainties, the algorithm becomes difficult to apply due to the exponential growth of computational costs. The use of sparse grids can significantly reduce the computational costs, but nevertheless the complexity of the algorithm in the general case remains exponential with respect to the number of interval parameters. In this regard, the issue of accelerating the algorithm is relevant. The algorithm can be divided into several sets of independent subtasks: updating the values corresponding to the grid nodes; calculation of weighting factors; interpolation of values at new nodes. The last two sets imply parallelization of recursion, so here the techniques for traversing the width of the call graph are mainly used. The parallel implementation of the algorithm was tested on two ODE systems containing two and six interval parameters, respectively, using a different number of computing cores. The results obtained demonstrate the effectiveness of the approaches used.

A New Beam Finite Element for Static Bending Analysis of Slender Transversely Cracked Beams on Two-Parametric Soils

This paper derives an original finite element for the static bending analysis of a transversely cracked uniform beam resting on a two-parametric elastic foundation. In the simplified computational model based on the Euler–Bernoulli theory of small displacements, the crack is represented by a linear rotational spring connecting two elastic members. The derivations of approximate transverse displacement functions, stiffness matrix coefficients, and the load vector for a linearly distributed load along the entire beam element are based on novel cubic polynomial interpolation functions, including the second soil parameter. Moreover, all derived expressions are obtained in closed forms, which allow easy implementation in existing finite element software. Two numerical examples are presented in order to substantiate the discussed approach. They cover both possible analytical solution forms that may occur (depending on the problem parameters) from the same governing differential equation of the considered problem. Therefore, several response parameters are studied for each example (with additional emphasis on their convergence) and compared with the corresponding analytical solution, thus proving the quality of the obtained finite element.

Full-scale self-propulsion simulation with a discretized propeller

A comparison between towing tank testing and full-scale CFD simulations is presented at three different target speeds. For the current self-propulsion simulation, the self-propulsion point was obtained using polynomial interpolation. The studies of boundary layer thickness, a basic grid uncertainty assessment and verification were performed to give some confidence of grid application to current self-propulsion simulation. All simulations are performed using a commercial CFD software STAR-CCM+. It is concluded that with high-fidelity numerical methods, it’s possible to treat hull roughness and directly calculate full-scale flow characteristics, including the effects of the free surface, none-linearity, turbulence and the interaction between propeller, hull and the flow field.

Topology optimization of laminated composite structures under harmonic force excitations

In this paper, a topology optimization approach for the design of laminated composite structures under harmonic force excitations is proposed. A novel method is developed to calculate the harmonic response for composite laminates, which consists of two steps: firstly, based on the strain energy approach, the damping matrix model of composite laminates is established with the proportional damping assumption; then, the displacement response is calculated by the mode acceleration method The design objective of topology optimization is to minimize the displacement amplitude at the concerning point with an excitation frequency or a frequency band. An extended polynomial interpolation scheme is introduced to penalize the stiffness, damped stiffness and mass of elements. The analytical sensitivities of the objective and constraint functions to the density variables are derived in detail, and the globally convergent method of moving asymptotes is used to solve the optimization problem. Numerical examples are performed to demonstrate the effectiveness and feasibility of the proposed topology optimization method in improving the dynamic performance of laminated composite structures. The influence rules of excitation frequency and layer sequence on topologic shape are also discussed.