A Node Placement Algorithm Utilizing Mobile Nodes in WSN and IoT Networks

The operation of the Internet of Things (IoT) networks and Wireless Sensor Networks (WSN) is often disrupted by a number of problems, such as path disconnections, network segmentation, node faults, and security attacks. A method that gains momentum in resolving some of those issues is the use of mobile nodes or nodes deployed by mobile robots. The use of mobile elements essentially increases the resources and the capacity of the network. In this work, we present a Node Placement Algorithm with two variations, which utilizes mobile nodes for the creation of alternative paths from source to sink. The first variation employs mobile nodes that create locally-significant alternative paths leading to the sink. The second variation employs mobile nodes that create completely individual (disjoint) paths to the sink. We then extend the local variation of the algorithm by also accounting for the energy levels of the nodes as a contributing factor regarding the creation of alternative paths. We offer both a high-level description of the concept and also detailed algorithmic solutions. The evaluation of the solutions was performed in a case study of resolving congestion in the network. Results have shown that the proposed algorithms can significantly contribute to the alleviation of the problem of congestion in IoT and WSNs and can easily be used for other types of network problems.

Analysis and evaluation of the effect of reflectance values on internal walls, internal roofs, and light shelf on optimal illumination levels in the diploma economics and business building of the vocational school UGM, Yogyakarta

The use of natural light as a source of lighting in buildings is an option in energy saving. One of the efforts that has been made is the installation of a light shelf. The light shelf installed in the UGM Vocational School Economics and Business Diploma (DEB SV) building is not fully working optimally. As many as 83% of the light shelf in lecture rooms is covered by curtains because it is considered to produce excess light (glare). This results in a greater consumption of lighting electricity. This study was conducted to analyze and evaluate the effect of the reflectance value (color) attached to the internal walls, internal roof, external light shelf, and internal light shelf on the indicator of illumination levels Useful Daylight Illuminance (UDI). Furthermore, this study aims to determine the optimum reflectance value (color) parameter. The research was conducted with a simulation method using RadianceIES in the IESVE 2021 software. The first simulation results show the value of reflectance (color) installed (base case) on the internal wall, internal roof, external light shelf, and internal light shelf in one of the lecture rooms of the DEB SV UGM building resulting in a very large value of the UDI>2000lux indicator, which is 84,9% (not according to the criteria). The results of the second simulation provide two variations of the optimum reflectance (color) parameters in the independent variable. The first variation is the internal walls, internal roof, external light shelf, and internal light shelf, each of which has a reflectance value (color) of 90,67% (beige), 100% (white), 90,67% (beige), and 100% (white). The second variation is the internal walls, internal roof, exte rnal light shelf, and internal light shelf, each of which has a reflectance value (color) of 90,67% (beige), 100% (white), 90,67% (beige), and 90,67% (beige).

Characteristics of Mixed Porus Asphalt with Combination of LDPE, CPO and PEN 60/70

The quality of the road depends on the pavement, drainage conditions, and materials. For this reason, it is necessary to make innovations in improving the quality of road pavement, one of which is increasing the material. There are many types of pavements, one of which is porous asphalt pavement. Porous asphalt has many cavities that is easy for water to pass but has a low stability value with high permeability. This research will utilize Low Density Poly Ethylene (LDPE), as an additive, CPO, and Pen 60/70 in a porous asphalt mixture. The purpose of this study was to determine the characteristics of the porous asphalt mixture by substituting LDPE and CPO for Pen 60/70. The method used in analyzing the characteristics of the porous asphalt mixture refers to the specifications of the Australis Asphalt Pavement Association (AAPA) (2014), with parameters Camtabro Loss (CL), Asphalt Flow Down (AFD), VIM, stability and flow. The gradation used in this study is an open gradation. This research was started from determining the value of Optimum Asphalt Content (KAO), with two variations, namely Variation 1 (1% LDPE, 10% CPO, 89% pen 60/70), variation 2 (5% LDPE, 10% CPO, 85% Pens 60/70). The KAO value of variation 1 is 5.03% and the second variation is 4.75%. After obtaining the KAO value, LDPE and CPO are substituted. The test results for the porous asphalt mixture for CL values were 34.12% and 27.07%, respectively; AFD value of 0.13% and 0.12%; for the VIM value of 14.90% and 19.03%; stability value 603.24 kg and 603.19 kg; and flow values are 5.03 mm and 4.80 mm. In general, the value obtained from the test meets the required requirements. However, the durability value of the mixture did not meet the requirements, namely 60.15% and 48.22%, with the condition >90%.

Construction of exact minimal parking garages: nonlinear helical motifs in optimally packed lamellar structures

Minimal surfaces arise as energy minimizers for fluid membranes and are thus found in a variety of biological systems. The tight lamellar structures of the endoplasmic reticulum and plant thylakoids are comprised of such minimal surfaces in which right- and left-handed helical motifs are embedded in stoichiometry suggesting global pitch balance. So far, the analytical treatment of helical motifs in minimal surfaces was limited to the small-slope approximation where motifs are represented by the graph of harmonic functions. However, in most biologically and physically relevant regimes the inter-motif separation is comparable with its pitch, and thus this approximation fails. Here, we present a recipe for constructing exact minimal surfaces with an arbitrary distribution of helical motifs, showing that any harmonic graph can be deformed into a minimal surface by exploiting lateral displacements only. We analyse in detail pairs of motifs of the similar and of opposite handedness and also an infinite chain of identical motifs with similar or alternating handedness. Last, we study the second variation of the area functional for collections of helical motifs with asymptotic helicoidal structure and show that in this subclass of minimal surfaces stability requires that the collection of motifs is pitch balanced.

BMO and Elasticity: Korn’s Inequality; Local Uniqueness in Tension

In this manuscript two BMO estimates are obtained, one for Linear Elasticity and one for Nonlinear Elasticity. It is first shown that the BMO-seminorm of the gradient of a vector-valued mapping is bounded above by a constant times the BMO-seminorm of the symmetric part of its gradient, that is, a Korn inequality in BMO. The uniqueness of equilibrium for a finite deformation whose principal stresses are everywhere nonnegative is then considered. It is shown that when the second variation of the energy, when considered as a function of the strain, is uniformly positive definite at such an equilibrium solution, then there is a BMO-neighborhood in strain space where there are no other equilibrium solutions.

Variational principles of nonlinear magnetoelastostatics and their correspondences

We derive the equations of nonlinear magnetoelastostatics using several variational formulations involving the mechanical deformation and an independent field representing the magnetic component. An equivalence is also discussed, modulo certain boundary integrals or constant integrals, between these formulations using the Legendre transform and properties of Maxwell’s equations. Bifurcation equations based on the second variation are stated for the incremental fields as well for all five variational principles. When the total potential energy is defined over the infinite space surrounding the body, we find that the inclusion of certain terms in the energy principle, associated with the externally applied magnetic field, leads to slight changes in the Maxwell stress tensor and associated boundary conditions. Conversely, when the energy contained in the magnetic field is restricted to finite volumes, we find that there is a correspondence between the discussed formulations and associated expressions of physical entities. In view of a diverse set of boundary data and the nature of externally applied controls in the problems studied in the literature, along with an equally diverse list of variational principles employed in modelling, our analysis emphasises care in the choice of variational principle and unknown fields so that consistency with other choices is also satisfied.

Control for the Space Tether System Motion

This paper proposed a study of a spatial tether system (STS), composed by two satellite (a main satellite and a subsatellite), with the objective of developing a control system in which the motion of the subsatellite is limited in the orbital plane of the main satellite. The linear quadratic regulator (LQR) method is used to implement this control, which is an optimal control with state feedback to predict the linearization of the equations of motion to calculate the feedback gain, using the resolution of Riccati equation. The results show an effective control, with the motion of the subsatellite limited only to the stretch of the cable that links both satellites. However, it is necessary to introduce an auxiliary torque, since the linearized equation associated with the second variation of the angle out of the plan does not have a term independent of the state vector.

Variational formulations of steady rotational equatorial waves

When the vorticity is monotone with depth, we present a variational formulation for steady periodic water waves of the equatorial flow in the f-plane approximation, and show that the governing equations for this motion can be obtained by studying variations of a suitable energy functional 𝓗 in terms of the stream function and the thermocline. We also compute the second variation of the constrained energy functional, which is related to the linear stability of steady water waves.

Stable s-minimal cones in ℝ3 are flat for s ~ 1

We prove that half spaces are the only stable nonlocal s-minimal cones in {\mathbb{R}^{3}}, for {s\in(0,1)} sufficiently close to 1. This is the first classification result of stable s-minimal cones in dimension higher than two. Its proof cannot rely on a compactness argument perturbing from {s=1}. In fact, our proof gives a quantifiable value for the required closeness of s to 1. We use the geometric formula for the second variation of the fractional s-perimeter, which involves a squared nonlocal second fundamental form, as well as the recent BV estimates for stable nonlocal minimal sets.

The Jacobi morphism and the Hessian in higher order field theory; with applications to a Yang–Mills theory on a Minkowskian background

We characterize the second variation of an higher order Lagrangian by a Jacobi morphism and by currents strictly related to the geometric structure of the variational problem. We discuss the relation between the Jacobi morphism and the Hessian at an arbitrary order. Furthermore, we prove that a pair of Jacobi fields always generates a (weakly) conserved current. An explicit example is provided for a Yang–Mills theory on a Minkowskian background.