3D node deployment strategies prediction in wireless sensors network

ABSTRACT

3D Deployment plays a fundamental role in setting up efficient wireless sensor networks (WSNs) and IoT networks. In general, WSN are widely utilised in a set of real contexts such as monitoring smart houses and forest fires with parachuted sensors. This study focus on planned 3D deployment in which the sensor nodes must be accurately positioned at predetermined locations to optimise one or more design objectives under some given constraints. The purpose of planned deployment is to identify the type, the number, and the locations of nodes to optimise the coverage, the connectivity and the network lifetime. There have been a large number of studies that proposed algorithms resolving the premeditated problem of 3D deployment. The objective of this study is twofold. The first one is to present the complexity of 3D deployment and then detail the types of sensors, objectives, applications and recent research that concerns the strategy used to solve this problem. The second one is to present a comparative survey between the recent optimisation strategies solving the problem of 3D deployment in WSN. Based on our extensive review, we discuss the strengths and limitations of each proposed solution and compare them in terms of WSN design factors.     

Convergence behavior and root signal sets of stack filters

The four different types of stack filters, type-0 through type-3, are determined by four different shapes of the on-set of the positive Boolean function from which the stack filter is constructed.Under all three appending strategies commonly considered in the literature-first and last value carry-on strategy, constant value carry-on strategy, and the circular approach-stack filters of type-0 through type-2 possess the convergence property, while type-3 stack filters do not all share this property. Examples of cyclic behavior in type-3 stack filters are given. Conditions under which certain operations on stack filters which possess the convergence property produce other filters with this property are provided.In perhaps the most important result in this paper, it is shown that the root signal set of any type-3 stack filter is the intersection of the root sets of the type-1 and type-2 stack filters from which the type-3 filter is constructed. This should simplify the task of finding the set of roots of type-3 stack filters.The rates of convergence for stack filters of type-1 and type-2 are determined for each appending approach. The convergence behavior and rates of convergence of stack filters of type-1 and type-2 are then generalized to include type-1 and type-2 filters with indexi.     

A Fast Adaptive Salt and Pepper Noise Reduction Method in Images

In this paper, an effective filtering method is proposed to remove impulse noise from images. In this two-stage method, detected noise-free pixels remain unchanged. Afterwards, a Gaussian filter with adaptive variances according to the image noise level is applied on the noisy pixels. Experimental results show that the proposed method outperforms recent impulse denoising methods in terms of PSNR, MAE, IEF, and SSIM. Moreover, the speed of the method is comparable with them, and it can be used effectively in real-time applications.     

Asymptotic BEP and SEP of Quadratic Diversity Combining Receivers in Correlated Ricean Fading, Non?Gaussian Noise, and Interference

In this paper, we study the asymptotic behavior of the bit-error probability (BEP) and the symbol-error probability (SEP) of quadratic diversity combining schemes such as coherent maximum-ratio combining (MRC), differential equal-gain combining (EGC), and noncoherent combining (NC) in correlated Ricean fading and non-Gaussian noise, which in our definition also includes interference. We provide simple and easy-to-evaluate asymptotic BEP and SEP expressions which show that at high signal-to-noise ratios (SNRs) the performance of the considered combining schemes depends on certain moments of the noise and interference impairing the transmission. We derive general rules for calculation of these moments and we provide closed-form expressions for the moments of several practically important types of noise such as spatially dependent and spatially independent Gaussian mixture noise, correlated synchronous and asynchronous co-channel interference, and correlated Gaussian interference. From our asymptotic results we conclude that (a) the asymptotic performance loss of binary frequency-shift keying (BFSK) with NC compared to binary phase-shift keying (BPSK) with MRC is always 6 dB independent of the type of noise and the number of diversity branches, (b) the asymptotic performance loss of differential EGC compared to MRC is always 3 dB for additive white Gaussian noise but depends on the number of diversity branches and may be larger or smaller than 3 dB for other types of noise, and (c) not only fading correlation but also noise correlation negatively affects the performance of quadratic diversity combiners.     

Three-dimensional accuracy with two-dimensional computation speed: using the Kiva™ numerical framework to improve foundation heat transfer calculations

Calculation of heat transfer from building foundations is a computationally intensive three-dimensional problem that can require several weeks to solve using current computing hardware. The Kiva numerical framework was developed to compare foundation heat transfer calculation methods and determine approaches that reduce computation time without sacrificing a balance of capability, ease-of-use, and accuracy. This paper demonstrates the application of the Kiva framework to determine an accurate method of approximating three-dimensional heat transfer effects using two-dimensional coordinate systems. In two-dimensions, problems that would otherwise take days or weeks to solve can be solved in less than a minute. Three existing two-dimensional approximation methods along with a new boundary layer adjustment method are tested across a range of foundation types, shapes, and insulation configurations. The boundary layer adjustment method is shown to provide results within 3% mean absolute deviation from the three-dimensional solution.     

TADAS dampers in very large deformations

Triangular-plate Added Damping and Stiffness (TADAS) dampers are special kinds of passive control devices that can be used in seismic design and retrofitting of structural systems. However, when exposed to large deformations, primary members of a structure can be in danger of serious damage due to improper geometric characteristics of these dampers. In this study, response of a one bay frame equipped with a TADAS device, previously tested in the laboratory, was simulated using a detailed FE model in ABAQUS. A monotonic analysis was then conducted on the TADAS damper alone, which indicated that in large deformations, TADAS damper pins hit the top of the holes, resulting in an abrupt stiffness increase in the damper. Seismic analysis of a six story moment resisting frame with TADAS dampers, using a series of twelve scaled earthquake ground motions, was also conducted in OpenSees which indicated that with sudden stiffness increase in dampers, the value of moments in beams as well as axial forces in braces will increase, causing possible damages in these areas. At the end, a method for calculating the optimal height for the holes in the damper was proposed, which is shown to be in good agreement with detailed ABAQUS models.     

PWM-switching pattern-based diagnosis scheme for single and multiple open-switch damages in VSI-fed induction motor drives

This paper deals with a fault detection technique for insulated-gate bipolar transistors (IGBTs) open-circuit faults in voltage source inverter (VSI)-fed induction motor drives. The novelty of this idea consists in analyzing the pulse-width modulation (PWM) switching signals and the line-to-line voltage levels during the switching times, under both healthy and faulty operating conditions. The proposed method requires line-to-line voltage measurement, which provides information about switching states and is not affected by the load. The fault diagnosis scheme is achieved using simple hardware and can be included in the existing inverter system without any difficulty. In addition, it allows not only accurate single and multiple faults diagnosis but also minimization of the fault detection time to a maximum of one switching period (T(c)). Simulated and experimental results on a 3-kW squirrel-cage induction motor drive are displayed to validate the feasibility and the effectiveness of the proposed strategy.     

Design of PSO‐based fuzzy logic controller for single axis magnetic levitation system

In this paper, a particle swarm optimization (PSO) method is proposed to design an optimal robust fuzzy logic controller (FLC). The objective of this paper is to design a nonlinear optimal robust controller for the single axis magnetic levitation system with high accuracy. PSO algorithm is applied to search globally optimal parameters of FLCs. Three different FLCs are designed. First, proportional derivative (PD)‐like FLC. Second, the FLC is based on the PSO algorithm to find the optimal range of the eight linguistic membership functions (FLC1 with PSO algorithm). Finally, the FLC is based on the PSO algorithm to find the optimal range and shape of the four linguistic membership functions (FLC2 with PSO algorithm). The performances of three different FLCs are compared. Simulation results show that PSO‐based optimal FLCs find the optimal range and shape of the four linguistic membership functions and achieved better performance than the other proposed controllers, minimizing 48 fuzzy rules. © 2011 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Geochemistry of episodic sedimentation in Bizerte Lagoon,northern Tunisia

The decrease of the contents of TOC in sediment cores in the Bizerte Lagoon is synchronous with that of carbonates. This is attributed to a dilution phenomenon of the organic fraction by the carbonate component of the sediment in the lagoon. This phenomenon also can be explained by the effect of early diagenesis, resulting in the existence of more condensed products, or by removal of more labile organic fraction and/or by reorganization mechanisms leading to the solubilization of organic matter towards deep levels. It appears that the mechanisms controlling the geochemical sedimentation in the lagoon are similar to those observed today, with some occasional characteristics reflecting the impact of episodic phenomenon related to other factors and processes, especially a continental influence on the sediments, rather than marine influences.