Q-MOHRA: QoS Assured Multi-objective Hybrid Routing Algorithm for Heterogeneous WSN

Quality of Service (QoS) assurance in Wireless Sensor Network (WSN) is a tough task, and it is more exciting due to the scarcity of resources. The requirement of different WSN applications running over has different constraints. In QoS, routing protocol the network has to balance the traffic. This paper presents a novel heuristic routing algorithm known as QoS assured Multi-objective Hybrid Routing Algorithm (Q-MOHRA) for Heterogeneous WSN. Q-MOHRA takes into account the link (energy, hop count, link quality indicator etc.) and path (jitter) metrics for optimal path selection. The performance of Q-MOHRA is evaluated through intensive simulation and equated with Simple Hybrid Routing Protocol (SHRP) and Dynamic Multi-objective Routing Algorithm (DyMORA). The metrics such as average energy consumption, residual energy, packet delivery ratio, jitter, and normalized routing load are used for comparison. The performance of Q-MOHRA has been observed to outclass SHRP and DyMORA. It improves the packet delivery ratio by 24.31% as compared to SHRP and 11.86% as compared to DyMORA. Q-MOHRA outperforms DyMORA in terms of average energy consumption by a factor of 8.27%.     

An Investigation of Massive Gain in Hybrid Configurable Cylindrical Dielectric Resonator Antenna

Delay Tolerant Networks (DTNs) have attracted various interests these days. Since DTNs are subject to high loss rate, large delay, intermittent connection, and even no end-to-end connectivity, relay nodes, such as throwboxes, are deployed to enhance network performance. Internet-based systems have contemporaneous connectivity between location-distributed nodes, and this does not apply to DTNs. Thus, the traditional relay node deployment strategies are no longer suitable for DTNs. In this paper, we propose a novel strategy, named Connection-2 (\(CO_2\)), to deploy throwboxes to enhance the fault tolerance of DTNs. \(CO_2\) constructs a 2-connected DTN using an approximation algorithm. Every mobile node in the 2-connected DTN can reach another mobile node via two or more node-disjoint paths within its mobility range. While enhancing fault tolerance, the number of throwboxes that \(CO_2\) requires is small. We conduct various experiments based on the simulation of the real Tuscaloosa bus transit system and compare its performance with two popular strategies. Experimental results show that \(CO_2\) is effective.     

A New Energy Efficient Hierarchical Routing Protocol for Wireless Sensor Networks

Wireless sensor networks consist of low cost sensor nodes which have limited power supplies, memory capacity, processing capability and transmission rate. Sensor nodes gather information from the environment and send the collected information to base station with help of a routing cooperation. Because of limited resources in Wireless Sensor Networks, fulfilling these routing operations is a major problem. Routing protocols are used to perform these operations. The most important thing by considering while these protocols are designed is energy efficiency. Because wireless sensor networks are widely used in intelligent systems, the energy efficiency of these networks is very important in IoT. Researchers have proposed several hierarchical routing protocols such as LEACH, PEGASIS, TEEN and APTEEN. In this study, an energy efficient routing protocol is developed which is more efficient than currently avaliable routing protocols. The developed protocol involves mapping of the network, sleep–wake/load balancing, data merge processes. The proposed protocol gives better results than other protocols in number of surviving nodes and amount of energy consumed criterias.     

Low Cost Low Power Smart Helmet for Real-Time Remote Underground Mine Environment Monitoring

Underground mining production process is vulnerable and highly dynamic in nature. Among the various causes of accidents in underground mine, major one is presence of flammable and noxious gases. Though many existing safety gadgets are there but they could not work reliably because of the typical nature of mines structure and production variability. Wireless data and communication network is also not successful because wireless communication in underground mine is significantly more challenging than through air. This work introduces the application of mobile wireless sensor network in order to monitor a variety of parameters in underground mines which have life threatening effects towards them. Each node of the network placed over the safety gear (helmet wore statutorily by every miner) comprises of various sensors depending on the requirement with microcontroller unit and other low power accessories. The proposed work has a unique feature that it will make the personnel aware about the situation of the gases present and surrounding by automatically generating different alarms and different light indicators. Other function of this device will be to transmit the data sensed by the sensors in the device to the control room wirelessly so that the responsible person would be aware of the situation. This work is focused on the design of such a prototype model for the underground mines with the aforementioned specification.     

Distributed Topology Construction in ZigBee Wireless Networks

Topology control is one of the important techniques in wireless multi-hop networks to preserve connectivity and extend the network lifetime. This is more significant in ZigBee, since the address assignment scheme is tightly coupled with topology construction. For example, there can be orphan nodes that cannot receive the network address and isolated from the network due to predefined network configurations. In this paper, we propose a distributed topology construction algorithm that controls the association time of each node in order to solve the orphan node problem in ZigBee as well as construct an efficient routing tree topology. The main idea of the distributed topology construction algorithm is to construct primary backbone nodes by propagating the invitation packets and controlling the association time based on the link quality. Since the dynamically selected primary nodes are spread throughout the network, they can provide backbone to accept the association requests from the remaining secondary nodes which are majority in a network. In the performance evaluation, we show that the proposed topology construction algorithm effectively solves the orphan node problem regardless of network density as well as provides efficient tree routing cost comparable to the approximation algorithm for degree constrained minimum routing cost tree (DC-MRCT) problem.     

Assessing Ink Transfer Performance of Gravure-Offset Fine-Line Circuitry Printing

In this study, the printing mechanism and performance of gravure-offset fine-line circuitry printing technology are investigated in terms of key printing parameters through experimental and theoretical analyses. First, the contact angles of the ink deposited on different substrates, blankets, and gravure metal plates are experimentally determined; moreover, their temperature and solvent content dependences are analyzed. Next, the ink solvent absorption and evaporation behaviors of the blankets at different temperatures, times, and numbers of printing repetitions are characterized by conducting experiments. In addition, while printing repeatedly, the surface characteristics of the blankets, such as the contact angle, vary with the amount of absorbed ink solvent, further affecting the ink transfer performance (ratio) and printing quality. Accordingly, the surface effect of the blanket due to ink solvent absorption on the ink contact angle is analyzed. Furthermore, the amount of ink transferred from the gravure plate to the blanket in the “off process” and from the blanket to the substrate in the “set process” is evaluated by conducting a simplified plate-to-plate experiment. The influences of loading rate (printing velocity), temperature, and solvent content on the ink transfer performance are addressed. Finally, the ink transfer mechanism is theoretically analyzed for different solvent contents using Surface Evolver. The calculation results are compared with those of the experiment.     

A First Principles Study of Ferroelectricity and Magnetism Coexisting in Fe-Doped K<Subscript>0.5</Subscript>Na<Subscript>0.5</Subscript>NbO<Subscript>3</Subscript>

First-principles calculations were performed to investigate the coexistence of ferroelectricity and magnetism in Fe-doped tetragonal K_0.5Na_0.5NbO₃ (KNN) with different Fe concentrations. It was found that all three systems can possess both magnetism and ferroelectricity, and the magnetism becomes stronger with an increase in the concentration of Fe. The magnetic properties are due to ferromagnetism of Fe, and the Fe-Nb and Fe-O bonds induce magnetic moments on Nb and O atoms. Ferroelectricity comes from the hybridization of Nb and O, as in the case of pure KNN. The predicted results provide insight into the origin of the induced magnetic moments and an approach for obtaining multiferroic materials.     

Multi-focus image fusion by local optimization over sliding windows

This article presents a technique to solve the problem of multi-focus image fusion. This technique is based on the maximization of a linear function with spatial coherence constraints. The final fused image is computed as the sum of the source images using a segmentation map. We can compute the segmentation map using the Simplex method, where the objective function includes one variable associated with each pixel. The Simplex method requires a huge amount of memory resources to produce it. We present an algorithm called CPW-S, which uses some strategies to solve the problem in a context with fewer variables; images are split into regions, thus reducing the computational effort. We present results for two pairs of synthetic images in order to quantify the results, obtaining more than \(98\%\) of pixel accuracy for the segmentation map. We also present results for several pairs of real images (widely used in the literature) and a triad of multi-focus images. The resulting fused images are qualitatively good for all the real images included in the experiments.     

Sound event detection in real-life audio using joint spectral and temporal features

Typical methods for overlapping sound event detection (SED) do not fully consider the joint spectral and temporal transition characteristics of the audio signal. They are generally based on training models using either separate data from each event class or mixed signals containing simultaneous sound events. This paper introduced a new approach for SED in real-life audio using Nonnegative Matrix Factor 2-D Deconvolution and RUSBoost techniques. The idea is to capture the two-dimensional joint spectral and temporal information from the time-frequency representation while possibly separating the sound mixture into several sources. In addition, the RUSBoost technique is utilized to address the class imbalance problem of the training data. The proposed approach is evaluated using the TUT Sound Event 2016 and 2017 datasets. The results showed that the proposed method outperformed the baseline methods. For the TUT Sound Event 2016 dataset, the proposed method reduced the total error rate by 5% while increasing the F1 score by 13.8%. For the TUT Sound Event 2017 dataset, the proposed method reduced the total error rate by 3% while increasing the F1 score by 8.1%.