A QoS aware optimal node deployment in wireless sensor network using Grey wolf optimization approach for IoT applications

The growth of Wireless Sensor Networks (WSN) becomes the backbone of all smart IoT applications. Deploying reliable WSNs is particularly significant for critical Internet of Things (IoT) applications, such as health monitoring, industrial and military applications. In such applications, the WSN’s inability to perform its necessary tasks and degrading QoS can have profound consequences and can not be tolerated. Thus, deploying reliable WSNs to achieve better Quality of Service (QoS) support is a relatively new topic gaining more interest. Consequently, deploying a large number of nodes while simultaneously optimizing various measures is regarded as an NP-hard problem. In this paper, a Grey wolf-based optimization technique is used for node deployment that guarantees a given set of QoS metrics, namely maximizing coverage, connectivity and minimizing the overall cost of the network. The aim is to find the optimum number of appropriate positions for sensor nodes deployment under various p-coverage and q-connectivity configurations. The proposed approach offers an efficient wolf representation scheme and formulates a novel multi-objective fitness function. A rigorous simulation and statistical analysis are performed to prove the proposed scheme’s efficiency. Also, a comparative analysis is being carried with existing state-of-the-art algorithms, namely PSO, GA, and Greedy approach, and the efficiency of the proposed method improved by more than 11%, 14%, and 20%, respectively, in selecting appropriate positions with desired coverage and connectivity.

     

Future IoT‐enabled threats and vulnerabilities: State of the art,challenges, and future prospects

In the recent era, the security issues affecting the future Internet‐of‐Things (IoT) standards has fascinated noteworthy consideration from numerous research communities. In this view, numerous assessments in the form of surveys were proposed highlighting several future IoT‐centric subjects together with threat modeling, intrusion detection systems (IDS), and various emergent technologies. In contrast, in this article, we have focused exclusively on the emerging IoT‐related vulnerabilities. This article is a multi‐fold survey that emphasizes on understanding the crucial causes of novel vulnerabilities in IoT paradigms and issues in existing research. Initially, we have emphasized on different layers of IoT architecture and highlight various emerging security challenges associated with each layer along with the key issues of different IoT systems. Secondly, we discuss the exploitation, detection, and defense methodologies of IoT malware‐enabled distributed denial of service (DDoS), Sybil, and collusion attack capabilities. We have also discussed numerous state‐of‐the‐art strategies for intrusion detection and methods for IDS setup in future IoT systems. Third, we have presented a brief classification of existing IoT authentication protocols and a comparative analysis of such protocols based on different IoT‐enabled cyber attacks. For conducting a real‐time future IoT research, we have presented some emerging blockchain solutions. We have also discussed a comparative examination of some of the recently developed simulation tools and IoT test beds that are characterized based on different layers of IoT infrastructure. We have also outlined some of the open issues and future research directions and also facilitate the readers with broad classification of existing surveys in this domain that addresses several scopes related to the IoT paradigm. This survey article focuses in enabling IoT‐related research activities by comparing and merging scattered surveys in this domain.     

Integrated Load Balancing and Void Healing Routing with Cuckoo Search Optimization Scheme for Underwater Wireless Sensor Networks

Wireless Personal Communications - In underwater wireless sensor networks, routing play a vital role in selecting an optimal path for packet forwarding. In routing scheme, most of the existing work...     

Coastal currents from Jason-2 and SARAL/AltiKa in the Indian region

In this study, data from space-based altimeters (Jason-2 and Satellite for ARgos and AltiKa [SARAL/AltiKa]) have been used to compute alongshore geostrophic currents in the coastal regions of the Indian mainland. These derived currents are compared with high-frequency (HF) radar observations. Beyond 30–40 km away from the coastline, altimeter-derived currents match fairly well with the HF radar data. Root mean square error (RMSE) of Jason-2-derived currents ranges between 0.3 and 0.6 m s^?1 while the same in the case of SARAL/AltiKa lies between 0.3 and 0.7 m s^?1. Satellite-derived across-track geostrophic current components (alongshore current) were also used to study the spatiotemporal variations of the east India coastal current (EICC). The coastal trapping of the EICC, its annual and intra-seasonal peaks are clearly observed in the power spectrum of time-series of Jason-2 and SARAL/AltiKa derived currents.     

The case analysis on sentiment based ranking of nodes in social media space

Now-a-days, social network sites have become quite popular for communication in the society. People have entangled their day-to-day activities around social media platforms. Social Networks have allowed the users to share their opinions on different topics. In social media, sentiment analysis is an important character to determine opinions of users. Moreover, user’s can be ranked to determine their relative influence. This paper proposes a methodology to rank the users involving sentiment related parameters such as likes, comments and corresponding likescount. Analysis of users’ comments is carried-out. Weights are assigned to these parameters and scores are calculated for each user. Users are ranked on the basis of scores obtained and compared with existing technique. In order to verify the effectiveness of proposed methodology, data is extracted from a verified Facebook page ‘Panjab University, Chandigarh’. Mean, standard deviation and variance are computed to capture the usefulness of ranks obtained by the proposed method. Results depict that the proposed methodology is better than existing technique since it incorporates several features indicating positive and negative behavior of users. This technique can be used to determine the highly trusted and the most distrusted users in a social media user’s profile. Users with negative scores can be considered for outlier analysis. The proposed methodology can also be extended to work on other social media platforms.     

WEB-Spline-based mesh-free finite element approximation for p-Laplacian

In this paper, we discuss the approximation of p-Laplace problem using WEB-Spline based mesh free finite elements. Along with usual weak formulation, we also consider the mixed formulation of the p-Laplace problem. We give existence, uniqueness results for both continuous and discrete problems. We also provide a priori error estimates for both the formulations.     

Triple‐band metamaterial‐inspired antenna using FDTD technique for WLAN/WiMAX applications

In this article, a triple‐band metamaterial (MTM)‐inspired antenna has been designed and analyzed using finite difference time domain technique (FDTD). The proposed MTM consists of two L‐dumbbell‐shaped unit cells, feed, and partial ground plane. The proposed antenna shows triple‐band characteristics with impedance bandwidths of 10.6, 4.67, and 26.8% centered at 2.4, 3, and 5.7 GHz, respectively. The first two bands are working at zeroth‐order resonating mode and first‐order resonating mode while third is due to series slot and coupling between feed and ground plane. It offers compact nature with total antenna size of 30 × 30 × 1.6 mm³. The proposed triple‐band antenna has been designed and analyzed using FDTD code based on convolutional perfectly matched layer boundary conditions and HFSS as well. The prototype antenna has also been fabricated and tested experimentally to validate the simulation results. The proposed antenna exhibits good radiation characteristics throughout the working bands. © 2015 Wiley Periodicals, Inc. Int J RF and Microwave CAE 25:688–695, 2015.     

Triple band omnidirectional miniaturized metamaterial inspired antenna using flipped rectangular stub for LTE,WiMAX, and WLAN applications

In this article, a miniaturized metamaterial (MTM) inspired antenna with triple band characteristics is presented for LTE/WLAN/WiMAX applications. The antenna mainly consists of a square shaped split ring resonator (SRR) with rectangular stub connected in the outward direction. Due to inward flipping of the same rectangular stub leads to 20% antenna miniaturization without degrading the resonance behavior. The SRR produces first and second band, while the third band is enhanced due to flipping of inward stub and addition of rectangular type slot in the partial ground plane. The antenna exhibits tri‐band characteristics with each bands centered at 2.23, 3.65, and 5.13 GHz, having ?10 dB impedance bandwidth of 9.42%, 12.88% and 15.34% for the first, second, and third band, respectively. The antenna has a footprint size as low as 0.16 λ₀ × 0.18 λ₀ × 0.012 λ₀ corresponding to 2.23 GHz with a measured gain of 2.22, 2.31, and 1.98 dBi., and measured radiation efficiency of 70%, 72.75% and 82.57% in the three bands, respectively. The prototype of the antenna is fabricated and simulated results are verified through measurements.     

Stacked rectangular dielectric resonator antenna with different volumes for wideband circular polarization coupled with step‐shaped conformal strip

This paper presents a wideband circularly polarized broadside radiation characteristics by using stacked rectangular dielectric resonator antenna (DRA) with different volumes. In this designed antenna, the wide input impedance‐ and axial ratio (AR)‐bandwidths come from three factors: stacked rectangular DR with different volumes, stepped‐shaped conformal strip associated with microstrip line as a feed and different type of partial ground plane. Here, the orthogonal TE^x_δ11 and TE^y_1δ1 modes have been responsible for the generation of CP radiation in stacked rectangular DRA. Measured results show that the proposed stacked rectangular DRA with different volumes achieves input impedance bandwidth of 54.84% while AR bandwidth has been found to be 11.53%. The proposed antenna provides broadside right‐handed CP radiation pattern with gain ranges from 2.27–5.80 dBic and offers an average radiation efficiency of 89.48%, across the entire working bandwidth, respectively. Therefore, this antenna is very much useful for the ISM 2400 band applications.     

Compact ultrathin conformal metamaterial dual‐band absorber for curved surfaces

A compact, ultrathin conformal metamaterial dual‐band absorber for curved surfaces has been presented in this article. The absorber unit cell composed of circular and split ring resonators which are connected with plus‐shaped structure. The proposed absorber unit cell is compact in size (0.22λ_o × 0.22λ_o) and as well as ultrathin thickness (0.006λ_o), where λ_o is the wavelength at 5.8 GHz. The designed absorber gives two absorption tips at 5.8 and 7.7 GHz with more than 90% absorptivity. The full width at half maximum bandwidths are 220 MHz (5.67‐5.89 GHz) and 250 MHz (7.58‐7.83 GHz). The proposed conformal absorber is sensitive to the polarization angle and has a stable absorptivity over a wide range of incident electromagnetic wave. The parametric analysis and equivalent transmission line model have been investigated. The surface current and electric field distribution also discussed for understanding the absorption mechanism. To analyze the performance of proposed absorber on the curved surfaces, it is wrapped on the different radius of cylindrical surface and measured the absorptivity. Simulated and measured results have good agreement between them.