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Beamforming combined with massive multiple-input multiple-output (MIMO) antenna arrays are expected to be the most important aspects of 5G and beyond wireless networks. In this paper, an 8 × 8 massive MIMO array with beamforming is proposed for 5G and beyond wireless applications. To develop this design, the substrate of polyimide material is used having a 3.5 dielectric constant and a thickness of 0.03 mm. The proposed massive MIMO antenna array resonates at two distinct frequencies i.e. 0.8195 and 1.4675 THz with a return loss of less than − 10 dB. Performance parameters like return loss, antenna gain, directivity, bandwidth, radiation pattern and VSWR are observed. With its greater directional gain of 25.6 dB and better directivity of 25.617 dB, the proposed 8 × 8 massive MIMO has a wider bandwidth of 66.7 GHz. In addition, the proposed array's radiation efficiency is 96%, its diversity gain is 9.9999 dB, its ECC is almost zero, its CCL is less than 25 bps/Hz, its TARC is less than − 10 dB, and its CC < 0.4 bps/Hz. The results gathered demonstrate that the proposed massive MIMO antenna array can be employed successfully for a wide range of terahertz applications due to its enhanced characteristics. [ABSTRACT FROM AUTHOR]

In this paper, a novel architecture of bidirectional underwater wireless optical communication (UWOC) system has been proposed to interconnect stationary and moving underwater sensor nodes for diverse applications. To achieve the bidirectional communication, wavelength division multiplexing (WDM) and remodulation approach have been used in this work. The proposed bidirectional UWOC system works at 40 Gbps data rate for both downlink (stationary node to moving node) and uplink (moving node to stationary node). Two distinct wavelengths of 532 nm and 531 nm have been used for uplink and downlink, the main attraction of the proposed architecture is that both the laser sources are placed at the stationary node. The moving node do not have any laser source and it remodulates the signal for sending data back to the stationary node. Because of this, the moving node contains lesser components which results in cost effectiveness, low power requirement and light weight. The proposed system successfully transmits the bidirectional information at a link range of 40 m under pure sea conditions in the presence of distinctive air bubble populations. The observed bit error rate (BER) values are 1.89 × 10− 13 and 1.19 × 10− 04 for the downlink and uplink respectively at a link range of 40 m, these BER values are under the acceptable forward error correction (FEC = 2 × 10− 3) limit. The proposed bidirectional UWOC system is beneficial for the development of a high-speed last-mile underwater solution. [ABSTRACT FROM AUTHOR]

A general framework for performance analysis of error probability over the fluctuating two ray (FTR) fading model with maximal ratio combining (MRC) receive diversity is presented in this paper. The probability density function (PDF) of FTR fading model with MRC is derived by using characteristic function method. Furthermore, the PDF approach is used to formulate the generalized average bit error rate (ABER) expression in closed-form. These generalized expressions are relevant for various modulation schemes for L branches of diversity receivers. The expressions of ABER for coherent modulation schemes with MRC diversity are derived by employing the tight, simple, and accurate approximation of the complementary error function. The calculated results are found to be close and accurate. The expressions of ABER for non-coherent modulation schemes with MRC diversity are calculated in exact closed-form. The validity of obtained expressions is verified with the special cases of FTR model exist in the literature. The main focus of the work is on how the MRC diversity elevates the reliability in communication by diminishing the channel fluctuations due to fading. [ABSTRACT FROM AUTHOR]

Ranging from optical fiber communication to optical wireless communication regimes, twisted light has drawn the prodigious contemplation of researchers. Thus far, the tricolor visible light laser diodes (TVL-LDs) have not been scrutinized for optical angular momentum (OAM), which, however, could pioneer fortuitousness towards a new paradigm of indoor wireless communication. Here, we proposed an OAM superposition of three different Laguerre Gaussian modes such as l = 0, m = 0; l = 14, m = 0; and l = 40, m = 0, and realised by utilising red, green and blue (R/G/B) LDs as independent channels and binary data streams are encoded incorporating non return to zero linecoding, exhibiting a total capacity of 45 Gbps (3 wavelengths (λ) × 3 OAM beams × 5 Gbps). The performance of R/G/B LDs is compared in a visible light communication (VLC) model at different input parameters such as link length between the irradiating source (Lambertian) and receiver detection region, transmitter half angle, incidence half angle, and optical concentrator area. We successfully performed the transmission of 45 Gbps data over a 1.4 m line of sight VLC link and 2.3 m in a non-LoS link employing TVL-LDs, while the red LDs offered excellent performance. [ABSTRACT FROM AUTHOR]

More and more, we may expect to see robots working side by side with humans as technology advances. Collaborative robot (cobot) is a methodology that investigates the cognitive and physical interaction between humans and robots as they work together to achieve a common goal. In the canon of cobot's writings, typically, one constructs a cognitive model that, among other things, takes in data about the users and the world and transforms them into data that the robot can use. It's only been relatively recently that we've begun to use machine learning to provide a cognitive framework and behavioral building block for high-quality human resource management. As a result, this study's purpose suggests a comprehensive literature analysis on machine learning's use of humans– Putting together robots to work together. A large number of publications were chosen for this analysis, and a grouping of works was performed based on the type. It proposes a paradigm of cognitive characteristics, evaluation measures, and collaborative tasks. After that, a comprehensive evaluation examines the features of several classes of machine learning, deep learning algorithms, and the sensing techniques employed; it is carried out. In addition to these realizations, the significance of machine learning techniques is emphasized—to account for temporal factors. When the key characteristics of these works are compared, patterns begin to emerge with the cobot and provide directions for future efforts, contrasting them with other parts of the cobot that have not been reviewed. [ABSTRACT FROM AUTHOR]

Hardware Trojan (HT) is a severe security threat during the development of an integrated circuit that can deviate the IC from its normal function and/or leak sensitive information during in-field operations. Trojans are often inserted during the fabrication phase, and to have Trojan-free ICs; it is highly desirable to detect them during post-silicon testing. Different test pattern generation-based HT detection techniques are reported in the literature to detect the Trojan during post-silicon testing. The existing methods provide low coverage and require a large number of test patterns. This paper proposes a new test pattern generation-based HT detection technique that provides high coverage while requiring less number of patterns. The proposed technique generates the optimal number of test patterns that activate the rare events by framing the problem as multi-objective optimization and solving it through a non-dominated sorting genetic algorithm (NSGA-II). The Trojans are mostly inserted using rare-triggered nodes (highly vulnerable, low controllable, and low observable). Thus, our technique applies the generated patterns during post-silicon testing to activate Trojans. Further, we also present the use of checker (detection) logic along with a proposed approach to effectively detect the Trojan during testing. The experimental evaluation on ISCAS benchmarks shows that the proposed technique provides 12 times higher trigger coverage with 1/3 fewer test patterns than the best-known existing genetic algorithm-based technique. [ABSTRACT FROM AUTHOR]

In this paper, the 50 Gbps next generation passive optical network stage 2 (50G- NGPON2) architecture is proposed via converging millimeter wave (MMWave) over fiber technology to meet the requirements of fifth generation (5G) fronthaul network such as enormous demand of high transmission rate and huge bandwidth. It uses the non-return to zero (NRZ) line code to generate pulse for 50 Gbps of data per channel, 28 GHz MMWave spectrum band over 60 km of bi-directional fiber span under the ITU-T G.9804 standardization. Two ideal erbium dopped fiber amplifiers (EDFA) with the gain of 10 dB and 5 dB respectively are used to amplify the signal on the transmitter side before transmission and receiver side after transmission. Outcomes of the proposed system demonstrate the network structure performance efficiency via Q-Factor (> 6), error rate, spectrums, and eye diagram. The variations of the Q-Factor for all optical network units (ONUs) during downstream and channels during upstream can be seen at the different fiber spans. Considering the scope of the future, in the area of digital processing, a single channel 50G-PON using 16-QAM is presented to improve the modulation and demodulation of MMWave spectrum. [ABSTRACT FROM AUTHOR]

This research reports the preparation and characterization of xanthan gum (XG)-based gel electrolytes (GEs) comprising sodium hydroxide salt (NaOH) in deionized water (DW). The three-dimensional gel network has been formed without using any synthetic polymer or cross-linking agents. Ionic conductivity of GEs was evaluated with different parameters, such as salt concentration, gum concentration, temperature and with the passage of time. The maximum ionic conductivity of 74.8 mS cm–1 was observed at room temperature even after 55 days for XG-based GE containing 0.625 M NaOH. A small change in pH values for XG-based GEs have been observed with temperature in the range of 10–70°C and at different time span. Thixotropic behaviour of GEs under the application of stress has also been analysed by rheological studies. There was no discernible change in ionic conductivity with temperature and with the passage of time, which make it desirable for their use in different device applications. [ABSTRACT FROM AUTHOR]

In future generation networks, data protection is a crucial necessity particularly when information is sent on a system. Network protection has three objectives known as discretion, reliability and accessibility. The most common procedure exploited to attain this ambition is encryption. The Generalized Multi Protocol Label Switched (GMPLS) optical networks are designed to survive Internet Protocol's (IPʹs) unreliable delivery. In this paper, GMPLS network is proposed with random users and then the data protection algorithms have been analyzed on proposed GMPLS optical network. The various algorithms involve Rivest Shamir Adleman (RSA) algorithm and Advanced Encryption Standard (AES) algorithm. The considered algorithms are very popular but have not been implemented on GMPLS optical networks in the literature which shows the novelty of the presented work. The network performance is compared for these algorithms in terms of various parameters like blocking probability and latency. The results reveal that RSA reduces the blocking probability < 0.005 and latency < 0.007 ms. This shows that RSA gives better performance than AES algorithm and enhance the quality of service considering blocking probability, latency and overheads in GMPLS optical networks leading to enhanced data protection. [ABSTRACT FROM AUTHOR]

Gum acacia (GA) based gel electrolyte was cross-linked with polyvinyl alcohol (PVA) in the presence of different concentrations of NaOH salt for the preparation of stable, biodegradable and saprophyte-free gel matrix, and characterized them with ionic conductivity, pH, FTIR and TGA studies. The maximum ionic conductivity (σ = 4.39 mS/cm at 30 °C) has been observed for GA-PVA based gel electrolyte containing lower concentration of NaOH salt and the analyte reaches toward neutral pH region as compared to acidic nature of gum acacia-based gel electrolyte in deionized water having ionic conductivity of 4.99 mS/cm at 30 °C. Physical cross-linking for better jellification has been analyzed through FTIR and thermogravimetric analysis (TGA). FTIR spectra of GA-PVA based gel electrolyte indicate the stability of the gel matrix at nearly neutral pH region and undergo complex decomposition with the influence of higher salt concentrations. Thermal stability and thermal behavior of gel electrolytes were investigated under non-isothermal conditions by thermogravimetric analysis and differential thermogravimetry (DTG), and the obtained results exhibit variations in the glass transition temperature (Tg) suggesting the miscibility of the compositions and also support the existence of compatibility of such system. Gel electrolyte with suitable composition indicates better stability near neutral pH region and small change in ionic conductivity over the temperature range of 10–70 °C make them suitable and applicable for many solid-state ionic device applications. [ABSTRACT FROM AUTHOR]

Hyperspectral images constitute a substantial amount of data in the form of spectral bands. This information is used for land cover analysis, specifically in classifying a hyperspectral pixel, which is a popular domain in remote sensing. This paper proposed an efficient framework to classify spectral-spatial hyperspectral images by employing multiobjective optimization. Spectral-spatial features of hyperspectral images are passed for optimization. As hyperspectral images have a high dimensional feature set, many classifiers cannot perform well. Multiobjective optimization reduces the feature set without affecting the discrimination ability of the classifier. The proposed work is validated on a standard hyperspectral image set, Pavia University and Kennedy Space Centre. [ABSTRACT FROM AUTHOR]

The next generation passive optical network stage 2 (NG-PON2) is a broadcast network in which a large number of optical network units (ONUs) can be served using various network topologies. In this paper, a purely passive remote node (RN) design based on fiber bragg grating (FBG) is presented for the bus topology of a high split NG-PON2 system. The performance of the proposed node has been analysed for a symmetric 80 Gbps NG-PON2 system serving 1024 ONUs in terms of bit error rate (BER) and optical signal to noise ratio (OSNR). The working of the proposed node has been explained with the optical frequency spectrums for downstream and upstream signals. The observed OSNR levels for the ONUs operating at the 1st RN is 84.8743 dB which decreases to 75.7973 dB for the ONUs connected to the 8th RN. The BER level < 10–9 for both upstream and downstream confirms the correct working of the proposed node in the NG-PON2 system. [ABSTRACT FROM AUTHOR]

In this paper, an accurate framework is proposed for deriving the closed-form expression for the average symbol error probability (ASEP) of generalized M-ary quadrature amplitude modulation (M-QAM) over the Beaulieu-Xie fading channel. This fading channel is extremely useful for characterizing heterogeneous networks, femtocells, and also for modeling of fading channel for high speed trains due to its ability to combine the properties of both Nakagami-m and Rician fading models. Due to efficient bandwidth and high data rate, the M-QAM modulation scheme is utilized for the 4G LTE, 5G network, etc. The closed-form expression for the ASEP of generalized M-QAM in terms of Gauss hypergeometric function is derived in this work. The advantage of this expression is that along with M-QAM, we can evaluate ASEP of many other modulation schemes such as binary phase shift keying (BPSK), quadrature phase shift keying (QPSK), etc. The numerical results are presented for the exact closed-form solution, which are a close match with Monte-Carlo simulations. To achieve ASEP of 10−3, 64-QAM requires 4.79 dB more average SNR as compared to 16-QAM for the case of m = 2, K = 1. [ABSTRACT FROM AUTHOR]

Security enhancement and bandwidth increase are requirements of ultrafast future optical code division networks that also minimise the latency at nodes without distressing the traffic performance. In OCDMA systems, eavesdropper tries to breach the optical code, and encoded/encrypted data in order to get correct code word of legitimate user. For security enhancement, an ultra high speed 4 × 100 Gbps two dimensional Diagonal identity matrix (2D-DIM) code and four input single output (FISO) all optical logic gate with private key encryption is proposed and its performance in terms of security is analyzed. Expressions for synchronous and asynchronous transmissions are derived for proposed work and it is perceived that asynchronous transmission has better security. Further performance/security analysis is carried out for different scenarios such as with/without FISO, with 1D-DIM/2D-DIM codes, using 4 × 1 AND gate/NOR gate in terms of correct code detection rate (CCDR), max. eye amplitude, Received Q factor, Signal to noise ratio at different launched power levels for legitimate user and eavesdropper. Eavesdropper attacked the proposed system but due to FISO layering, private key encryption, and 2D-DIM codes, cannot get acceptable level of CCDR. To the best of author's knowledge, proposed system is ultra high speed with enhanced security and no reported studies have investigated security enhancement at this much ultra high speed. [ABSTRACT FROM AUTHOR]

The present paper analyzes an L-branch maximal ratio combining (MRC) receiver over the Beaulieu-Xie (BX) fading channel. The expression of the probability density function (PDF) of the signal-to-noise ratio (SNR) of an MRC receiver in BX fading is derived by using the characteristic function approach. The obtained PDF is then utilized to calculate the various link-level and system-level parameters. This paper focuses on deriving closed-form expressions for different adaptive transmission techniques based on instantaneous channel state information in BX fading. The accuracy of our derived expressions is verified by comparing them with Monte Carlo simulations. [ABSTRACT FROM AUTHOR]

Classification of Hyperspectral images is mostly based on the spectral-spatial features in existing classification techniques. The captured Hyperspectral images from satellites may contain some noisy bands due to water absorption. The process of radiometric and atmospheric corrections leads to the removal of useful bands present in the acquired HSI. In this paper, a novel framework is proposed in which interpolation is used to accommodate the loss of noisy bands. Further, the extraction of hybrid features is performed using PCA and LPP to preserve spatial information, and these features are passed as input to the machine learning models. The proposed framework is compared with the existing spectral-spatial and spectral based frameworks by using the standard datasets-Indian Pines, Salinas, Pavia University, and Kennedy Space Centre. The accuracy of the classification is increased significantly when the proposed framework is blended with state-of-art classifiers. [ABSTRACT FROM AUTHOR]

Xanthan gum (XG)-based hydrogels containing sodium hydroxide (NaOH) salt were synthesized with the use of distilled water (DW) at room temperature and characterized through FTIR, TGA/DTG, and rheological studies. Sodium hydroxide is used to control pH toward neutral region along with improvement in ionic conductivity and stability of the electrolyte. The stabilized hydrogel has been obtained by applying heat treatment at ambient temperature for 5 wt% XG in 0.015 M solution of NaOH, which exhibits nearly neutral pH value at room temperature. The modification/shifting of the various peaks in FTIR spectra of xanthan gum with the addition of salt indicates the interaction or cross-linking between the constituents (xanthan gum, distilled water, and NaOH) and disappearing of peaks after heat treatment of the gel confirms its stability. DTG and TGA studies have been carried out to investigate thermal stability of these gels and illustrate the effect of heat treatment as a result of salt addition with thermogravimetric analysis up to 400 °C. However, rheological studies were performed for these hydrogels to analyze their viscosity behavior and mechanical stability. Along with the above characterization, gel sample (5 wt% XG in 0.015 M NaOH solution in DW) exhibits high ionic conductivity of 4.71 × 10−3 S/cm with 6.45 pH value at room temperature after heat treatment. These highly ion conducting, thermally and mechanically stable biodegradable xanthan gum-based hydrogels can also be used as an electrolyte for various device applications like supercapacitors, fuel cells, solar cells, etc. [ABSTRACT FROM AUTHOR]

Gel polymer electrolytes (GPEs) were prepared by dissolving lithium tetrafluoroborate (LiBF4) salt, poly(methylmethacrylate) (PMMA) polymer and distinct non-volatile solvents propylene carbonate (PC), and -N,N-dimethylformamide (DMF) in single as well as binary solvent mixtures. Ionic conductivities of 8.93 mS/cm and 6.68 mS/cm at 25 °C have been obtained for gel polymer electrolytes for 10 wt% PMMA in the solution of LiBF4 in binary solvent mixture of PC:DMF in (1:1) and (2:1) volume ratios respectively. The dispersion of nano-sized silica in gel polymer electrolyte not only exhibits small change in ionic conductivity but also enhances the mechanical strength as well as viscosity of gel polymer electrolytes. At room temperature, the ionic conductivity has been found to be 8.00 mS/cm for 6 wt% nano-sized silica in GPEs. Fourier-transform infrared (FTIR) spectroscopic studies have been used to scrutinize the corroboration of the complexation between PMMA, LiBF4, PC, DMF, PC:DMF, and SiO2. The interactions between salt and solvents in liquid electrolytes have also been analyzed by FTIR spectroscopy illustrating the strong interaction between lithium salt and solvent molecules. The appearance/disappearance and shifting of some peaks confirm the interaction among the constituents of nano-dispersed gel polymer electrolytes. The mechanical strength was confirmed by dynamic mechanical analysis (DMA) and viscosity [ηPC:DMF (2:1) > ηPC:DMF (1:1) > ηPC] for nano-dispersed silica-based gel polymer electrolytes. The electrical and mechanical stability with high ionic conductivity for such gel polymer electrolytes makes these electrolytes suitable for many device applications like high energy density lithium-ion batteries, super-capacitors, electro-chromic devices etc. [ABSTRACT FROM AUTHOR]

Classification techniques applicable to the hyperspectral images do not extract deep features from the hyperspectral image efficiently. In this work, a deep learning approach is proposed to extract the deep features, and these features are utilized to propose a novel framework for classification of the hyperspectral image. The framework uses LPP, DCNN and logistic regression. Data of a hyperspectral image is processed by LPP for dimensionality reduction as it contains a large number of dimensions. Afterward, a DCNN is constructed with Autoencoders which is then passed to the logistic regression for classification. Proposed framework is tested on Indian Pines and Salinas data sets. High accuracy is achieved using the proposed framework in comparison of existing machine learning models. [ABSTRACT FROM AUTHOR]

Nano-sized silica poly(methylmethacrylate)-based gel electrolyte containing lithium hexafluorophosphate (LiPF) was synthesized by using different binary solvent mixture (propylene carbonate(PC) and dimethylformamide (DMF) in different volume ratio). Role of DMF in PC: Higher DMF content in PC-based electrolyte shows higher ionic conductivity at all polymer content and at wide temperature regions (10-70 °C). A small increment in ionic conductivity at lower content of polymer in liquid/gel electrolyte was observed and having maximum conductivity of 13.12 mS/cm at 25 °C. Stability (mechanically and electrically), viscosity and ionic conductivity of gel electrolytes were improved with the addition of nano-sized silica at ambient temperature. Ionic conductivity of nano-sized silica-based gel electrolyte does not change much over 5-70 °C temperature range and is factor-wise only which make indispensable in different electrochemical devices. Also polymer gel electrolyte membranes as such and with dispersed silica nano-particles were characterized through scanning electron microscope to study the morphology of gel matrix. [ABSTRACT FROM AUTHOR]

Eqs. 21, 22, and 23 were incorrectly captured in the original manuscript. [ABSTRACT FROM AUTHOR]

We study hybrid optical amplifiers (HOAs) for dense wavelength division multiplexed (DWDM) systems at reduced channel spacing (<0.2 nm). The Raman erbium-doped fiber amplifier (EDFA) (R-E) and EDFA-semiconductor optical amplifier (SOA) (E-S) hybrid optical amplifiers (HOAs) are investigated for the first time at 0.05 and 0.1 nm of the channel spacing. We show that the R-E HOA provides better gain (23.9 dB) and induces lesser crosstalk (-14.1 dB) with minimum utilization of the bandwidth. We report that 70 km is the optimum span distance at which the R-E HOA achieves a 2450 km transmission distance with acceptable performance. The theoretical results are found to be in accordance with numerical simulations in terms of the amplifier gain and induced crosstalk. [ABSTRACT FROM AUTHOR]

In this paper, fractional Fourier transform based minimum mean squared error (MMSE) receiver is analyzed and compared with the time and frequency domain MMSE receivers in a multi-antenna environment. The distribution of SINR at the output of the receiver is used for calculating the bit error probability and the results are verified by comparison with the results obtained by Monte Carlo simulations. [ABSTRACT FROM AUTHOR]

Heart failure is the most common cause of morbidity and hospitalization in the western civilization. Protein phosphatases play a key role in the basal cardiac contractility and in the responses to β-adrenergic stimulation with type-1 phosphatase (PP-1) being major contributor. We propose here that formation of transient disulfide bridges in PP-1α might play a leading role in oxidative stress response. First, we established an optimized workflow, the so-called "cross-over-read" search method, for the identification of disulfide-linked species using permutated databases. By applying this method, we demonstrate the formation of unexpected transient disulfides in PP-1α to shelter against over-oxidation. This protection mechanism strongly depends on the fast response in the presence of reduced glutathione. Our work points out that the dimerization of PP-1α involving Cys39 and Cys127 is presumably important for the protection of PP-1α active surface in the absence of a substrate. We finally give insight into the electron transport from the PP-1α catalytic core to the surface. Our data suggest that the formation of transient disulfides might be a general mechanism of proteins to escape from irreversible cysteine oxidation and to prevent their complete inactivation. [ABSTRACT FROM AUTHOR]

Cathepsin S (CTSS) activity is elevated in Sjögren’s Syndrome (SS) patient tears. Here we tested whether protease inhibition and cystatin C (Cys C) levels are reduced in SS tears, which could lead to enhanced CTSS-driven degradation of tear proteins. CTSS activity against Cys C, LF and sIgA was tested in SS or healthy control tears. Tears from 156 female subjects (33, SS; 33, rheumatoid arthritis; 31, other autoimmune diseases; 35, non-autoimmune dry eye (DE); 24, healthy controls) were analyzed for CTSS activity and Cys C, LF, and sIgA levels. Cys C and LF showed enhanced degradation in SS tears supplemented with recombinant CTSS, but not supplemented healthy control tears. CTSS activity was significantly increased, while Cys C, LF and sIgA levels were significantly decreased, in SS tears compared to other groups. While tear CTSS activity remained the strongest discriminator of SS in autoimmune populations, combining LF and CTSS improved discrimination of SS beyond CTSS in DE patients. Reductions in Cys C and other endogenous proteases may enhance CTSS activity in SS tears. Tear CTSS activity is reconfirmed as a putative biomarker of SS in an independent patient cohort while combined LF and CTSS measurements may distinguish SS from DE patients. [ABSTRACT FROM AUTHOR]