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According to a recent study, adding intelligent reflecting surfaces (IRS) to propagation environments improves the performance of wireless devices. The capabilities of cognitive radio's spectrum sensing over environments with assisted wireless propagation via IRS are examined in this research. Taking channel fading effects into consideration, we derive closed-form analytical expressions for the average probability of detection (APD) for single user and cooperative users. Further, the derived APD expression is used to derive the average area under the receiver operating characteristics curve ( AUC ¯ ) expression. Monte Carlo simulations are also carried out in order to validate the derived expressions. Results demonstarte the extent of detectability performance in cognitive radio on utilizing the IRS aided wireless propagation environment therefore witnessing its significance for upcoming wireless technological advancement by offering spectrum efficiency with good quality of service (QoS). [ABSTRACT FROM AUTHOR]

We describe a screening protocol for making clinical decisions about the fading of protective equipment worn by children with intellectual disability (ID) who injure themselves. The Protective Equipment Screening Protocol includes information sources derived from research publications and is presented in a format conducive to review and completion by treatment teams. An accompanying case report illustrates protocoldriven protective equipment fading procedures implemented with a self-injurious student. Using the screening protocol in a clinical context and research directions are discussed. [ABSTRACT FROM AUTHOR]

Flower color is an important trait for the ornamental value of colored rapeseed (Brassica napus L.), as the plant is becoming more popular. However, the color fading of red petals of rapeseed is a problem for its utilization. Unfortunately, the mechanism for the process of color fading in rapeseed is unknown. In the current study, a red flower line, Zhehuhong, was used as plant material to analyze the alterations in its morphological and physiological characteristics, including pigment and phytohormone content, 2 d before flowering (T1), at flowering (T2), and 2 d after flowering (T3). Further, metabolomics and transcriptomics analyses were also performed to reveal the molecular regulation of petal fading. The results show that epidermal cells changed from spherical and tightly arranged to totally collapsed from T1 to T3, according to both paraffin section and scanning electron microscope observation. The pH value and all pigment content except flavonoids decreased significantly during petal fading. The anthocyanin content was reduced by 60.3% at T3 compared to T1. The content of three phytohormones, 1-aminocyclopropanecarboxylic acid, melatonin, and salicylic acid, increased significantly by 2.2, 1.1, and 30.3 times, respectively, from T1 to T3. However, auxin, abscisic acid, and jasmonic acid content decreased from T1 to T3. The result of metabolomics analysis shows that the content of six detected anthocyanin components (cyanidin, peonidin, pelargonidin, delphinidin, petunidin, and malvidin) and their derivatives mainly exhibited a decreasing trend, which was in accordance with the trend of decreasing anthocyanin. Transcriptomics analysis showed downregulation of genes involved in flavonol, flavonoid, and anthocyanin biosynthesis. Furthermore, genes regulating anthocyanin biosynthesis were preferentially expressed at early stages, indicating that the degradation of anthocyanin is the main issue during color fading. The corresponding gene-encoding phytohormone biosynthesis and signaling, JASMONATE-ZIM-DOMAIN PROTEIN, was deactivated to repress anthocyanin biosynthesis, resulting in fading petal color. The results clearly suggest that anthocyanin degradation and phytohormone regulation play essential roles in petal color fading in rapeseed, which is a useful insight for the breeding of colored rapeseed. [ABSTRACT FROM AUTHOR]

There are a growing number of publications supporting behavior-analytic strategies to increase compliance with medical procedures. However, little research has been conducted on the application of applied behavior analysis to teach compliance with and completion of the setup required for an overnight sleep study (polysomnography). The client in this report presented with autism, cerebral palsy, epilepsy, strokes, and severe destructive behavior (i.e., aggression, property destruction, self-injury). These conditions combined with a poor sleep/wake schedule and gasping during the night necessitated a sleep study. The caregiver referred their child to behavioral outpatient services due to medical noncompliance and severe destructive interfering behaviors with similar procedures (e.g., failed electroencephalogram [EEG]). We evaluated the effects of differential reinforcement without extinction and stimulus fading on compliance and reduction of destructive behavior with a 25-step sleep study procedure. Our approach successfully taught tolerance of the procedure and reduced destructive behavior. The client completed the scheduled sleep study and received a diagnosis of mild obstructive sleep apnea. [ABSTRACT FROM AUTHOR]

Difficulties in the localization of bodies of homicidal or drowning victims in natural water result in their submergence for weeks if not months. Water insects and microbes drastically change the body's appearance, which significantly changes the determination of a victim's identity. DNA analysis is commonly used for identifying the decedent; however, this PCR‐based approach is time‐consuming and destructive of the evidence. Considering that nearly half of the people in the world dye their hair with a variety of permanent and semi‐permanent dyes, one can expect that confirmatory identification of dyes on the body's hair can be used to shed light on the victim's identity. A growing body of evidence suggests that surface‐enhanced Raman spectroscopy (SERS) can be used to detect and identify hair dyes. In this study, we investigated the extent to which SERS could be used to detect black and blue, permanent and semi‐permanent dyes on hair submerged in hypolimnion water for up to twelve weeks. We found that SERS enabled 100% accurate identification of analyzed dyes on hair submerged in hypolimnion water for up to 8 weeks, whereas, on average, 87% accurate identification of the hair dyes could be achieved on hair exposed for 10 weeks and 50% for hair exposed 12 weeks in hypolimnion water. We also found that the aqueous environment caused progressive fading of some dyes, whereas other dyes showed substantial spectral transformations after prolonged submergence. Finally, we found that changes in the intensity of vibrational bands of dyes could be used to predict the duration of submergence of colored hair in hypolimnion water. [ABSTRACT FROM AUTHOR]

Non-orthogonal multiple access (NOMA) is an emerging multiple access technique for future generation wireless networks. Owing to the wide applicability of NOMA, precise expressions for the outage performance under various fading conditions are very much needed. The literature on the outage analysis of NOMA systems is extensive. However, a unified approach is required to test the outage performance of NOMA under various impairments as well as fading scenarios. Hence, in this paper we provide a unique procedure to evaluate the outage probability of downlink-NOMA and preciseness in the derived expressions is achieved by including error in channel state information and successive interference cancellation (SIC), intra- and inter-cell interference. The outage probability is derived over (i) homogeneous fading channels: Rayleigh and Nakagami-m faded distributions with and without log-normal shadowing, Rician fading, and (ii) non-homogeneous fading channels: α - μ , η - μ , α - η - μ , κ - μ and α - κ - μ shadowed distributions. The numerical results are evaluated by varying different fading parameters, error in channel estimation and SIC, and number of interferers. The impact of shadowing on the outage performance of NOMA is also analyzed. The obtained analytical results are validated with simulated results. [ABSTRACT FROM AUTHOR]

A networked control system is an enhanced version of a control system that works in tandem with two independent technologies, viz. communication and control. One of the major concerns in using wireless channels for measurement and control data transfer is packet drops. These packet drops can be correlated in time when considering a more realistic channel condition such as fading. The goal of this study is to develop a state estimation algorithm and optimal control strategy for networked control systems in the presence of correlated packet drops, determine bounds on estimation error covariance and validate the results through simulations using a specific mobile robot model. [ABSTRACT FROM AUTHOR]

PADC is well known as a highly sensitive solid-state nuclear track detector. A proposal is for a radiation education method that utilizes these characteristics. A significant issue in the proposed educational method using PADC is the time-consuming etching process. This study attempted to reduce etching time by using a homemade PADC. The experimental results have revealed that the homemade PADC achieves faster etch pit enlargement compared to BARYOTRAK (commercial PADC). An attempt was made to enlarge etch pit diameters rapidly by irradiating UV at a wavelength of 253.7 nm and etching with NaOHaq/ethanol solution. The results revealed that UV irradiation at a wavelength of 253.7 nm, after etching, resulted in etch pit diameters several times larger than those obtained in conventional methods within the same etching time. Therefore, UV irradiation and short-time etching with NaOHaq/ethanol solution proved to be effective. This study also investigated the effects of fading on the PADC during its storage period after UV irradiation. The experimental results confirmed that the etch pit diameters shrank by approximately 30% after 2 months of storage. However, considering the enlargement effect of the etch pit diameters due to UV irradiation, it can be concluded that UV irradiation is practical for radiation education experiments. [ABSTRACT FROM AUTHOR]

The capacity for a treatment to maintain its effects over time may be the most critical component of behavioral interventions for challenging behavior as treatments that fail to persist are likely to be of little value to society. We reviewed the quality and quantity of different types of post‐intervention data for the treatment of challenging behavior in studies published over the last 7 years. We found that for the majority of participants at least one measure of maintenance, fading, or follow‐up was reported but with limited information regarding the quality of those measures. Reports of secondary variables related to post‐intervention data (e.g., latency to measurement) were also uncommon. We discuss possible explanations for the paucity of post‐intervention data, barriers to obtaining post‐intervention data, strategies for obtaining these data, and implications for the external validity of behavioral interventions for challenging behavior. We provide recommendations for increasing the probability that post‐intervention data are included in applied research on challenging behavior. [ABSTRACT FROM AUTHOR]

Generalized mutual information (GMI) is used to compute achievable rates for fading channels with various types of channel state information at the transmitter (CSIT) and receiver (CSIR). The GMI is based on variations of auxiliary channel models with additive white Gaussian noise (AWGN) and circularly-symmetric complex Gaussian inputs. One variation uses reverse channel models with minimum mean square error (MMSE) estimates that give the largest rates but are challenging to optimize. A second variation uses forward channel models with linear MMSE estimates that are easier to optimize. Both model classes are applied to channels where the receiver is unaware of the CSIT and for which adaptive codewords achieve capacity. The forward model inputs are chosen as linear functions of the adaptive codeword's entries to simplify the analysis. For scalar channels, the maximum GMI is then achieved by a conventional codebook, where the amplitude and phase of each channel symbol are modified based on the CSIT. The GMI increases by partitioning the channel output alphabet and using a different auxiliary model for each partition subset. The partitioning also helps to determine the capacity scaling at high and low signal-to-noise ratios. A class of power control policies is described for partial CSIR, including a MMSE policy for full CSIT. Several examples of fading channels with AWGN illustrate the theory, focusing on on-off fading and Rayleigh fading. The capacity results generalize to block fading channels with in-block feedback, including capacity expressions in terms of mutual and directed information. [ABSTRACT FROM AUTHOR]

Technological advancements, barging economics quest for swift communication. The growing demand for data rate and network coverage has pursued telecommunication companies to expand and upgrade their network for maximum coverage and agile speed. The Long Term Evolution (LTE) networks are based on a homogenous configuration comprised of Macrocells. However, during peak hours these macro base stations respond to few numbers of clients whereas many of the user's requests remain unresponded since these stations lack adequate capacity to tolerate the load of increased traffic on the network. To avoid congestion homogeneous networks are turned into heterogeneous networks by augmenting macro base stations with Low Power Nodes (LPN) using femto, pico, and microcells. We propose a new call handling algorithm in which cells are deployed in a hierarchical manner where the priority of originating calls is given to femtocell. The proposed algorithm was implemented for a realistic scenario in a teaching institution and the performance was assessed and compared for 4 scenarios using 3 user cases. Results show that there is a significant improvement in the number of connections established and throughput for both indoor and outdoor users when we increase LPN for a certain critical area. During peak hours, in the fading environment, there is only a 50% connectivity ratio in presence of a single macrocell for 200 users. After applying our algorithm, the connectivity boosts up to 80% which is further increased by deploying more LPNs. Over a well-organized network, the proposed scheme attested to be more efficient than those formerly used, subsequently contributing satisfying outcomes for the end-users. [ABSTRACT FROM AUTHOR]

Hyperspectral imaging has emerged as a promising analytical method of artwork due to its potential in combining non-invasive analytical capabilities and imaging allowing the survey of the entire (or of a large area of the) surface of an artwork, which is a highly significant application for historic tapestries. This project deployed a high-resolution ClydeHSI Art Scanner, which was used with both a push-broom visible to very-near infrared (VNIR; 400–1000 nm) and near infrared (NIR; 900–1700 nm) hyperspectral cameras. Initial testing focused on the characterisation and mapping of the different materials used on historic tapestries (wool, silk, metal threads). To facilitate the dye characterisation, a collection of wool and silk samples dyed with recipes based on medieval practices was used. The samples measured using the system and the data collected formed an external reference library including the type of the natural dyes and mordants used during their production. The outcomes of the on-site deployment of this analytical instrumentation for the characterisation and analysis of 16th century tapestries on display at Hampton Court Palace will be discussed. [ABSTRACT FROM AUTHOR]

This research studies the problem of a joint capacity/capacity reliability analysis of the multiuser multi-input multioutput (MIMO) system functioning in the presence of generalized multipath fading. The study presents the derived results of the closed-form analytical statistical description of the ergodic sum-rate capacity, the capacity reliability and the capacity's higher-order statistics in the case of complex Nakagami-m distributed channel transmission coefficients. A numerical verification of the derived expressions was performed, and it demonstrated excellent correspondence with the simulation. The system performance was evaluated with the help of a numerical analysis of the joint first- and second-order statistics description, depending on the channel and system parameters. The results demonstrated several peculiarities, e.g., the existence of a specific extremum of the capacity reliability for small-sized MIMO systems, its opposite behavior (in terms of the varying number of antenna elements) for heavy and light fading, and the existing asymptotic regions of the system and the channel parameters. [ABSTRACT FROM AUTHOR]

In recent years, anthocyanins, natural dyes, have promoted great scientific and technological interest. Their intrinsic antioxidant properties and health benefits make them ideal representatives of natural dyes as replacements for synthetic dyes. However, their instability can limit their use. A promising strategy to increase the color stability of anthocyanins is their interaction with clay minerals structures. Clay minerals have characteristics favorable to the stabilization of natural dyes, such as adsorption capacity, good surface chemistry, ion exchange capacity, abundance, non-toxicity, and environmental compatibility. This review summarizes relevant works that present different clays or clay minerals as robust inorganic matrices for incorporation, improved stability, and increased resistance against the thermal- and photodegradation of anthocyanins. In addition, several authors propose different applications for the formed anthocyanin-based hybrids. [ABSTRACT FROM AUTHOR]

Background: Optically stimulated luminescence (OSL) dosimeters produce a signal linear to the dose, which fades with time due to the spontaneous recombination of energetically unstable electron/hole traps. When used for radiotherapy (RT) applications, fading affects the signal-to-dose conversion and causes an error in the final dose measurement. Moreover, the signal fading depends to some extent on treatment-specific irradiation conditions such as irradiation times. Purpose: In this work, a dose calibration function for a novel OSL film dosimeter was derived accounting for signal fading. The proposed calibration allows to perform dosimetry evaluation for different RT treatment regimes. Methods: A novel BaFBr:Eu2+-based OSL film (Zeff, 6 MV = 4.7) was irradiated on a TrueBeam STx using a 6 MV beam with setup:01 gantry angle, 90 cm SSD, 10 cm depth, 10 × 10 cm2 field. A total of 86 measurements were acquired for dose-rates (D1) of 600, 300, and 200 MU/min for irradiation times (tir) of 0.2, 1, 2, 4.5, 12, and 23 min and various readout times (tscan) between 4 and 1440 min from the start of the exposure (beam-on time). The OSL signal, S(D1, tir, tscan), wasmodeled via robust nonlinear regression, and two different power-law fading models were tested, respectively, independent (linear model) and dependent on the specific tir (delivery-dependent model). Results: After 1 day from the exposure, the error on the dose measurement can be as high as 48% if a fading correction is not considered. The fading contribution was characterized by two accurate models with adjusted-R2 of 0.99. The difference between the two models is <4.75% for all tir and tscan. For different beam-on times, 3, 10.5, and 20 min, the optimum tscan was calculated in order to achieve a signal-to-dose conversion with a model-related error <1%. In the case of a 3 min irradiation, this condition is already met when the OSLfilm is scanned immediately after the end of the irradiation. For an irradiation of 10.5 and 20 min, the minimum scanning time to achieve this model-related error increases, respectively, to 30 and 90 min. Under these conditions, the linear model can be used for the signal-to-dose conversion as an approximation of the delivery-dependent model. The signal-to-dose function, D(Mi,j,tscan), has a residual mean error of 0.016, which gives a residual dose uncertainty of 0.5 mGy in the region of steep signal fading (i.e.,tscan = 4 min). The function of two variables is representable as a dose surface depending on the signal (Mi, j) measured for each i, j-pixel and the time of scan (tscan). Conclusions: The calibration of a novel OSL-film usable for dosimetry in different RT treatments was corrected for its signal fading with two different models.A linear calibration model independent from the treatment-specific irradiation condition results in a model-related error <1% if a proper scanning time is used for each irradiation length. This model is more practical than the delivery-dependent model because it does not need a pixel-to-pixel fading correction for different tir. [ABSTRACT FROM AUTHOR]

The brake system is the most significant active safety system that converts the vehicle's mechanical energy into heat energy based on the braking pair's friction. The transfer of heat in the brake pair during braking occurs by conduction, convection, and radiation. In disc brakes, which are widely used today, the effect of the heat transfer coefficient, which continually changes with the disc's angular velocity on the cooling of the braking pairs is important. The change in heat convection coefficient can be calculated with a numerical approach. In this study, on disc temperature effect of heat convection coefficient and angular velocity has been examined with the finite element method using the experimental data in the SAE J2522 Comprehensive Brake Efficiency Test Standard, fading test procedure. Disc brake design has been designed in the SOLIDWORKS program, and analysis has been carried out using ANSYS 2020 R2 in steady-state thermal analysis. It has been determined that the cooling amounts at the initial of braking are higher than the cooling amounts at the end of braking, and the effect of cooling by convection in the reduction of the temperature difference at the end of braking compared to the initial state is between 91.22% and 91.74%. [ABSTRACT FROM AUTHOR]

The use of mmWaves for achieving 5G networks is increasingly being seen as a necessity due to the vastly improved bandwidth and data rates at these frequencies. These waves suffer from severe attenuation and their use may, however, be restricted, in the immediate future, to short-range networks, such as personal area networks (IEEE 802.11ad) or vehicular and mobile adhoc networks operating in proximity. MmWaves require directional antennas which have the added advantage of allowing spatial reuse. Even though the high gain in a given direction in such antennas allows us to extend the range, there are several factors, such as error in antenna orientation, fading, blockage which show that an optimum beamwidth can be obtained to maximize the network throughput. The treatment of transmissions, during Line-of-Sight transmission conditions and during Non-Line-of-Sight, is completely different. The paper has evaluated the optimum beamwidth for successful mmWave transmissions in mmWave adhoc networks at 60 Ghz in short-range mmWave networks (IEEE 802.11ad). [ABSTRACT FROM AUTHOR]

The utilization of denim dates back to ancient times, and still, it is one of the most utilized fabrics around the globe. Special considerations are given to its fading effects. There are many ways for the said fading associated with pros and cons. The laser fading process is a competitive alternative compared to the conventional physical and chemical methods used for getting the aged and worn look on denim fabrics concerning environmental load. This paper critically reviews the laser-based fading of denim fabrics, its effect on physical, mechanical properties, and fading as it influences the material's appearance, comfort, and life. Furthermore, the key features of laser fading, the influence of various laser parameters on the final physio-mechanical properties, and color fading of denim have been discussed in detail with the recent literature. Laser fading is a more sustainable and green choice. [ABSTRACT FROM AUTHOR]

CaB4O7 nanoparticles doped with different concentrations of Dy3+ were prepared by using solution combustion method. The recorded Thermoluminescence (TL) and Optically stimulated luminescence (OSL) of CaB4O7:Dy samples for different concentrations of Dy3+ irradiated with 6 Gy of X-Ray shows concentration quenching effect above 0.05 at.wt% of Dy3+ concentrations. The TL and OSL kinetic parameters of glow curves were evaluated using "tgcd" and conventional fitting methods. The TL glow curve of the CTB:(0.05%)Dy have five individual glow peaks with maximum peak temperatures at 410, 470, 525, 563 and 593 K. TL Dose response of the X-Ray irradiated CTB:(0.05%)Dy is also found to be linear in the range of 1 Gy to 50 Gy. The OSL glow curves of the CTB:Dy nanoparticles follow non-first order kinetics and can be fitted with the sum of three first order decay curves. Fading characteristics of the TL and OSL signals are studied for 40 days and found to be very stable. [ABSTRACT FROM AUTHOR]

Daylight fluorescent pigments with their intense color effects have attracted great interest among artists since their market launch in the mid-twentieth century. Since then they have been widely used in the visual arts. The pigments are mainly compositions of organic fluorescent dyes and optical brighteners diluted in an insoluble resin. Due to the susceptibility of the dyes to visible and UV radiation, their lightfastness is comparatively low. This paper presents a comprehensive study of the color and fluorescence changes of daylight fluorescent paints upon exposure in visible light and ultraviolet radiation conducted on mock-ups of commercial daylight fluorescent pigments. The different aging characteristics of the pigments depend on the color tone. They were recorded by means of photographic and colorimetric documentation. In addition, Raman spectroscopy was used to identify the main dyes of the various pigments, even in the complex system of paints, consisting of primer, binder, resin and dyes, and to determine their degradation during aging. Fluorescence spectroscopy revealed that the change in fluorescent color may not only be due to the decrease in dye concentration, but also to the transformation of the original dyes into other fluorescent compounds during light aging. Finally, this paper provides recommendations for the presentation of artworks containing daylight fluorescent pigments. [ABSTRACT FROM AUTHOR]

Several information-theoretic studies on channels with output quantization have identified the capacity-achieving input distributions for different fading channels with 1-bit in-phase and quadrature (I/Q) output quantization. However, an exact characterization of the capacity-achieving input distribution for channels with multi-bit phase quantization has not been provided. In this paper, we consider four different channel models with multi-bit phase quantization at the output and identify the optimal input distribution for each channel model. We first consider a complex Gaussian channel with $b$ -bit phase-quantized output and prove that the capacity-achieving distribution is a rotated $2^{b}$ -phase shift keying (PSK). The analysis is then extended to multiple fading scenarios. We show that the optimality of rotated $2^{b}$ -PSK continues to hold under noncoherent fast fading Rician channels with $b$ -bit phase quantization when line-of-sight (LoS) is present. When channel state information (CSI) is available at the receiver, we identify $\frac {2\pi }{2^{b}}$ -symmetry and constant amplitude as the necessary and sufficient conditions for the ergodic capacity-achieving input distribution; which a $2^{b}$ -PSK satisfies. Finally, an optimum power control scheme is presented which achieves ergodic capacity when CSI is also available at the transmitter. [ABSTRACT FROM AUTHOR]

This work examined the thermoluminescence dosimetry characteristics of Ag-doped ZnO thin films. The hydrothermal method was employed to synthesize Ag-doped ZnO thin films with variant molarity of Ag (0, 0.5, 1.0, 3.0, and 5.0 mol%). The structure, morphology, and optical characteristics were investigated using X-ray diffraction (XRD), scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDX), photoluminescence (PL), and UV–vis spectrophotometers. The thermoluminescence characteristics were examined by exposing the samples to X-ray radiation. It was obtained that the highest TL intensity for Ag-doped ZnO thin films appeared to correspond to 0.5 mol% of Ag, when the films were exposed to X-ray radiation. The results further showed that the glow curve has a single peak at 240–325 °C, with its maximum at 270 °C, which corresponded to the heating rate of 5 °C/s. The results of the annealing procedures showed the best TL response was found at 400 °C and 30 min. The dose–response revealed a good linear up to 4 Gy. The proposed sensitivity was 1.8 times higher than the TLD 100 chips. The thermal fading was recorded at 8% for 1 Gy and 20% for 4 Gy in the first hour. After 45 days of irradiation, the signal loss was recorded at 32% and 40% for the cases of 1 Gy and 4 Gy, respectively. The obtained optical fading results confirmed that all samples' stored signals were affected by the exposure to sunlight, which decreased up to 70% after 6 h. This new dosimeter exhibits good properties for radiation measurement, given its overgrowth (in terms of the glow curve) within 30 s (similar to the TLD 100 case), simple annealing procedure, and high sensitivity (two times that of the TLD 100). [ABSTRACT FROM AUTHOR]

Orthogonal frequency division multiplexing (OFDM), one of the most dominant technology for fifth-generation (5G) wireless communication systems offers a high data rate with better spectrum efficiency. However, OFDM based systems suffer from various channel imperfections such as channel distortion, carrier frequency offset (CFO) due to transceiver local oscillator frequency mismatch, sampling frequency offset (SFO) between DAC/ADCs, nonlinear distortion (NLD) due to the nonlinear power amplifier, and fading caused by frequency selective channels. Recently OFDM based non-orthogonal multiple access (NOMA) scheme is attracting researchers' attraction owing to its high spectral efficiency, massive connectivity, and resilience to frequency selectivity for the upcoming 5G wireless communication and beyond. However, NOMA-OFDM systems suffer the same demerits as OFDM-based systems to deploy such a multicarrier system for 5G and beyond applications. This paper studies the problem of various channel imperfections on OFDM and OFDM-NOMA systems and proposes machine learning (ML) based estimation and signal detection for OFDM and NOMA-OFDM based systems in presence of the aforementioned channel imperfections. Various ML models like neural network (NN), Recurrent-NN, long-short-term-memory are adopted in this research for channel estimation-equalization, CFO-SFO estimation and compensation and mitigation of NLD in OFDM and NOMA-OFDM receiver. Extensive simulation studies show that the ML-based techniques outperform traditional LS, MMSE-based methods for OFDM receiver, and LS-SIC, MMSE-SIC based methods for NOMA-OFDM receiver. [ABSTRACT FROM AUTHOR]

During recovery phases following a nuclear or radiological incident, it is crucial to assess the radiation exposure of both the general public and responders. This assessment is vital for directing protective actions and for conducting subsequent analyses of the incident's impact. Several methods have been employed at different timescales after an incident, including assessments based on measurements of materials present at the time of the incident. Common salt has previously been shown to have potential for retrospective dosimetry in the μGy-mGy dose range using portable OSL instruments. This study aims to explore the effects of sample storage under light and dark conditions on OSL signals. The OSL signals indicate a brief decrease in luminescence during the initial days after irradiation, followed by a gradual rise with extended storage. The period from 8 days to 64 days is characterized by relatively stable results, which encompass a significant portion of the timeframe relevant for dose estimation during both the early and later phases of responding to radiological emergencies. Light exposure (simulated daylight) results in an extremely rapid loss of OSL signals. Results are discussed with reference to TL measurements of associated trapping systems which provide insight into potential zeroing mechanisms and the observed fading behaviour. The results are sufficiently favourable to conclude that these characteristics, together with the widespread availability and low cost of household salt, support its use for prompt emergency assessment and as a retrospective dosimeter, below 100 μGy. • Optically stimulated luminescence (OSL) of sodium chloride (NaCl) was studied as emergency OSL dosimeters. • NaCl has a strong radiation-induced OSL signal. • Salt is highly sensitive to optical bleaching. • Requires light and humidity proof covering for dosimeters in the field. • Two peaks at T max = 110 °C unstable (1.47h), at T max = 284 °C stable for emergency dosimetry. [ABSTRACT FROM AUTHOR]

The main drawback of LiMgPO 4 is high fading. In order to improve the time stability of the optically stimulated luminescence (OSL) signal of LiMgPO 4 after irradiation, five preparation processes had been adopted to prepare five kinds of LiMgPO 4 :Er phosphor. The structure of the prepared samples was analyzed by X-ray diffraction. The OSL decay curves, thermoluminescence (TL) glow curves, OSL sensitivity, minimum detectable dose (MDD) and the fading properties after irradiation for the five kinds of LiMgPO 4 :Er phosphors were investigated. Considering minimizing fading 24 h after irradiation, the preparation process for samples heated at 900 °C for 10 h is optimal. The OSL fading of LiMgPO 4 phosphor is improved significantly by changing the preparation processes. The less than 5% loss of the OSL signal was measured after 24 h of the irradiation for samples heated at 900 °C for 10 h when the integration time is more than 0.5 s, and the sensitivity by taking the total area under the OSL curve of this samples is about half that of TLD-500k. There is a loss of less than or equal to 5% of the OSL signal for samples heated at 900 °C for 10 h when the integration time is greater than or equal to 20 s within 30 days after irradiation. LiMgPO 4 :Er samples heated at 900 °C for 10 h is the LiMgPO 4 phosphor with the lowest fading so far. It is possible to prepare a LiMgPO 4 phosphor with a low fading after irradiation and a moderate sensitivity by further investigating the preparation processes. • Considering minimizing fading, the preparation process for samples heated at 900 °C for 10 h is optimal. • Less than or equal to 5% of the OSL signal can be gotten within 30 days after irradiation. • The sensitivity is about half that of TLD-500k. [ABSTRACT FROM AUTHOR]

This article presents a study of high-energy X-ray dosimetry carried out at CEA Gramat. In this study, we are interested in alumina as a new thermoluminescent dosimeter. We performed several pre-irradiation protocols to use alpha-alumina as a dosimeter over doses ranging from 0.09 Gy to 350/400 Gy in order to obtain calibration curve for these different protocols. [ABSTRACT FROM AUTHOR]

Summary: The moment generating function (MGF)‐based approach is found as more profound as compared with probability density function (PDF)‐based counterpart for error rate analysis in any communication system. However, it fails in the case of several modulation schemes with constellation size M, such as M‐PSK, M‐QAM, and M‐PAM schemes among the others, due to the computational complexity of the involved integration. Though authors in the literature suggest alternate analytical expressions to overcome the problem it is solved only for M‐PSK and M‐QAM schemes. Hence, we present a generic MGF‐based tight approximation for the error rate analysis of different modulation schemes. Particularly, error rate analysis of M‐PAM, M‐AM, B‐PSK, B‐FSK, and orthogonal B‐FSK with non‐coherent (Non‐Co) detection modulation schemes are presented through known MGF based expressions without the evaluation of any integration. Also, a simple analytical expression for the M‐QAM modulation scheme is presented. Besides, the proposed MGF‐based analytical expressions are used to evaluate the error rate of M‐PSK, M‐PAM, and M‐AM modulation schemes over the generalized‐K (GK) fading channel, which is not presented in literature due to the computational complexity of involved integration. Newly, derived analytical expressions are validated through Monte Carlo simulation. The graphical results show the validity and accuracy of the proposed unified MGF‐based analytical expressions for error rate analysis of different modulation schemes over kμ‐gamma and GK fading channels, respectively. [ABSTRACT FROM AUTHOR]

Both sequencing content and fading instructional support are scaffolding techniques designed to make it easier for learners to process information. While sequencing content separates problems into manageable parts before problem-solving, fading of instruction gradually reduces instructional support before problem-solving. Although cognitive load research generally supports the notion that both of these techniques minimise extraneous processing, some research shows that they contribute to an increase in cognitive load under certain circumstances. This study seeks to bridge the gap in the research by examining the relationships that both techniques have with extraneous cognitive load. The results obtained through survey analysis of university students taking online courses show that sequencing content and fading instruction over the course of a semester had a negative relationship with extraneous load. These results are explained against the backdrop of conflicting research, and recommendations are presented to reduce extraneous processing within the learning environment. [ABSTRACT FROM AUTHOR]

We analyze the impact of arbitrary dependence between the forward and backward links in backscatter communication systems. Specifically, we quantify the effect of positive and negative dependence between these fading links on channel capacity by using Copula theory. The benefits of this approach are highlighted over the classical framework of linear dependence based on Pearson’s correlation coefficient, which is also analyzed. Results show that for a fixed transmit power budget, capacity grows with positive dependence as well as with fading severity in the low signal-to-noise ratio (SNR) regime. Conversely, fading dependence becomes immaterial in the high SNR regime. [ABSTRACT FROM AUTHOR]

Multiple antennas are usually employed to improve the performance of the wireless communication system. To this context, we derive the effective capacity (EC) expressions for Inverse Gamma (I-Gamma) shadowed fading channel, employing maximal ratio combining (MRC) and selection combining (SC) diversity schemes at the receiver (Rx) side. The channels are assumed to be independent and identical distributed (i.i.d.). In addition to this, we also propose the simplified high-power approximation that enables direct interpretation of the system performance concerning system fading parameters. Furthermore, to diminish the effect of shadowing over composite statistics, macroscopic diversity analysis is presented as an application, where Weibull, and I-Gamma models are used to obtain composite statistics. At last, we validate our proposed formulations through the Monte-Carlo simulation. [ABSTRACT FROM AUTHOR]

Kinetic analysis of the thermoluminescent (TL) glow curve of aquamarine, a cyan variety of beryl (Be 3 Al 2 (SiO 3) 6), is reported. Samples were irradiated at room temperature using a90Sr/90Y β source at a rate of 0.10 Gy-1. Measurements made at 1 °C/s after irradiation from 1 to 100 Gy show a high intensity peak at 75 °C followed by three secondary peaks at 115, 189 and 302 °C respectively. The dose response of the high intensity peak (called the main peak) is linear within the first 20 Gy, but tends towards sub-linearity as the dose is close to 100 Gy. The signal decays with the time delay between irradiation and reading. It decays about 14% of its initial value, 600 s after irradiation. Reproducibility analysis shows that the material reproduces its response under identical experimental conditions with an uncertainty of 0.8% after 10 Gy beta dose irradiation. The kinetic analysis of the TL glow curve was carried out using the curve fitting method. The results show that the main peak follows first order kinetics, its activation energy is of the order of 1 eV and the frequency factor is between 1012 and 1014 s−1, while some secondary peaks follow general order kinetics. [Display omitted] • Kinetic analysis of the TL glow curve of aquamarine is reported. • The TL glow curve consists of four peaks located at 75, 115, 189, and 302 °C. • The main peak (75 °C) follows first order kinetics. Its activation energy is ∼1 eV. • Aquamarine shows a linear response with dose from 1 Gy to 20 Gy. • The curve shows a thermal fading ∼14% of its initial value 600 s post irradiation. [ABSTRACT FROM AUTHOR]

Mobile communications systems are affected by what is known as fading, which is a well-known problem largely studied for decades. The direct consequence of fading is the complete loss of signal (or a large decrease of the received power). Rayleigh fading is a reasonable model for wireless channels although, Nakagami-m distribution seems better suited to fitting experimental data. In this paper we obtain the Nakagami-m distribution as a composite (mixture) of the Rayleigh distribution, a result which as far as we know it has not been shown in the literature. This representation of the Nakagami-m distribution facilitates computations of the average BER (Bit Error Rate) for DPSK (Differential Phase Shift Keying) and MSK (Minimum-Shift Keying) modulations for this distribution and higher moments of them, which is of great applicability to modeling wireless fading channels. Furthermore, a simple, not depending on any special function, apart of the Gamma function, bivariate version of the Nakagami-m distribution is also proposed as a special case of the multivariate version which is also presented. The proposed composite distribution is simulated through the standard procedure of summation of phasors, and results for the new closed-form measures for the MSK modulation are also shown. From that it is clear that the alternative formulation of the Nakagami-m distribution allows for easier modeling of fading fading-shadowing wireless channels through the new explicit second order statistics metrics. is well suited for modelling fading-shadowing wireless channels. [ABSTRACT FROM AUTHOR]

SrSO 4 nanoparticles doped with different concentrations of Eu were synthesised by using co-precipitation method and annealed at 500 °C, 700 °C and 900 °C respectively. The prepared SrSO 4 :Eu nanophosphors shows highly crystalline orthorhombic structure with crystallite size of about 30 nm as observed from the X-ray diffraction (XRD) pattern. TEM (Transmission Electron Microscopy) analysis confirms the particle size to be around 40 nm for the synthesised nanophosphors. Energy Dispersive X-ray (EDX) spectrum showed the presence of only Eu dopant without any other impurity into the SrSO 4 sample. The thermoluminescence (TL) glow curve of 1 Gy of gamma ray irradiated SrSO4:Eu measured at heating rates 1 K/s has a well-defined single peak at around 468 K. The TL kinetic parameters for the synthesised nanoparticles evaluated using initial rise method, peak shape method, Booth method and deconvolution method were all in agreement and found to be activation energy (E), order of kinetics (b) and frequency factors (s). • SrSO 4 :Eu nanoparticles were synthesised by using co-precipitation method. • SrSO 4 :Eu with 0.5 at.wt.% annealed at 900 °C exibits the most highest intensity. • Dose response plot of the prepared sample is linear in the range of 0.5 Gy–500 Gy. • Deconvolution of the TL glow curve of SrSO 4 :Eu shows a single and isolated glow peak. [ABSTRACT FROM AUTHOR]

We analyze the symbol error probability (SEP) of $M$ -ary pulse amplitude modulation ($M$ -PAM) receivers equipped with optimal low-resolution quantizers. We first show that the optimum detector can be reduced to a simple decision rule. Using this simplification, an exact SEP expression for quantized $M$ -PAM receivers is obtained when Nakagami- $m$ fading channel is considered. The derived expression enables the optimization of the quantizer and/or constellation under the minimum SEP criterion. Our analysis of optimal quantization for equidistant $M$ -PAM receiver reveals the existence of error floor which decays at a double exponential rate with increasing quantization bits, $b$. Moreover, by also allowing the transmitter to optimize the constellation based on the statistics of the fading channel, we prove that the error floor can be eliminated but at a lower decay exponent than the unquantized case. Characterization of this decay exponent is provided in this paper. We also expose the outage performance limitations of SEP-optimal uniform quantizers. To be more precise, its decay exponent does not improve with $b$. Lastly, we demonstrate that the decay exponent of a quantized receiver can be complemented by receive antenna diversity techniques. [ABSTRACT FROM AUTHOR]

Carrier frequency offset (CFO) and channel estimation is a classic topic with a large body of prior work using the maximum likelihood (ML) approach together with the Cramér-Rao lower bound (CRLB) analysis. We give the maximum a posteriori probability (MAP) estimation solution, which is particularly useful for tracking. Unlike the ML cases, the corresponding Bayesian CRLB (BCRLB) shows a clear relation with parameters and low complexity algorithms are provided to achieve the BCRLB in almost all SNR range. Among them, the universal algorithm takes a new approach and avoids error floors of the traditional approach. We assume that the time invariant MIMO channel within a packet can have spatial correlation and nonzero mean. The estimation is based on pilot signals. An unexpected result is that the joint MAP estimation is equivalent to an individual MAP estimation of the frequency offset first, again different from the ML results. We provide insight on the pilot/training signal design based on the BCRLB. Unlike past algorithms that trade performance and/or complexity for the accommodation of time varying channels, the MAP solution provides a different route for dealing with time variation. Within a short enough (segment of) packet where the channel and CFO are approximately time invariant, the low complexity algorithm can be employed. Similar to the belief propagation, the estimation of the previous (segment of) packet can serve as the prior knowledge for the next (segment of) packet. [ABSTRACT FROM AUTHOR]

Efficient spectrum utilisation with massive connectivity among devices is a primary motivation for the upcoming technologies. As current static spectrum allocation policies cannot meet such requirement, a millimetre band communication along with cognitive radio enabled devices can be thought of as a promising solution to achieve such requirements. This paper investigates the performance of cognitive radio spectrum sensing over the millimetre band communication channel employing various diversity reception techniques. Fluctuating two ray (FTR) fading model have been utilised to characterise the millimetre band fading communication channel, as different from other conventional available stochastic channel models FTR fading model yields better fit at millimetre frequency band, incorporates a family of conventional fading channels, and can be used to model worse than Rayleigh fading scenarios. Novel analytic expressions for average detection probability ( POD ¯ ) and average area under the receiver operating characteristics ( AUC ¯ ) corresponds to maximal-ratio combining (MRC), selection combining (SC), and square-law selection (SLS) diversity reception are derived which are subsequently used to derive detection probabilities for cooperative spectrum sensing (CSS). To this end, a generalized closed-form expression for end to end statistics of instantaneous signal to noise ratio (SNR) for SC diversity operating over FTR fading channel is also derived. Obtained expressions are used to examine ED performance over various fading scenarios and at different time-bandwidth products including the case of inaccurate threshold estimation. Presented outcomes quantify the severity of fading on detection performance and effect of noise in to threshold decision further a comparative analysis between different diversity reception techniques provides a useful insight for cognitive radio deployments at different channel environments. In the end Monte Carlo simulation have been provided for the validation of obtained theoretical results. [ABSTRACT FROM AUTHOR]

In this article, we analyze the bit error rate (BER) performance of the multiple-input multiple-output (MIMO) based free-space optical (FSO) link by adopting Gamma–Gamma (GG) distribution with atmospheric turbulences (ATs) and pointing errors (PEs). By expanding the GG distribution, the complexity is high due to Meijer-G function with MIMO. To reduce the complexity, we proposed a mathematically tractable power series based probability density function of the GG fading with PEs and ATs. Based on the proposed power series PDF, the exact BER is derived, allowing to analyze the BER performance for single-input single-output (SISO), Single Input Multiple Output (SIMO) and extended to MIMO link for three combining schemes with M-ary Phase Shift Keying (M-PSK). The derived BER expression also helps to derive the Asymptotic Bit Error Rate (ABER), diversity gain, combining gain and cross-validated for SISO, SIMO and MIMO/FSO links. The effect of PEs over the performance of the FSO link is analyzed and observed that PEs degrades the BER and gain of the FSO link rapidly. The deduced MRC provides high SNR gain at-least 3.5 dB over EGC and 8 dB gain over SC for negligible PEs ξ = 11.23 at BER 10−6 and for BER 10−3, the SNR gain for MRC over EGC is 1.5 dB and approximately above 3 dB over SC for severe PEs ξ = 1.23. The proposed power series based PDF offers high gain and power efficiency of the MIMO/FSO link over SISO and SIMO link. This article identifies the crucial factors affecting the FSO link and helps in mitigating them to design an optimal system and opens for wide range of applications like fifth-generation (5G) networks, smart city applications etc. [ABSTRACT FROM AUTHOR]

The book Asrar al-Tawhid is a mystical work in which social agents are represented in different ways. The purpose of the present study is to analyze the discourse of this book based on Van Leeuwen's model relying on the descriptive-analytical method. Preliminary results of the study indicate that in this work, Abu Saeed Abu al-Khair is introduced as a dynamic and effective force through activation. The highest frequency of writing after Abu Saeed Abu al- Khair is related to Khajeh Hassan Modab, the special agent of Abu Saeed and Abolghasem Qashiri. It is obvious that the frequency of naming this prestigious figure due to his final inclination towards Abu Sa'id has had a tremendous impact on the image and spiritual legitimacy of Abu Sa'id Abu al-Khair. In Asrar al-Tawhid, the highest frequency of groups is related to Sufi elders, dervishes, and disciples, all of whom belong to their own group and to the sect-oriented discourse. In the non-identification section, it was found that the identities of anonymous agents were not important in propagating the method-oriented discourse. However, what matters is what they do. The actions of these anonymous agents always have a similar and effective function in expressing the author’s mystical views, which often include observing and perceiving the greatness and importance of the spiritual personality of Abu Sa'id Abu al-Khair. In the book Asrar al-Tawhid, the humanization of animals has an ideological burden, because the presence of these wild animals is one of the virtues of Abu Sa'id Abu al-Khair to be a sign of his legitimacy, consolidation of power, and truth. From the point of view of the deletion component, it was proved that parts of Abu Sa'id's knowledge include the category of fading, since the producer of discourse in this work, like other seekers, is obliged to refrain from revealing the secrets of God and not to share the secret of truth except with the people of truth. [ABSTRACT FROM AUTHOR]

The artificial neural network (ANN) is an information processing technology inspired by the information processing technique of the human brain. The way the simple biological nervous system works is imitated with ANN. In this study, an ANN model is proposed to analyze and simulate TL intensity of experimental data of quartz crystals with respect to the fading. In this model, network type and transfer function are chosen as the feed-forward backpropagation algorithm and Tansig respectively for the training of the proposed ANN model. The optimization process is also chosen as Levenberg–Marquardt in this study. The performance criteria of the proposed method were evaluated according to the coefficient of determination (R2) and mean-squared error (MSE) techniques. After simulation results are obtained, the TL glow curve of the prediction results of quartz crystal is obtained as a function of fading time irradiated with β-source at 70 Gy for stored in 64 h at room temperature. [ABSTRACT FROM AUTHOR]

This paper proposes a novel cooperative spectrum sensing network (CSSN) with improved energy detector (IED) based cognitive radio (CR) users. Every CR user is furnished with multiple antennas (M) and performs itself selection combining (SC) operation. All the CRs sense a primary user (PU) via erroneous sensing channels (S) and send the data to a fusion center (FC) via erroneous reporting channels (R). At FC, decision about PU is evaluated with the assistance of k-out-of-N rule. Detection probability expressions for a CR and FC subject to noise plus Rayleigh/Rician fading are developed. Also both simulation and analytical frameworks for throughput analysis are presented. The analytical performance results are also validated using simulation performance results. Performance comparisons between IED and conventional energy detectors (CED) are presented in terms of throughput and total error rate for several parameter values. Further, overall performance of throughput and total error rate in Rayleigh/Rician fading channels is investigated. The joint effects of diversity and fading on the CSSN throughput is also additionally discussed. Channel error (r) impact on the throughput and total error performances for each proposed and traditional networks is studied. Optimization of several parameters for maximizing the throughput and minimizing the total error is also studied. Throughput overall performance of proposed CSSN is plenty better than the conventional network in each fading channel. For several values of M and r, p opt , λ n , opt and N opt values are calculated subject to each fading environment. Both analytical and MATLAB simulation results are matched. Under imperfect channel conditions, performances in terms of throughput and total error are not up to the mark but significant performance improvement has been obtained with diversity at each CR level. [ABSTRACT FROM AUTHOR]

In the communication process of Unmanned Aerial Vehicle (UAV), it will be affected by interference, resulting in performance degradation. In order to better understand its communication performance, the channel can be simulated. Firstly, this study analyzed the characteristics of UAV communication channel, described the large-scale fading, small-scale fading and interference of signals, introduced the channel modeling method, analyzed the calculation method of model parameters, and finally carried out simulation experiments. The results showed that the simulation results of the channel were basically similar to the actual results. In addition, from the perspective of anti-electromagnetic interference performance, the larger the interference to signal ratio was, the greater the symbol error rate of the channel was. The experimental results verifies the reliability of channel simulation, which can provide a good theoretical basis for UAV communication research. The channel simulation is worth further application and promotion. [ABSTRACT FROM AUTHOR]

Passive solid state dosimeters, such as thermoluminescence dosimeters, provide integrated measurement of the total dose and are widely used in environmental monitoring programs. The objective of this paper is to provide a comprehensive review on the use of thermoluminescent dosimetry methods for monitoring radiation dose in the environment. The article presents the part of the research results of the project PREPAREDNESS (EMPIR 2016 call for Metrology for Environment joint research project) with a particular objective to harmonize procedures used by dosimetry services, relevant authorities and Institutes across the Europe. To achieve this, different monitoring routines that are based on passive environmental dosimetry methods are investigated. Differences in performing specific steps such as preheating, reading, annealing, minimizing fading, and others, are analyzed. The investigation was performed by means of qualitative literature review that showed the lack of information about specific steps. The conclusion of this work is that thermoluminescent dosimetry measurement system has to be type-tested even though the testing procedure is complicated. In addition to this, control dosimeters should be introduced, International Organization for Standardization protocols should be followed during calibration, and finally, parameters influencing the measurement uncertainty have to be identified and well understood in order to produce accurate dose measurement results. [ABSTRACT FROM AUTHOR]

Aubusson (France) has been inscribed on the List of Intangible Cultural Heritage of Humanity by UNESCO since 2009 for its centuries‐old tradition for the art of tapestry. The present study concerns one of these "Grand teint" tapestries, a Verdure with Count von Brühl's coat of arms (18th C.), characterized by very high‐quality dyeing and fine weaving. The restoration in progress allowed the removal of the lining of the back, which protected the colour from light. Hyperspectral imagery and μ‐spectrofluorimetry made on each side of the tapestry showed the influence of natural degradation of dyes. Experimental tests carried out model samples artificially aged, allowed us a better understanding of these observations. The fibers (silk and wool) and dyes (weld, ...) were identified and the roles of alum and tartar as mordants were questioned. Our work revealed the action of the recipe on the photodegradation rate and the effect of aging on the spectra's shape for yellow dyes and the disappearance of some compounds, such as chlorophyll "a," as a marker of the degradation. [ABSTRACT FROM AUTHOR]

In this work, a non-orthogonal multiple access (NOMA) based transmission between a source and two end users is examined over slow Generalized-K distributed (GKD) fading channels, where a single relay using decode-and-forward (DF) protocol is selected out of a set of full-duplex/half-duplex (FD/HD) multiple relays with the quality of service requirements. Two stage relay selection (RS), selecting a relay out of a set of relays providing service quality for user 1 to maximize data rate of user 2, is analyzed. Additionally, not only perfect successive interference cancellation (pSIC) but also imperfect SIC (ipSIC) is considered. Self-interference (SI) and ipSIC are assumed to be Nakagami-m distributed, additionally, Gaussian and channel gain dependent modelling of ipSIC are also considered. A new expression for cumulative distribution function (CDF) of GKD is provided, thereafter, robust approximated probability density function (PDF) and CDF for GKD based on generalized Gauss-Laguerre quadrature are derived. Since outage probability (OP) analysis with exact CDF is found to be unstable, approximated and asymptotic OP expressions are derived and validated via Monte Carlo simulation technique. Approximated CDF, in turn OP, expression is almost excellent. Unlike existing works, our expressions are unique and valid for all cases such as FD and HD together with pSIC and ipSIC, i.e. expressions are not given separately but in a single compact form. Effects of SI, ipSIC, fading and shadowing parameters on OP are demonstrated and it is also shown that RS can significantly reduce OP. Finally, nonzero diversity order is asserted and details are provided. [ABSTRACT FROM AUTHOR]

Summary: Cognitive radio (CR) is an advanced technique used for the utilization of radio spectrum. A CR node uses the radio spectrum of a licensed user (called as primary user, PU) deviously. In this work, a cooperative sensing network (CSN) with improved energy detection (IED)‐based CR nodes is proposed. Each CR node consists of multiple antennas and perform themselves selection diversity (SC) technique. Each CR node senses a PU through erroneous sensing channel and reports its sensing data (1‐bit binary‐decision) to the fusion center (FC) through erroneous reporting channels. At FC, existence of PU (presence or absence) is identified using k‐out‐of‐N fusion rule. The novel expressions for detection probability over noise plus Nakagami‐q/n fading channels are derived and the mathematical frameworks for analysis of throughput and energy‐efficiency of the proposed network are developed. The simulation testbed is also developed and presented in this work to validate the analytically obtained performance characteristics. For several network parameters values, the investigation on comparison between IED and traditional energy detection method for various decision fusion rules is studied. Further, performance characteristics are analytically illustrated for throughput and energy‐efficiency over noise plus Nakagami‐q/n fading channels. The impact of diversity technique and effect of fading severity parameters on the throughput and energy‐efficiency are also investigated. The effect of channel error on total error performance for both proposed and conventional networks is shown. Finally, optimal fusion rule and optimal network parameters values correspond to maximum throughput and maximum energy‐efficiency are also identified. [ABSTRACT FROM AUTHOR]

The Thannhauser Collection of the Solomon R. Guggenheim Museum, New York, represents an important survey of European avant-garde art production during the late 19th and early 20th centuries. Among the works included in this collection are three paintings by Vincent van Gogh, namely Roadway with Underpass (1887), Landscape with Snow (1888), and Mountains at Saint-Rémy (1889). These examples each exhibit some degree of surface alteration, including fading of specific pigments and, in one case, a non-original, discolored varnish, resulting in obscured color and spatial relationships, as well as being the subject of questions regarding authenticity in the case of the two earlier pictures. Initial examination involved documentation of the brushwork, paint quality, and distribution of colors under magnification. Infrared (IR) and ultraviolet (UV) photography, as well as X-radiography, provided additional information on the surface coatings, the structure of the works, and their supports. Subsequently, an in-depth scientific investigation of the ground and paint layers, with a special focus on fading colors and altered surfaces, was carried out non-invasively with point and macro-X-ray fluorescence (XRF) spectroscopy, visible reflection spectroscopy, and multi-channel visible spectrum four-light imaging, followed by the analysis of cross sections and dispersed pigment samples by means of optical microscopy, transmission Fourier-transform infrared (FTIR) and Raman spectroscopies, and scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM/EDS), as well as high-performance liquid chromatography with photodiode array detection (HPLC-PDA) and pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). Results indicated that both the brushwork and artist's palette of all three paintings are consistent with data previously reported for other Van Gogh works and with pigments described in the artist's letters to his friends and his brother Theo. Most notably, evidence of biodeterioration and paint alteration phenomena was found on Roadway with Underpass, while specific pigments such as eosin red—historically sold as geranium lake—were detected in areas of Landscape with Snow and Mountains at Saint-Rémy that display severe fading. In addition to assisting the development of a suitable plan for the conservation of the 1887 painting, this study traces the progression of Van Gogh's practice over three years critical to his artistic development, discusses the historical context in which each masterpiece was created, identifies the range of materials and techniques used, and addresses authenticity questions by providing a comparison with results of scientific analysis from other similar works. [ABSTRACT FROM AUTHOR]

Hybrid RF/FSO systems have gained significant attention recently as a reliable approach to enhancing wireless data transmission rates. Intelligent selection between RF and FSO links, driven by the switching mechanism and diversity, plays a pivotal role in ascertaining the quality of the connection. This process, hinged upon a predefined threshold, significantly influences link quality determination. However, conventional methods for determining the switching rely on extensive numerical simulation leading to abrupt switching. To address this issue, this paper introduces an innovative relay-assisted multi-link hybrid switching mechanism that combines RF/FSO technologies. Notably, the proposed mechanism integrates a link-quality aware strategy to attain an optimal threshold level, thereby addressing the aforementioned problem effectively. The proposed mechanism utilizes an evolutionary seagull-based link quality-aware switching scheme to minimize bit error rates while maximizing capacity, considering the outage probability of both RF and FSO systems. The proposed methodology enhances the overall quality of links by introducing an intermediate decode-and-forward relay and multiple connections. Several criteria, including as outage probability, bit error rate, and ergodic capacity, are used to evaluate this improvement. A comparative analysis is conducted to evaluate the performance of the proposed approach in contrast to existing FSO systems. The findings highlight the promising capabilities of the relay-assisted hybrid RF/FSO system, showcasing its ability to significantly improve the quality of connections. This research contributes to advancing hybrid RF/FSO systems and their applicability in scenarios where atmospheric conditions, pointing errors, and fading effects influence link quality. • Nakagami-m and Malaga distributions characterize RF and FSO channels while accounting for key transmission losses, including turbulence, misalignment errors, and fading. • Developed closed-form expressions for BER, outage probability, and channel capacity to analyze relay-assisted hybrid RF/FSO systems under turbulence, pointing errors, and RF fading. • Proposed an efficient multi-objective evolutionary-based switching scheme to optimize threshold values while considering BER and capacity trade-offs. • Improved relay protocol by conditioning data transfer on relay node. [ABSTRACT FROM AUTHOR]

This paper examines the detection challenges faced by the cognitive radio network in the scenario where the node position of the secondary user changes rapidly, hence causing a significant amount of large-scale fading. To analyze this we have adopted a natural generalization of the fluctuating two-ray fading (FTR) channel that takes into account the simultaneous effects of both small and large-scale fading. Hence, in this direction, we have presented a composite fading model where small-scale fading is characterized as FTR distributed and large-scale fading as inverse gamma distributed. We derive exact analytical closed-form expressions for the composite probability distribution function (PDF) and cumulative distribution function (CDF) and then obtain a set of new statistical results. These results are further extended to obtain the analytical expressions for (i) Single user detection probability (ii) multi-user detection probability and (iii) average area under the receiver operating characteristic for energy detection-based spectrum sensing. A thorough investigation of the derived expression is used to quantify the degree of deterioration observed in the detection performance due to large-scale fading effects and the extent of performance benefit obtained by exploiting the cooperative spectrum sensing technique under different scenarios. The validity of the derived expressions is verified by Monte-Carlo simulations. [ABSTRACT FROM AUTHOR]

Direct-Sequence Code Division Multiple Access (DS-CDMA) is a digital method to spread spectrum modulation for digital signal transmission. We propose to detect signal in DS-CDMA communication using the learning mechanism. Initially, the user signals are spread using the respective pseudo-noise (PN) code where the input signal is multiplied with the code which is then modulated using the quadrature phase shift keying (QPSK) modulator. The modulated signal is then transmitted in a 3G/4G channel considering all types of fading. The transmitted signal is received by the antenna array which is performed by demodulation. We propose to adaptively assign the weights by employing Improved Whale Optimized Multi-Layer Perceptron Neural Network (IWMLP-NN)-based learning mechanism. To design IWMLP-NN, Improved Whale Optimization Algorithm is combined with multilayer perceptron neural network. This is used instead of the normal Multiple Signal Classification (MUSIC) and least mean squares (LMS)/root-mean-square (RMS) algorithms used in beam-forming networks. After assigning weight through IWMLP-NN-based learning mechanism, we de-spread to get the original user data. We have compared our proposed technique with the normal techniques with the help of plots of Bit Error Rate (BER) versus Signal-to-Noise Ratio (SNR). We use both the AWGN channel and fading channel for analysis. Experimental results prove that our proposed method achieves better BER performance results even with deep fading. [ABSTRACT FROM AUTHOR]