92 research outputs found

    Impact of mechanical vibration on over-the-air link at upper mmW frequencies

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    Abstract. Mechanical vibrations will affect the performance of the wireless link especially with coming 6G systems, which will operate at significantly higher frequencies than current 5G networks. The mechanical vibrations affect the frequency generation circuitries of the radio equipment and thus the performance of the radio link. The amount mechanical vibration to the radio or any equipment has been standardized and a short summary of related standards has been given in the thesis. Some practical measurements have been performed to verify the effects of mechanical vibration on wireless link performance. The measurement has been done with a vector signal analyzer that measures the S-parameters of the wireless link. The phase response of the measured S-parameters has been studied to illustrate the phenomena. The mechanical vibration has been measured with a mobile phone application which detects the changes, vibrations, and location changes of the mobile phone when it was placed over the frequency extender. As a result of the selection of frequency extenders, the RF measurement equipment has been able to perform over a greater frequency range than was originally intended. The used mobile phone application was the G-force meter, which is freely available from application stores. The measured S-parameters S11 and S21 were analyzed with Matlab software which was provided for the purpose. The measured S-parameters and vibration results have been time synchronized in the Matlab result post-processing. The measurement results show clearly that mechanical vibrations influence the radio signal phase and thus it needs to be considered in the future development of 6G

    Null Steering of Adaptive Beamforming Using Linear Constraint Minimum Variance Assisted by Particle Swarm Optimization, Dynamic Mutated Artificial Immune System, and Gravitational Search Algorithm

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    Linear constraint minimum variance (LCMV) is one of the adaptive beamforming techniques that is commonly applied to cancel interfering signals and steer or produce a strong beam to the desired signal through its computed weight vectors. However, weights computed by LCMV usually are not able to form the radiation beam towards the target user precisely and not good enough to reduce the interference by placing null at the interference sources. It is difficult to improve and optimize the LCMV beamforming technique through conventional empirical approach. To provide a solution to this problem, artificial intelligence (AI) technique is explored in order to enhance the LCMV beamforming ability. In this paper, particle swarm optimization (PSO), dynamic mutated artificial immune system (DM-AIS), and gravitational search algorithm (GSA) are incorporated into the existing LCMV technique in order to improve the weights of LCMV. The simulation result demonstrates that received signal to interference and noise ratio (SINR) of target user can be significantly improved by the integration of PSO, DM-AIS, and GSA in LCMV through the suppression of interference in undesired direction. Furthermore, the proposed GSA can be applied as a more effective technique in LCMV beamforming optimization as compared to the PSO technique. The algorithms were implemented using Matlab program

    Functional Assessment of the Medicago truncatula

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    The Medicago truncatula NIP/LATD (for Numerous Infections and Polyphenolics/Lateral root-organ Defective) gene encodes a protein found in a clade of nitrate transporters within the large NRT1(PTR) family that also encodes transporters of dipeptides and tripeptides, dicarboxylates, auxin, and abscisic acid. Of the NRT1(PTR) members known to transport nitrate, most are low-affinity transporters. Here, we show that M. truncatula nip/latd mutants are more defective in their lateral root responses to nitrate provided at low (250 μm) concentrations than at higher (5 mm) concentrations; however, nitrate uptake experiments showed no discernible differences in uptake in the mutants. Heterologous expression experiments showed that MtNIP/LATD encodes a nitrate transporter: expression in Xenopus laevis oocytes conferred upon the oocytes the ability to take up nitrate from the medium with high affinity, and expression of MtNIP/LATD in an Arabidopsis chl1(nrt1.1) mutant rescued the chlorate susceptibility phenotype. X. laevis oocytes expressing mutant Mtnip-1 and Mtlatd were unable to take up nitrate from the medium, but oocytes expressing the less severe Mtnip-3 allele were proficient in nitrate transport. M. truncatula nip/latd mutants have pleiotropic defects in nodulation and root architecture. Expression of the Arabidopsis NRT1.1 gene in mutant Mtnip-1 roots partially rescued Mtnip-1 for root architecture defects but not for nodulation defects. This suggests that the spectrum of activities inherent in AtNRT1.1 is different from that possessed by MtNIP/LATD, but it could also reflect stability differences of each protein in M. truncatula. Collectively, the data show that MtNIP/LATD is a high-affinity nitrate transporter and suggest that it could have another function

    BIRDS-1 CubeSat Constellation using Compact UHF Patch Antenna

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    BIRDS-1 satellites, a constellation of five identical 1U CubeSats, were designed, manufactured, assembled, integrated, and tested at LASINE Laboratory, Kyutech, Japan. Students from five nations (Japan, Ghana, Mongolia, Nigeria, and Bangladesh) collaborated to develop a number of CubeSats with coordinated ground coverage, named “Joint Global Multi-Nation BIRDS,” or abbreviated as “BIRDS.” To establish the downlink communication between satellite and Earth, an UHF patch antenna was utilized. Patch antennas offer an ideal solution to Cube satellite communication requirements due to their compact dimension and lightweight. However, the limited surface area available in CubeSats, conventional UHF and VHF patch antennas cannot be used. In this paper, a compact coaxial fed UHF (437.375 MHz) patch antenna system for 1U BIRDS-1 CubeSat (small satellite) is presented. The proposed antenna consists of a spiral meander line patch at the top side and partial ground plane another side of the substrate. A shorting pin has also been utilized to change the resonance to the required UHF band. For the intended 1U BIRDS-1 application, the goal is to mount on satellite body within a limited area of 1U BIRDS-1 satellite. The proposed antenna dimension (0.105λ×0.047λ×0.002λ at 437.375 MHz) and characteristics are compatible with any CubeSat standard structure. A prototype of the antenna was developed with a 1.57-mm-thick single layer Roger\u27s substrate having a relative permittivity of 2.2, and measured results are consistent with simulation. The proposed UHF antenna has integrated and tested with 1U BIRDS-1 satellite. Finally, the satellite was successfully launched on June 3, 2017, from the John F. Kennedy Space Center, the USA at Low Earth Orbit for earth observations, message relay, space environment, and technology demonstration through the International Space Station

    From Traditional Breeding to Genome Editing for Boosting Productivity of the Ancient Grain Tef Eragrostis tef (Zucc.) Trotter

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    Tef (Eragrostis tef (Zucc.) Trotter) is a staple food crop for 70 of the Ethiopian population and is currently cultivated in several countries for grain and forage production. It is one of the most nutritious grains, and is also more resilient to marginal soil and climate conditions than major cereals such as maize, wheat and rice. However, tef is an extremely low-yielding crop, mainly due to lodging, which is when stalks fall on the ground irreversibly, and prolonged drought during the growing season. Climate change is triggering several biotic and abiotic stresses which are expected to cause severe food shortages in the foreseeable future. This has necessitated an alternative and robust approach in order to improve resilience to diverse types of stresses and increase crop yields. Traditional breeding has been extensively implemented to develop crop varieties with traits of interest, although the technique has several limitations. Currently, genome editing technologies are receiving increased interest among plant biologists as a means of improving key agronomic traits. In this review, the potential application of clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated proteins (CRISPR-Cas) technology in improving stress resilience in tef is discussed. Several putative abiotic stress-resilient genes of the related monocot plant species have been discussed and proposed as target genes for editing in tef through the CRISPR-Cas system. This is expected to improve stress resilience and boost productivity, thereby ensuring food and nutrition security in the region where it is needed the most

    Allelic differences in Medicago truncatula NIP/LATD mutants correlate with their encoded proteins’ transport activities in planta

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    This article examines the hypothesis that MtNIP/LATD may have another biochemical activity

    Natural language processing based advanced method of unnecessary video detection

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    In this study we have described the process of identifying unnecessary video using an advanced combined method of natural language processing and machine learning. The system also includes a framework that contains analytics databases and which helps to find statistical accuracy and can detect, accept or reject unnecessary and unethical video content. In our video detection system, we extract text data from video content in two steps, first from video to MPEG-1 audio layer 3 (MP3) and then from MP3 to WAV format. We have used the text part of natural language processing to analyze and prepare the data set. We use both Naive Bayes and logistic regression classification algorithms in this detection system to determine the best accuracy for our system. In our research, our video MP4 data has converted to plain text data using the python advance library function. This brief study discusses the identification of unauthorized, unsocial, unnecessary, unfinished, and malicious videos when using oral video record data. By analyzing our data sets through this advanced model, we can decide which videos should be accepted or rejected for the further actions

    Microwave breast imaging using compressed sensing approach of iteratively corrected delay multiply and sum beamforming

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    Microwave imaging (MI) is a consistent health monitoring technique that can play a vital role in diagnosing anomalies in the breast. The reliability of biomedical imaging diagnosis is substantially dependent on the imaging algorithm. Widely used delay and sum (DAS)-based diagnosis algorithms suffer from some significant drawbacks. The delay multiply and sum (DMAS) is an improved method and has benefits over DAS in terms of greater contrast and better resolution. However, the main drawback of DMAS is its excessive computational complexity. This paper presents a compressed sensing (CS) approach of iteratively corrected DMAS (CS-ICDMAS) beamforming that reduces the channel calculation and computation time while maintaining image quality. The array setup for acquiring data comprised 16 Vivaldi antennas with a bandwidth of 2.70-11.20 GHz. The power of all the channels was calculated and low power channels were eliminated based on the compression factor. The algorithm involves data-independent techniques that eliminate multiple reflections. This can generate results similar to the uncompressed variants in a significantly lower time which is essential for real-time applications. This paper also investigates the experimental data that prove the enhanced performance of the algorithm. 2021 by the authors. Licensee MDPI, Basel, Switzerland.Acknowledgments: This work was supported by Grant NPRP12S-0227-190164 from the Qatar National Research Fund, a member of Qatar Foundation, Doha, Qatar and the internal grant of Qatar University QUST-1-CENG-2021-6 and the claims made herein are solely the responsibility of the authors. This work was supported by the Ministry of Higher Education of Malaysia (MOHE), grant code No. FRGS/1/2018/TK04/UKM/01/3. This work was supported by Grant NPRP12S-0227-190164 from the Qatar National Research Fund, a member of Qatar Foundation, Doha, Qatar and the claims made herein are solely the responsibility of the authors. Open Access funding provided by the Qatar National Library.Scopu

    Functional Assessment of the Medicago truncatula NIP/LATD Protein Demonstrates That It Is a High-Affinity Nitrate Transporter

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    Article on the functional assessment of the Medicago truncatula NIP/LATD protein demonstrating that it is a high-affinity nitrate transporter
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