3,520 research outputs found

    Meta-learning applications for machine-type wireless communications

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    Abstract. Machine Type Communication (MTC) emerged as a key enabling technology for 5G wireless networks and beyond towards the 6G networks. MTC provides two service modes. Massive MTC (mMTC) provides connectivity to a huge number of users. Ultra-Reliable Low Latency Communication (URLLC) achieves stringent reliability and latency requirements to enable industrial and interactive applications. Recently, data-driven learning-based approaches have been proposed to optimize the operation of various MTC applications and allow for obtaining the desired strict performance metrics. In our work, we propose implementing meta-learning alongside other deep-learning models in MTC applications. First, we analyze the model-agnostic meta-learning algorithm (MAML) and its convergence for regression and reinforcement learning (RL) problems. Then, we discuss uncrewed aerial vehicles (UAVs) trajectory planning as a case study in mMTC and RL, illustrating the system model and the main challenges. Hence, we propose the MAML-RL formulation to solve the UAV path learning problem. Moreover, we address the MAML-based few-pilot demodulation problem in massive IoT deployments. Finally, we extend the problem to include the interference cancellation with Non-Orthogonal Multiple Access (NOMA) as a paradigm shift towards non-orthogonal communication thanks to its potential to scale well in massive deployments. We propose a novel, data-driven, meta-learning-aided NOMA uplink model that minimizes the channel estimation overhead and does not require perfect channel knowledge. Unlike conventional deep learning successive interference cancellation (SICNet), Meta-Learning aided SIC (meta-SICNet) can share experiences across different devices, facilitating learning for new incoming devices while reducing training over- head. Our results show the superiority of MAML performance in addressing many problems compared to other deep learning schemes. The simulations also prove that MAML can successfully solve the few-pilot demodulation problem and achieve better performance in terms of symbol error rates (SERs) and convergence latency. Moreover, the analysis confirms that the proposed meta-SICNet outperforms classical SIC and conventional SICNet as it can achieve a lower SER with fewer pilots

    Spectral studies of some hydroxy-derivatives of anthraquinones

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    The u.v., visible, and i.r. spectra of several hydroxy-anthraquinones are discussed and the bands are assigned. These bands are compared with those of anthracene and anthraquinone. The band at 207 nm. is assigned to a n-sigma* transition; the bands at 252, 272, and 326 nm. are assigned by measuring spectra in solvents of various polarities. The stability constant for the 12-dihydroxyanthraquinone-ethanol complex is obtained

    Criminal Protection from Misleading Advertisements on Social Media Under the Bahraini Consumer Protection Law

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    Providing effective criminal protection for the consumer from the danger of misleading advertisements spread through social media has become an imperative necessity. It contains many legal problems, especially in light of the increasing spread of such advertisements simultaneously with the significant increase of e-commerce. In this paper, we demonstrate the adequacy of criminal protection for the consumer provided by the Bahraini Consumer Protection Law in the face of misleading and deceptive acts through commercial advertisements using social media, and the extent of consumer awareness of it

    Ritualized Submission and the Reduction of Aggression in an Invertebrate

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    SummaryRitualized behaviors that signify acceptance of a dominance relationship and reduce aggression between rivals are a common feature of vertebrate social behavior [1, 2]. Although some invertebrates, including crayfish [3], lobsters [4], and ants [5], display dominance postures, more complex dominance rituals and their effects on fitness have not been reported. We found that crayfish display such a complex ritual, when two males engaged in pseudocopulatory behavior to signify their dominance relationship. This was followed by a reduction in aggression and an increased likelihood of the subordinate's survival. Pseudocopulation was initiated by the eventual dominant and could be accepted or refused by the eventual subordinate. The frequency of aggressive behavior declined significantly during the first hour in all pairs that pseudocopulated but remained high in pairs that did not. Whereas all the subordinate members of pairs that pseudocopulated survived the initial 24 hr of pairing, half of subordinates that did not pseudocopulate were killed during that time. This differential mortality indicates that the reduction of aggression induced by the pseudocopulatory ritual directly enhances the differential survival of male crayfish that engage in this behavior

    Statistical exponential distribution function as distance indicator to stellar groups

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    AbstractIn this paper, statistical distribution functions are developed for distance determination of stellar groups. This method depends on the assumption that, absolute magnitudes and apparent magnitudes follow an exponential distribution function. The developed approaches have been implemented to determine distances of some clusters and stellar associations. The comparison with the distances derived by different authors revealed good agreement

    Copolymerization of Acrylamide with Acrylic acid

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    Low conversion copolymerization of acrylamide AM (monomer-1) have been conducted with acrylic acid AA in dry benzene at 70°C , using Benzoyl peroxide BPO as initiator . The copolymer composition has been determined by elemental analysis. The monomer reactivity ratios have been calculated by the Kelen-Tudos and Finman-Ross graphical procedures. The derived reactivity ratios (r1, r2) are: (0.620, 0.996) for (AM / AA) systems , and found that the reactivity of the monomer AA is more than the monomer AM in the copolymerization of (AA/AM) system. The reactivity ratios values were used for microstructures calculation

    The Role of Workplace Enviousness on Individual Productivity and Organizational Behavior

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    As a result of its negative consequences for college academics, workplace envy is one of the important areas to study and investigate its results. Thus, this study attempts to find out individuals’ productivity affected by envy in the workplace (CWBI) and organizational citizenship behavior directly benefi ts individuals (OCBI) in the context of Iraqi colleges. A survey was conducted among the lecturers at Baghdad University’s colleges in Iraq, with 182 lecturers representing a response rate of 50%. The researcher used two-step approach with partial least squares-structural equation modeling by Smart PLS to test the hypotheses. As anticipated, the research findings point that workplace envy positively influenced CWBI (accepting H1). Furthermore, results indicated that workplace envy negatively influenced OCBI (accepting H2). The results of this research have various implications for colleges in general and Iraqi colleges in particular. The scientific impact that the results of the present study will contribute to practitioners is demonstrated by highlighting the factors that lead to reducing CWBI and strengthening OCBI in colleges. To enhance the OCBI and minimize the CWBI in colleges, it is advised that the management should encourage academic cooperation and create a work environment suitable for the academics. This can be achieved by forming research teams to work on joint scientific projects and by allowing qualified academics to participate in teaching, supervising postgraduate students, and discussion committees. Providing positive organizational support can motivate the academics to perform better, exhibit responsible behavior, and become productive members of the college community

    Effect of Khat (Catha edulis) Use on the Bioavailability, Plasma Levels and Antimalarial Activity of Chloroquine.

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    OBJECTIVES This study aimed to evaluate the effect of khat (Catha edulis) on chloroquine (CQ) bioavailability in healthy Yemeni adults and its effect on CQ plasma levels and parasite clearance among malaria patients. METHODS This study took place between January and April 2007 in Bajil and Sana'a, Yemen. Two CQ doses (600 mg each) were given to 15 healthy males on separate occasions; the first dose was followed by a khat-chewing session (phase one) while controls abstained from khat-chewing for the second (phase two). Additionally, 103 patients with Plasmodium falciparum-induced malaria, including both regular khat chewers (n = 57) and non-khat chewers (n = 46), were treated with CQ (25 mg/kg) over three days. Pharmacokinetic parameters were analysed among both controls and malaria patients. Parasite clearance was also investigated for the latter group. RESULTS The mean area under the concentration-time curve (AUC) was 2,108.9 versus 2,797.4 ng/hour/mL, mean peak plasma concentration (Cmax) was 415.6 versus 508.7 ng/mL and mean time to reach Cmax was 3.8 versus 3.6 hours for controls in phase one versus phase two, respectively; both AUC and Cmax levels were significantly reduced by khat-chewing (P <0.050). For khat- versus non-khat-chewing malaria patients, mean plasma CQ concentrations were 266.4 ng/mL versus 427.5 ng/mL (P <0.001). Furthermore, CQ was effective in 71.7% and 75.4% of non-khat and khat-chewing malaria patients, respectively (P = 0.823). CONCLUSION Khat-chewing was found to significantly reduce plasma CQ levels among healthy volunteers and malaria patients. While receiving CQ treatment, patients should be advised not to chew khat
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