Integrating mobile edge computing (MEC) with small cell networks has been conceived as a promising solution to provide pervasive computing services. However, the interactions among small cells due to ...inter-cell interference, the diverse application-specific requirements, as well as the highly dynamic wireless environment make it challenging to design an optimal computation offloading scheme. In this paper, we focus on the joint design of computation offloading and interference coordination for edge intelligence empowered small cell networks. To this end, we propose a distributed multi-agent deep reinforcement learning (DRL) scheme with the objective of minimizing the overall energy consumption while ensuring the latency requirements. Specifically, we exploit the collaboration among small cell base station (SBS) agents to adaptively adjust their strategies, considering computation offloading, channel allocation, power control, and computation resource allocation. Further, to decrease the computation complexity and signaling overhead of the training process, we design a federated DRL scheme which only requires SBS agents to share their model parameters instead of local training data. Numerical results demonstrate that our proposed schemes can significantly reduce the energy consumption and effectively guarantee the latency requirements compared with the benchmark schemes.
Conspectus Quantum interference effects (QIEs), which offer unique opportunities for the fine-tuning of charge transport through molecular building blocks by constructive or destructive quantum ...interference, have become an emerging area in single-molecule electronics. Benefiting from the QIEs, charge transport through molecular systems can be controlled through minor structural and environmental variations, which cause various charge transport states to be significantly changed from conductive to insulative states and offer promising applications in future functional single-molecule devices. Although QIEs were predicted by theoreticians more than two decades ago, only since 2011 have the challenges in ultralow conductance detection originating from destructive quantum interference been overcome experimentally. Currently, a series of single-molecule conductance investigations have been carried out experimentally to detect constructive and destructive QIEs in charge transport through various types of molecular junctions by altering molecular patterns and connectivities. Furthermore, the use of QIEs to tune the properties of charge transport through single-molecule junctions using external gating shows vital potential in future molecular electronic devices. The experimental and theoretical investigations of QIEs offer new fundamental understanding of the structural–electronic relationships in molecular devices and materials at the nanoscale. In this Account, we discuss our progress toward the experimental detection, manipulation, and further application of QIEs in charge transport through single-molecule junctions. These experiments were carried out continuously in our previous group at the University of Bern and in our lab at Xiamen University. As a result of the development of mechanically controllable break junction (MCBJ) and scanning tunneling microscope break junction (STM-BJ) techniques, we could detect ultralow charge transport through the cross-conjugated anthraquinone center, which was one of the earliest experimental studies of QIEs. In close cooperation with organic chemists and theoretical physicists, we systematically investigated charge transport through single-molecule junctions originating from QIEs in conjugated centers ranging from simple single benzene to polycyclic aromatic hydrocarbons (PAHs), heteroaromatics, and even complicated metalla-aromatics at room temperature. Then we further investigated the quantitative correlation between molecular structure and quantum interference by altering different molecular patterns and connectivities in homologous series of PAHs and heteroatom systems. Additionally, external chemical and electrochemical gating of single-molecule devices can be used for direct QIE manipulation via not only tuning molecular conjugation but also shifting the electrode Fermi level. Our study further suggested that distinguishable differences in conductance resulting from QIEs offer opportunities to detect photothermal reaction kinetics and to recognize isomers at the single-molecule scale. These investigations demonstrate the universality of QIEs in charge transport through various molecular building blocks. Moreover, effective manipulation of QIEs leads to various novel phenomena and promising applications in molecular electronic devices.
With the rapid development of artificial intelligence technology, its application in education has become increasingly widespread, especially in English teaching in colleges and universities. Using ...artificial intelligence technology to build an intelligent teaching mode can effectively improve the quality of teaching and students’ learning efficiency. The study adopts Bayesian algorithm and Bayesian-based learning tracking model (BKT and BF-BKT) as the main methods to optimize the teaching mode by analyzing learners’ mastery of knowledge points and behavioral performance. The results show that the maximum response time of the model is only 1038.59 milliseconds when the number of users is 120, proving the model’s efficiency in handling large-scale data. In addition, the intelligent teaching model positively impacted both teacher-student interaction and student learning ability. The teacher speech ratio decreased from 80.26% to 62.53%, and the students’ autonomy and participation increased significantly; the mean value of students’ learning ability in independent learning and critical thinking exceeded 4.00. The application of AI technology in teaching English in colleges and universities can significantly improve the quality of teaching and students’ learning effect.
This study aims to clarify the effects of different concentrations of sodium chloride on the carbon and nitrogen metabolism and yield of Tartary buckwheat. The salt-sensitive cultivar Yunqiao 2 was ...pot-grown and treated with four salt concentrations including 0, 2, 4, and 6 g kg
. The root morphology index increased from seedling stage to maturate stage. The content of soluble protein in the leaves reached the maximum at the anthesis stage, and the other substances content and the enzymes activity related to carbon and nitrogen metabolism reached the maximum at the grain filling stage. The root morphology index, root activity; invertase, amylase, sucrose synthase, and sucrose phosphate synthase activities; nitrate-nitrogen, ammonium nitrogen, and soluble protein content; and nitrate reductase and glutamate synthase activities increased first and reached the maximum at 2 g kg
treatment and then decreased with increasing salt stress concentration. The content of soluble sugars and sucrose and the activity of glutamate dehydrogenase increased continuously with increasing salt concentration, and reached the maximum in the 6 g kg
treatment. The grain number per plant, 100-grain weight, and yield per plant increased first and reached the maximum at 2 g kg
treatment and then decreased with increasing salt stress concentration. In summary, moderate salt stress (2 g kg
) can promote the root growth, increase the content of carbon and nitrogen metabolism-related substances and enzyme activity, and increase the yield per plant of Tartary buckwheat.
The cloud radio access network (C-RAN) is a promising architecture for future radio access networks (RANs) due to its advantages in cost efficiency, flexibility, and utilization efficiency. To fully ...reap these benefits, this paper focuses on joint optimization of user grouping, virtual base station (VBS) clustering, and transmit beamforming in C-RAN downlink networks for maximizing the system utility, subject to the diverse quality-of-service (QoS) requirements of users and the power constraints of distributed remote radio heads (RRHs). To tackle the high computational complexity in solving the nonconvex combinatorial optimization problem, a two-stage solution is proposed. Specifically, a dynamic user-centric scheduling algorithm is developed to form user groups and cluster RRHs into VBSs by exploiting the nonuniform distribution of users. Then, an iterative transmit beamformer optimization algorithm is devised to coordinate the transmit beamforming among the VBSs to mitigate the intracell and intercell interference, hence further enhancing the overall system utility. Evaluation results demonstrate that the proposed algorithm achieves significant performance gain over various reference algorithms in terms of system utility, system throughput, and energy efficiency.
As a newly class of endogenous phytohormones, strigolactones (SLs) regulate crop growth and yield formation by interacting with other hormones. However, the physiological mechanism of SLs affect the ...yield by regulating the balance of endogenous hormones of Tartary buckwheat is still unclear.
In this study, a 2-year field experiment was conducted on Tartary buckwheat (Jinqiao 2) to study the effects of different concentrations (0, 10, and 20 µmol/L) of artificial synthetic analogs of SLs (rac-GR24) and inhibitor of SL synthesis (Tis-108) on the growth, endogenous-hormone content, and yield of Tartary buckwheat. The main-stem branch number, grain number per plant, grain weight per plant, and yield of Tartary buckwheat continuously decreased with increased rac-GR24 concentration, whereas the main-stem diameter and plant height initially increased and then decreased. Rac-GR24 treatment significantly increased the content of SLs and abscisic acid (ABA) in grains, and it decreased the content of Zeatin (Z) + Zeatin nucleoside (ZR). Conversely, Tis-108 treatment decreased the content of SLs and ABA but increased the content of Z + ZR. Results of correlation analysis showed that the content of ABA and SLs, the ratio of SLs/(Z + ZR), SLs/ABA, and ABA/(Z + ZR) were significantly negatively correlated with the yield of Tartary buckwheat, and that Z + ZR content was significantly positively correlated with the yield. Regression analysis further showed that ABA/ (Z + ZR) can explain 58.4% of the variation in yield.
In summary, by adjusting the level of endogenous SLs in Tartary buckwheat, the balance of endogenous hormones in grains can be changed, thereby exerting the effect on yield. The results can provide a new agronomic method for the high-yield cultivation of Tartary buckwheat.
This study focused on the differential metabolomic effects between water extracts of Polygoni Multiflori Radix and Polygoni Multiflori Radix Preparata in rats. The extracts were subsequently ...administered for 28 d. Serum biochemical indicators were tested, hematoxylin–eosin staining and immunohistochemistry staining were used to detect histopathological changes in the livers. Ultra-performance LC/quadrupole time-of-flight mass spectrometry was used to detect the changes in endogenous metabolites. Finally, we performed detailed analysis of the changes in metabolic pathways. Hematoxylin–eosin staining and immunohistochemistry staining results indicated that the water extracts of Polygoni Multiflori Radix and Polygoni Multiflori Radix Preparata had mild liver injury effect. Fifty-two differential endogenous biomarkers were confirmed as potential biomarkers between Polygoni Multiflori Radix and Polygoni Multiflori Radix Preparata groups. In the positive ion mode, the biomarkers included 31 Phosphatidyl cholines (PCs), six lysoPCs, and ceramide. In the negative ion mode, 12 biomarkers were confirmed, including glycodeoxycholic acid, chenodeoxycholic acid, and deoxycholic acid, etc. In Hydrophilic Interaction Liquid Chromatography (HILIC) mode, nine biomarkers were confirmed, including niacinamide, L-palmitoylcarnitine, and butyrylcarnitine, etc. Using MetaboAnalyst 4.0, six related metabolic pathways, including taurine and hypotaurine metabolism, sphingolipid metabolism, glycerophospholipid metabolism, nicotinate and nicotinamide metabolism, arginine and proline metabolism, and tryptophan metabolism and primary bile synthesis, were confirmed as the most differential pathways between the Polygoni Multiflori Radix and Polygoni Multiflori Radix Preparata groups.
This article proposes a novel type of the 2nd and 4th harmonic torque suppression methods during conventional single-phase open-circuit fault-tolerant operation when considering the 3rd harmonic ...back-EMF of permanent magnet synchronous motor (PMSM). These suppression methods are based on injecting the 3rd harmonic currents into the two remaining healthy phases, which produces harmonic torque of opposite phase to cancel the original one. The suppression can have three different constraints: maintaining the average torque, eliminating the 2nd harmonic torque, and eliminating the 4th harmonic torque. They cannot be achieved simultaneously. Combining any two of them leads to a particular injection method. Three particular methods are developed and their performance are investigated by theoretical analysis and compared against the conventional one. The proposed fault tolerant control strategies are applicable to various fault-tolerant inverter topologies by using these novel phase current references, whereas the current tracking algorithms could be different. To ease validation, a four-leg inverter topology is selected to implement such injection methods to a three-phase star-connected 10-pole/9-slot PMSM. The experiments validate that tracking the proposed current references can effectively suppress the harmonic torque, which confirms the theoretical analysis.
The application rate of potassium fertilizer is closely related to the yield of crops. Thin-shelled Tartary buckwheat is a new variety of Tartary buckwheat with the advantages of thin shell and easy ...shelling. However, little is known about application rate of potassium fertilizer on the yield formation of thin-shelled Tartary buckwheat. This study aimed to clarify the effect of potassium fertilizer on the growth and yield of thin-shelled Tartary buckwheat. A field experiment to investigate the characteristics was conducted across two years using thin-shelled Tartary buckwheat (Miku 18) with four potassium fertilizer applications including 0 (no potassium fertilizer, CK), 15 (low-concentration potassium fertilizer, LK), 30 (medium-concentration potassium fertilizer, MK), and 45 kg·ha
(high-concentration potassium fertilizer, HK). The maximum and average grain filling rates; starch synthase activity; superoxide dismutase and peroxidase activities in leaves; root morphological indices and activities; available nitrogen, phosphorus, and organic matter content in rhizosphere soil; urease and alkaline phosphatase activities in rhizosphere soil; plant height, main stem node number, main stem branch number, leaf number; grain number per plant, grain weight per plant, and 100-grain weight increased first and then decreased with the increase in potassium fertilizer application rate and reached the maximum at MK treatment. The content of malondialdehyde was significantly lower in MK treatment than in other three treatments. The yields of thin-shelled Tartary buckwheat treated with LK, MK, and HK were 1.22, 1.37, and 1.07 times that of CK, respectively. In summary, an appropriate potassium fertilizer treatment (30kg·ha
) can delay the senescence, promote the grain filling, and increase the grain weight and final yield of thin-shelled Tartary buckwheat. This treatment is recommended to be used in production to achieve high-yield cultivation of thin-shelled Tartary buckwheat.
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