We investigate the problem of achieving global optimization for distributed channel selections in cognitive radio networks (CRNs), using game theoretic solutions. To cope with the lack of centralized ...control and local influences, we propose two special cases of local interaction game to study this problem. The first is local altruistic game, in which each user considers the payoffs of itself as well as its neighbors rather than considering itself only. The second is local congestion game, in which each user minimizes the number of competing neighbors. It is shown that with the proposed games, global optimization is achieved with local information. Specifically, the local altruistic game maximizes the network throughput and the local congestion game minimizes the network collision level. Also, the concurrent spatial adaptive play (C-SAP), which is an extension of the existing spatial adaptive play (SAP), is proposed to achieve the global optimum both autonomously as well as rapidly.
Abstract
The existing multi-person collaborative design scheme of Building Information Modeling (BIM) integrated with blockchain faces problems such as poor reliability of BIM drawing, inconsistent ...drawing information, redundant information, and inaccurate protection of copyright interests. This paper proposes a multi-person collaborative design model for BIM drawing that combines blockchain and InterPlanetary File System (IPFS). This model uses blockchain to store drawing design information to protect the copyright interests of designers and combines IPFS to ensure the reliability of drawing. A cycle division mechanism is designed to solve the problem of drawing information synchronization when multiple people collaborate in design. The Semantic Differential Transaction (SDT) method is used to achieve incremental update of drawing and reduce the information redundancy of the blockchain. Finally, a comparative analysis and validation evaluation of the scheme is carried out, and the usability of the scheme is illustrated with an illustrative example. The results show that: (1) proposed scheme is feasible for multi-person collaborative design; (2) proposed scheme can effectively ensure the reliability of drawing and reduce the redundancy of blockchain information, so as to achieve copyright protection for designers.
In this paper, we propose a novel indoor passive localization approach called eigenspace-based DOA with direct-path recognition (ES-DPR), based on a DOA estimation algorithm with multiple ...omnidirectional antennas deployed in a uniform linear array (ULA). To address the multipath propagation interference problem in the indoor environments, we utilize the azimuth and RSS estimation results, which are calculated by using the eigenspace-based DOA (ES-DOA) algorithm, in a novel style. A direct-path bearing recognition algorithm is introduced to identify the real DOA of the signal source in different indoor environments, by combining the azimuth and RSS estimation with ensemble learning methods. Numerical simulations are conducted to verify the validity and superiority of the proposed method. The results show that the proposed ES-DPR method can achieve high resolution and has strong anti-noise capability in dealing with the multipath signals, and the direct-path recognition algorithm is reliable and robust in different indoor environments, even in undetectable direct-path conditions.
•A NiCoCrAlY coating that has been oxidized at high temperature is removed by electrochemical stripping.•The recoated coating exhibits lower oxidation rate, but is more likely to spall off during ...cyclic oxidation.•Elements interdiffusion with the alloy substrate causes the difference in oxidation behavior.•The consumption of Al in the recoated coating was larger than that in the ordinary one after diffusion into the alloy.
NiCoCrAlY coating that has been oxidized at high temperature is successfully removed by electrochemical stripping from a nickel-based superalloy, which is followed by recoating a fresh one. Then oxidation behavior of the recoated NiCoCrAlY coating is investigated in comparison with the ordinary one. Results indicate that the recoated coating exhibits a lower oxidation rate with a rate constant of 3.1×10−14 g2 cm-4s-1 at 1000 °C. However, its oxide scale is more likely to spall off than that of the ordinary one in cyclic oxidation. Elements interdiffusion between the NiCoCrAlY coatings and the alloy substrate leads to the different oxidation behavior.
Environmental properties are important factors in structuring soil microbial communities. The primary driving factors vary in different ecosystems. In the present work, we analyzed the microbial ...communities of rhizosphere and bulk soils associated with the halophyte Alhagi sparsifolia across three salt/water gradients in the desert area around Ebinur Lake Basin, China, using high-throughput sequencing technology. We found that there were significant differences in soil water content (SWC), soil salinity (SAL), total nitrogen (TN), and total phosphorus (TP) contents between the three water/salt gradients. In the L (low water and salt) plot, Actinobacteria was the most abundant bacterial phylum while Ascomycota was the dominant fungal phylum. The relative abundance of Actinobacteria was negatively correlated with soil pH, soil organic carbon (SOC), TP, and available phosphorus (AP). The abundance of Bacteroidetes was significantly positively correlated with soil SOC, SWC, SAL, pH, TN, and TP (P < 0.05). The abundance of fungal phylum Chytridiomycota was significantly positively correlated with pH (P < 0.01), SWC, AP, and sulfate ion (P < 0.05). SOC and nitrate nitrogen were the main factors impacting the bacterial community, while ammonium nitrogen (NH.sub.4 .sup.+) and TP were the main driving forces for the fungal community. Soil nutrients were the main contributors to the dissimilarities in the bacterial and fungal communities, explaining 48.06% and 44.45% of the variation. SWC, SAL, and pH explained only a small percentage of the microbial community dissimilarity. In conclusion, soil microbial community structure was affected by SWC, SAL, pH, and soil nutrients, with soil nutrients as the main driving factors. Nitrogen has a differential effect on the different microbial communities: bacterial communities of Alhagi sparsifolia were mainly affected by nitrate nitrogen, while fungal communities were mainly driven by ammonium nitrogen.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
UAV cooperative control has been applied in many complex UAV communication networks. It remains challenging to develop UAV cooperative coverage and UAV energy-efficient communication technology. In ...this paper, we investigate current works about UAV coverage problem and propose a multi-UAV coverage model based on energy-efficient communication. The proposed model is decomposed into two steps: coverage maximization and power control, both are proved to be exact potential games (EPG) and have Nash equilibrium (NE) points. Then the multi-UAV energy-efficient coverage deployment algorithm based on spatial adaptive play (MUECD-SAP) is adopted to perform coverage maximization and power control, which guarantees optimal energy-efficient coverage deployment. Finally, simulation results show the effectiveness of our proposed approach, and confirm the reliability of proposed model.
Multifunctional nanotheranostic agents have been highly commended due to the application to image-guided cancer therapy. Herein, based on the chemically disordered face centered cubic (fcc) FePt ...nanoparticles (NPs) and graphene oxide (GO), we develop a pH-responsive FePt-based multifunctional theranostic agent for potential in vivo and in vitro dual modal MRI/CT imaging and in situ cancer inhibition. The fcc-FePt will release highly active Fe ions due to the low pH in tumor cells, which would catalyze H2O2 decomposition into reactive oxygen species (ROS) within the cells and further induce cancer cell apoptosis. Conjugated with folic acid (FA), the iron platinum-dimercaptosuccinnic acid/PEGylated graphene oxide-folic acid (FePt-DMSA/GO-PEG-FA) composite nanoassemblies (FePt/GO CNs) could effectively target and show significant toxicity to FA receptor-positive tumor cells, but no obvious toxicity to FA receptor-negative normal cells, which was evaluated by WST-1 assay. The FePt-based multifunctional nanoparticles allow real-time monitoring of Fe release by T2-weighted MRI, and the selective contrast enhancement in CT could be estimated in vivo after injection. The results showed that FePt-based NPs displayed excellent biocompatibility and favorable MRI/CT imaging ability in vivo and in vitro. Meanwhile, the decomposition of FePt will dramatically decrease the T2-weighted MRI signal and increase the ROS signal, which enables real-time and in situ visualized monitoring of Fe release in tumor cells. In addition, the self-sacrificial decomposition of fcc-FePt will be propitious to the self-clearance of the as-prepared FePt-based nanocomposite in vivo. Therefore, the FePt/GO CNs could serve as a potential multifunctional theranostic nanoplatform of MRI/CT imaging guided cancer diagnosis and therapy in the clinic.
Bioaerosol significantly affect air quality and public health. However, limited information on bioaerosol at various levels of air quality over a long-term period has prevented our proper ...understanding of the possible threat to human health. In this study, airborne microbial samples were collected in Xi’an, China, from Apr. 2016 to Feb. 2017. The content of total airborne microbes (TAMs) was determined by fluorescent staining with DAPI (4′, 6-diamidino-2-phenylindole). A comparative investigation was emphatically conducted concerning the concentration of TAMs at various air quality levels. The results indicated that the concentration of TAMs showed significant seasonal variation. The concentration variation in different seasons followed the order of winter (6.77 × 105 cells/m3) > autumn (4.22 × 105 cells/m3) > spring (2.38 × 105 cells/m3) > summer (1.66 × 105 cells/m3). The mean concentration of TAMs on hazy days (6.12 × 105 ± 3.50 × 105 cells/m3) was significantly higher than that on non-hazy days (2.15 × 105 ± 1.26 × 105 cells/m3). Importantly, the concentration of TAMs increased firstly and then slightly decreased with the deterioration of air quality, and the maximum concentration was observed at moderate pollution level. The joint effect of meteorological and environmental factors was found to be an important influence mechanism on bioaerosol concentrations. Furthermore, snowfall was found capable of improving air quality by reducing concentration of TAMs. The present results will improve our understanding of effect of air pollution on airborne microbes.
•The monitoring of total airborne microbes (TAMs) at various air quality levels over a long-term period were conducted.•The concentration of TAMs showed significant seasonal variation.•The concentration of TAMs on hazy days was much higher than that on non-hazy days.•The concentration of TAMs did not always increase with the deterioration of air quality.•The joint effect of meteorological and environmental factors may be important on bioaerosols.
Submarine groundwater discharge (SGD) has been recognized as an important pathway for nutrients into estuaries, coasts, and the adjacent seas. In this study, 222Rn was used to estimate the ...SGD‐associated nutrient fluxes into an aquaculture area in a typical tropical bay (Maowei Sea, China). The SGD into the Maowei Sea during June 2016 was estimated to be 0.36 ± 0.33 m d−1 and was associated with SGD‐derived dissolved inorganic nitrogen (DIN), dissolved inorganic phosphorus (DIP), and dissolved silicon (DSi) fluxes (mol d−1) of (4.5 ± 5.5) × 106, (5.3 ± 9.1) × 104, and (9.4 ± 9.3) × 106, respectively. The SGD‐derived nutrients (i.e., DIN, DIP, and DSi) were more than 1.9, 0.9, and 3.6 times the amounts in the local river input and served as dominant sources in the nutrient budgets in the Maowei Sea. Moreover, the N/P ratios in the SGD around the Maowei Sea were high (mean: 64), and these ratios likely exceeded the environmental self‐purification capacity, thereby enhancing the biomass and changing the phytoplankton community structure. Therefore, SGD processes with derived nutrients may affect the biogeochemical cycles and marine ecological environment in the Maowei Sea. Furthermore, the N/P ratios (∼67) in oysters are very close to those in the SGD in the Maowei Sea; this coincidence suggests that the high N/P ratios in the SGD are likely to be one of the most important sources that support oyster aquaculture, which might weaken the burden of water eutrophication in the Maowei Sea.
Key Points
SGD is the dominant source of nutrients to the Maowei Sea
The SGD‐derived nutrients are higher in the Maowei Sea than those estimated in other similar studies
SGD‐derived nutrients could support high‐quantity aquaculture (oyster) in the Maowei Sea
In this study, we prepared homemade fruit shell-activated carbon (SAC) with efficient adsorption of new pollutants and used it in the removal of methylene blue dye (MB) and ofloxacin antibiotic (OFL) ...in water. We fitted the experimental data for MB and OFL adsorption with isothermal and kinetic models and performed extensive characterization to study the properties of SAC. We also studied the effects of solution pH, dosage amount, initial concentration, and coexisting ions on the adsorption capacity. The results show that SAC has a rich pore structure, and electrostatic interactions are its main adsorption mechanism. Adjusting the solution pH by changing the SAC dosage and removing the K+, SO42−, and Cu2+ could increase the removal of MB and OFL to 99.9% and 97.6%, respectively. In addition, the adsorption capacity of SAC for MB remained at more than 50% of the initial state after three iterations of adsorption regeneration, showing a good regeneration ability. These results show the potential of SAC in replacing conventional activated carbon to remove new pollutants.
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