498 research outputs found
A Primal-Dual Based Power Control Approach for Capacitated Edge Servers
The intensity of radio waves decays rapidly with increasing propagation
distance, and an edge server's antenna needs more power to form a larger signal
coverage area. Therefore, the power of the edge server should be controlled to
reduce energy consumption. In addition, edge servers with capacitated resources
provide services for only a limited number of users to ensure the quality of
service (QoS). We set the signal transmission power for the antenna of each
edge server and formed a signal disk, ensuring that all users were covered by
the edge server signal and minimizing the total power of the system. This
scenario is a typical geometric set covering problem, and even simple cases
without capacity limits are NP-hard problems. In this paper, we propose a
primal-dual-based algorithm and obtain an -approximation result. We compare
our algorithm with two other algorithms through simulation experiments. The
results show that our algorithm obtains a result close to the optimal value in
polynomial time
Research on Impulse Radio Ultra - wideband Positioning Method Based on Combined BP Neural Network and SVM
Intelligent tour guide is a comprehensive service based on tourist\u27s location, which is closely related to Geographic Information System (GIS), mobile positioning technology and Location-Based Service (LBS). But the intelligent tour guide field urgently needs the integrated positioning and navigation technology inside and outside the room. IR-UWB technology is suitable for positioning, tracking, navigation and communication in complex indoor environment, and is considered as the most potential indoor positioning technology to realize seamless connection between indoor and outdoor with outdoor positioning technologies such as GPS. However, one of the main problems facing IR-UWB positioning is Non-Line-Of-Sight (NLOS) error. Based on the advantages of BP neural network and support vector machine, this paper proposes a multi-model fusion algorithm to mitigate the NLOS propagation error of the time difference of arrival (TDOA) and the angle of arrival (AOA) of IR-UWB signal, and then uses TDOA/AOA hybrid positioning that mitigates the NLOS error. Simulation results show that the combined algorithm has stronger NLOS resistance and higher positioning accuracy than the single machine learning algorithm in mitigation NLOS errors
Mobile Internet based M-Commerce Management Architecture & System
The mobile Internet exits already in very many forms on the market. However, there are definitely still a lot of possibilities to improve the current concepts and solution, and thus a lot of room for future R&D activities. This paper is divided five parts as followings: First of all, introduction; Secondly, the basic concept of mobile Internet is introduced, and itsā develop- ment status is described simply; Thirdly, the process of come into being M-commerce based on Internet and the existing modes of M-commerce are discussed respectively; the differences between E-commerce and Mcommerce are also shown in the paper; Fourthly, an M-commerce system model is presented, the model involves itsā basic elements such as hierarchical architecture, management mechanism, system decision-making, application procedure etc; Fifthly, development trend and application fields for coming the new economics times are forecasted; Finally, how to build a M-commerce management system and make applications for business via CERNET** (one of the biggest Internet platform in China) are introduced primarily in end of the paper
A Local-Ratio-Based Power Control Approach for Capacitated Access Points in Mobile Edge Computing
Terminal devices (TDs) connect to networks through access points (APs)
integrated into the edge server. This provides a prerequisite for TDs to upload
tasks to cloud data centers or offload them to edge servers for execution. In
this process, signal coverage, data transmission, and task execution consume
energy, and the energy consumption of signal coverage increases sharply as the
radius increases. Lower power leads to less energy consumption in a given time
segment. Thus, power control for APs is essential for reducing energy
consumption. Our objective is to determine the power assignment for each AP
with same capacity constraints such that all TDs are covered, and the total
power is minimized. We define this problem as a \emph{minimum power capacitated
cover } (MPCC) problem and present a \emph{minimum local ratio} (MLR) power
control approach for this problem to obtain accurate results in polynomial
time. Power assignments are chosen in a sequence of rounds. In each round, we
choose the power assignment that minimizes the ratio of its power to the number
of currently uncovered TDs it contains. In the event of a tie, we pick an
arbitrary power assignment that achieves the minimum ratio. We continue
choosing power assignments until all TDs are covered. Finally, various
experiments verify that this method can outperform another greedy-based way
Development and characterization of microsatellite loci for Fenneropenaeus penicillatus Alcock
Eight novel microsatellite loci from the genome of Fenneropenaeus penicillatus Alcock were developed using the protocol of fast isolation by amplified fragment length polymorphism of sequences containing repeats (FIASCO). Thirty (30) wild individuals were used to analyze the polymorphism of these eight microsatellite markers. The results show that the number of alleles per locus and the polymorphism information content ranged from 2 to 7 and from 0.2076 to 0.7484, respectively. The observed and expected heterozygosity were 0.1724 to 0.9130 and 0.1639 to 0.7314, respectively. These microsatellite primers will be used for further population genetic studies, constructing genetic linkage maps or locating quantitative trait locus (QTL) of F. penicillatus Alcock.Keywords: Genetic markers, Fenneropenaeus penicillatus Alcock, microsatellite
A Robust Integrated Multi-Strategy Bus Control System via Deep Reinforcement Learning
An efficient urban bus control system has the potential to significantly
reduce travel delays and streamline the allocation of transportation resources,
thereby offering enhanced and user-friendly transit services to passengers.
However, bus operation efficiency can be impacted by bus bunching. This problem
is notably exacerbated when the bus system operates along a signalized corridor
with unpredictable travel demand. To mitigate this challenge, we introduce a
multi-strategy fusion approach for the longitudinal control of connected and
automated buses. The approach is driven by a physics-informed deep
reinforcement learning (DRL) algorithm and takes into account a variety of
traffic conditions along urban signalized corridors. Taking advantage of
connected and autonomous vehicle (CAV) technology, the proposed approach can
leverage real-time information regarding bus operating conditions and road
traffic environment. By integrating the aforementioned information into the
DRL-based bus control framework, our designed physics-informed DRL state fusion
approach and reward function efficiently embed prior physics and leverage the
merits of equilibrium and consensus concepts from control theory. This
integration enables the framework to learn and adapt multiple control
strategies to effectively manage complex traffic conditions and fluctuating
passenger demands. Three control variables, i.e., dwell time at stops, speed
between stations, and signal priority, are formulated to minimize travel
duration and ensure bus stability with the aim of avoiding bus bunching. We
present simulation results to validate the effectiveness of the proposed
approach, underlining its superior performance when subjected to sensitivity
analysis, specifically considering factors such as traffic volume, desired
speed, and traffic signal conditions
Effects of land use, topography, climate and socio-economic factors on geographical variation pattern of inland surface water quality in China
The deterioration of water quality has become a primary environmental concern worldwide. Understanding the status of water quality and identifying the influencing factors are important for water resources management. However, reported analyses have mostly been conducted in small and focused areas. It is still unclear if factors driving spatial variation in water quality would be different in extended spatial scales. In this paper, we analyzed spatial pattern of inland surface water quality in China using a dataset with four water quality parameters (i.e., pH, DO, NH4+-N and CODMn) and the water quality level. We tested the effects of anthropogenic (i.e., land use and socio-economic) and natural (i.e., climatic and topographic) factors on spatial variation in water quality. The study concluded that the overall inland surface water quality in China was at level III (fair). Water quality level was strongly correlated with CODMn and NH4+-N concentration. In contrast to reported studies that suggested land use patterns were the determinants of inland surface water quality, this study revealed that both anthropogenic and natural factors played important roles in explaining spatial variation of inland surface water quality in China. Among the tested explanatory variables, mean elevation within watershed appeared as the best predictor for pH, while annual precipitation and mean air temperature were the most important explanatory variables for CODMn and DO, respectively. NH4+-N concentration and water quality level were most strongly correlated with the percent of forest cover in watershed. Compared to studies at smaller spatial scales, this study found different influencing factors of surface water quality, suggesting that factors may play different roles at different spatial scales of consideration. Therefore management policies and measures in water quality control must be established and implemented accordingly. Since currently adopted parameters for monitoring of inland surface water quality in China are largely influenced by natural variables, additional physicochemical and biological indicators are needed for a robust assessment of human impacts on water quality
Regulation of Free Fatty Acid Receptor 4 on Inflammatory Gene Induced by LPS in Large Yellow Croaker (Larimichthys crocea)
Free fatty acid receptor 4 (FFAR4) plays a key role in regulating the inflammatory response in mammals. The present study aimed to investigate the function of large yellow croaker FFAR4 on inflammation. In the present study, ffar4 was widely expressed in 10 tissues of large yellow croaker including gill, head kidney and spleen. Further studies showed that treatment of head kidney macrophages with agonists (TUG891 or GSK137647A) or overexpression of ffar4 reduced the mRNA expression of pro-inflammatory genes induced by LPS, and increased the expression of pparĪ³. Treatment of macrophages with antagonist AH7614 increased the mRNA expression of pro-inflammatory genes induced by LPS, and decreased the mRNA expression of pparĪ³. In order to verify the immunomodulatory effect of PPARĪ³, PPARĪ³ was overexpressed in macrophages which significantly reduced the mRNA expression of pro-inflammatory genes il6, il1Ī², il8, tnfĪ± and cox2. Moreover, results of dual-luciferase assays showed that PPARĪ³ downregulated the transcriptional activity of il6 and il1Ī² promoters. In conclusion, FFAR4 showed anti-inflammatory effects on LPS-induced inflammation in large yellow croaker
Assessing the impact of curcumin on dualāspecies biofilms formed by Streptococcus mutans and Candida albicans
Streptococcus mutans and Candida albicans are often isolated from plaques associated with early childhood caries. However, there are limited studies examining how these microorganisms interact with one another and how best to manage them. Recent studies have shown that curcumin (CUR), a natural compound, has the potential to independently control both of these microorganisms. The purpose of this study was to investigate how S. mutans and C. albicans respond in monoā and dualāspecies biofilms challenged with CUR. Quantitative biofilm biomass and viability were first evaluated and supported by liveādead PCR to assess biofilm composition. Confocal laser scanning microscopy (CLSM) was used to evaluate the exopolysaccharide (EPS) content and thickness of the biofilms, and the structure of the biofilms and morphology of the cells were observed by scanning electron microscopy (SEM). Quantitative realātime PCR (qRTāPCR) was applied to assess relative gene expression. The 50% minimum biofilm eradication concentration (MBEC50) of CUR against S. mutans and C. albicans was 0.5 mM. The biomass and viability decreased after treatment with CUR both in dualāspecies biofilms and in monoāspecies biofilm. CUR inhibited S. mutans and C. albicans in both monoā and dualāspecies biofilms. Streptococcus mutans was more sensitive to CUR in dualāspecies biofilm than in monoāspecies biofilms, whereas C. albicans was less sensitive in dualāspecies biofilms. EPS production was decreased by CUR in both monoā and dualāspecies biofilms, which coincided with the downregulation of glucosyltransferase and quorum sensingārelated gene expression of S. mutans. In C. albicans, the agglutininālike sequence family of C. albicans was also downregulated in dualāspecies biofilms. Collectively, these data show the potential benefit of using a natural antimicrobial, CUR, to control cariesārelated dualāspecies plaque biofilms
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