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1.
Artigo em Inglês | MEDLINE | ID: mdl-34988822

RESUMO

Climate has received an increasing attention due to its adverse effects on human health, but the effects on the urinary system are still short of enough evidence. Therefore, we carry out this study to analyze the relationship between meteorological factors and urinary system health in arid areas of western China. In this study, the daily numbers of outpatients with the urinary system diseases from multiple hospitals in three cities in Gansu province (Lanzhou, Zhangye, and Tianshui city) were collected and used for analysis. The distributed lag non-linear models (DLNM) with a quasi-Poisson distribution were used to estimate the associations between meteorological factors and daily outpatients for urinary system diseases in these three cities, and then a multivariate meta-analysis was applied to pool the estimates of city-specific effects. We found that the ambient temperature (AT) and relative humidity (RH) were significantly associated with the outpatient visits of urinary system diseases. The effects of meteorological factors on outpatients with urinary system diseases for both males and females were statistically significant at different lag days. The higher AT and lower RH were associated with the higher risk of urinary system diseases. We also observed substantial lag effects of meteorological factors on outpatients for both males and females. Among all disease types, renal tubule-interstitial diseases had the strongest relationships with meteorological factors. Our results indicate that the higher AT and lower RH may increase the outpatient visits for urinary system diseases, with significant lag effects in semi-arid areas.

2.
IEEE Trans Image Process ; 31: 99-109, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-34793302

RESUMO

Remote sensing scene classification (RSSC) is a hotspot and play very important role in the field of remote sensing image interpretation in recent years. With the recent development of the convolutional neural networks, a significant breakthrough has been made in the classification of remote sensing scenes. Many objects form complex and diverse scenes through spatial combination and association, which makes it difficult to classify remote sensing image scenes. The problem of insufficient differentiation of feature representations extracted by Convolutional Neural Networks (CNNs) still exists, which is mainly due to the characteristics of similarity for inter-class images and diversity for intra-class images. In this paper, we propose a remote sensing image scene classification method via Multi-Branch Local Attention Network (MBLANet), where Convolutional Local Attention Module (CLAM) is embedded into all down-sampling blocks and residual blocks of ResNet backbone. CLAM contains two submodules, Convolutional Channel Attention Module (CCAM) and Local Spatial Attention Module (LSAM). The two submodules are placed in parallel to obtain both channel and spatial attentions, which helps to emphasize the main target in the complex background and improve the ability of feature representation. Extensive experiments on three benchmark datasets show that our method is better than state-of-the-art methods.


Assuntos
Algoritmos , Tecnologia de Sensoriamento Remoto , Redes Neurais de Computação
3.
IEEE Trans Image Process ; 31: 392-404, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-34874855

RESUMO

RGBT tracking receives a surge of interest in the computer vision community, but this research field lacks a large-scale and high-diversity benchmark dataset, which is essential for both the training of deep RGBT trackers and the comprehensive evaluation of RGBT tracking methods. To this end, we present a La rge- s cale H igh-diversity [Formula: see text]nchmark for short-term R GBT tracking (LasHeR) in this work. LasHeR consists of 1224 visible and thermal infrared video pairs with more than 730K frame pairs in total. Each frame pair is spatially aligned and manually annotated with a bounding box, making the dataset well and densely annotated. LasHeR is highly diverse capturing from a broad range of object categories, camera viewpoints, scene complexities and environmental factors across seasons, weathers, day and night. We conduct a comprehensive performance evaluation of 12 RGBT tracking algorithms on the LasHeR dataset and present detailed analysis. In addition, we release the unaligned version of LasHeR to attract the research interest for alignment-free RGBT tracking, which is a more practical task in real-world applications. The datasets and evaluation protocols are available at: https://github.com/mmic-lcl/Datasets-and-benchmark-code.

4.
J Colloid Interface Sci ; 606(Pt 2): 1333-1339, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34492470

RESUMO

Covalent organic frameworks (COFs) are a new class of porous materials receiving much attention due to their unique characteristics. However, COFs have been usually synthesized under harsh and complicated conditions, limiting their practical applications. We propose a surfactant-free strategy to controllably synthesize an imine-based covalent organic framework (COF) nanomaterial in water at room temperature. Introduction of tiny amounts of co-solvents not only achieves the morphology and size control of COFs but also ensures stability of COF nanomaterials in aqueous solution. Moreover, water as a solvent plays an important role in the size adjustment of COFs. The surface area of the obtained COFs was approximately 398 m2/g with a pore size distribution of about 2.8 nm. In addition, the COFs displayed a good crystallinity.

5.
Environ Res ; 206: 112588, 2021 Dec 22.
Artigo em Inglês | MEDLINE | ID: mdl-34951991

RESUMO

Solid fuel use is the main source of indoor air pollution, especially in rural areas of developing countries. Nevertheless, the evidence linking indoor solid fuel use and renal function is very limited. Therefore, we investigated the association between indoor solid fuel use and renal function among middle-aged and older adults in rural China. Cystatin C (CysC) concentration of each participant was used to calculate the estimated glomerular filtration rate (eGFR). We used the baseline data to investigate the associations between solid fuel use for cooking and heating and eGFR through a linear-mixed effects model. Then, we applied the generalized linear-mixed effects model with binary distribution to examine the relationship between renal function decline and cooking fuel switching from 2011 to 2015. A total of 4959 participants were included at baseline, and 3536 participants were included in the follow-up analysis. Compared to participants who used clean fuel for both cooking and heating, the eGFR was significantly lower among participants who cooked with solid fuel and heated with clean fuel (ß: -2.81; 95% CI: -5.53, -0.09). In the follow-up analysis, the risks of renal function decline for participants using solid fuel for cooking were significantly higher in males (OR: 2.74; 95% CI: 1.68, 4.49), smokers (OR: 5.70; 95% CI: 2.82, 11.55), and drinkers (OR: 7.11; 95% CI: 3.15, 16.02) compared to females, non-smokers, and non-drinkers. Moreover, 45-65 years aged participants (OR: 0.54; 95% CI: 0.33, 0.89) and non-drinkers (OR: 0.61; 95% CI: 0.41, 0.92) who switched from solid to clean cooking fuel had a lower risk of renal function decline. In conclusion, our findings show that household solid fuel use is likely to be an important risk factor for renal function decline in rural China. And switching to cleaner fuel may provide significant public health benefits.

6.
PeerJ Comput Sci ; 7: e802, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34909466

RESUMO

Massive plant hyperspectral images (HSIs) result in huge storage space and put a heavy burden for the traditional data acquisition and compression technology. For plant leaf HSIs, useful plant information is located in multiple arbitrary-shape regions of interest (MAROIs), while the background usually does not contain useful information, which wastes a lot of storage resources. In this paper, a novel hyperspectral compressive sensing framework for plant leaves with MAROIs (HCSMAROI) is proposed to alleviate these problems. HCSMAROI only compresses and reconstructs MAROIs by discarding the background to achieve good reconstructed performance. But for different plant leaf HSIs, HCSMAROI has the potential to be applied in other HSIs. Firstly, spatial spectral decorrelation criterion (SSDC) is used to obtain the optimal band of plant leaf HSIs; Secondly, different leaf regions and background are distinguished by the mask image of the optimal band; Finally, in order to improve the compression efficiency, after discarding the background region the compressed sensing technology based on blocking and expansion is used to compress and reconstruct the MAROIs of plant leaves one by one. Experimental results of soybean leaves and tea leaves show that HCSMAROI can achieve 3.08 and 5.05 dB higher PSNR than those of blocking compressive sensing (BCS) at the sampling rate of 5%, respectively. The reconstructed spectra of HCSMAROI are especially closer to the original ones than that of BCS. Therefore, HCSMAROI can achieve significantly higher reconstructed performance than that of BCS. Moreover, HCSMAROI can provide a flexible way to compress and reconstruct different MAROIs with different sampling rates, while achieving good reconstruction performance in the spatial and spectral domains.

7.
JAMA Netw Open ; 4(12): e2141089, 2021 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-34964852

RESUMO

Importance: Little is known about the incidence and outcomes of Clostridioides difficile infection (CDI) in solid organ transplant (SOT) recipients. Objective: To estimate the CDI incidence and outcomes in SOT recipients. Design, Setting, and Participants: A population-based cohort study was conducted using administrative health care data for all Ontario, Canada, residents who received organ allografts from April 1, 2003, to December 31, 2017; March 31, 2020, was the end of the study period. Main Outcomes and Measures: The primary outcome was hospital admission with CDI diagnosis. The secondary outcomes included all-cause death, intensive care unit admission, acute kidney injury requiring dialysis, and fulminant CDI comprising any of the following: toxic megacolon, ileus, perforation, or colectomy. The association between short- vs long-term mortality (ie, death occurring within or after 90 days post-CDI) and the following variables was evaluated: age, sex, Deyo-Charlson Comorbidity Index, SOT type, early- vs late-onset CDI, fulminant CDI, intensive care unit admission, and acute kidney injury requiring acute dialysis. Results: Overall, 10 724 SOT recipients (6901 [64.4%] men; median age, 54 [IQR, 44-62] years) were eligible. Kidney transplant was the most common SOT type (6453 [60.2%]). The median follow-up time was 5.0 (IQR, 2.3-8.8) years, resulting in 61 987 person-years of follow-up. A total of 726 patients (6.8%) were hospitalized with CDI. The 1-year CDI incidence significantly increased in annual cohorts (ie, from 23.1; 95% CI, 12.8-41.8 per 1000 person-years in 2004 to 46.7; 95% CI, 35.0-62.3 per 1000 person-years in 2017; P = .001). Clostridioides difficile was associated with a 16.8% rate (n = 122) of 90-day mortality. In patients who underwent kidney transplant, CDI was typically late-onset (median interval, 2.2; IQR, 0.4-6.0 years) compared with recipients of other organs. Acute kidney injury requiring dialysis was significantly associated with short-term (adjusted odds ratio [aOR], 1.86; 95% CI, 1.07-3.26) and long-term (adjusted hazard ratio [aHR], 1.89; 95% CI, 1.29-2.78) mortality, and late-onset CDI was also significantly associated with a greater risk of short-term (aOR, 4.26; 95% CI, 2.51-7.22) and long-term (aHR, 2.49; 95% CI, 1.78-3.49) mortality. Conclusions and Relevance: In this study, increasing CDI trends in annual cohorts of SOT recipients were observed. Posttransplant CDI was associated with mortality, and late-onset CDI was associated with a greater risk of death than early-onset CDI. These findings suggest that preventive strategies should not be limited to the initial months following transplantation. Comprehensive therapeutic approaches targeting acute kidney injury risk factors in SOT recipients may reduce short- and long-term post-CDI mortality.


Assuntos
Infecções por Clostridium/epidemiologia , Transplante de Órgãos , Adulto , Infecções por Clostridium/etiologia , Infecções por Clostridium/mortalidade , Estudos de Coortes , Feminino , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Ontário/epidemiologia , Modelos de Riscos Proporcionais , Fatores de Risco , Adulto Jovem
8.
Clin Cancer Res ; 2021 Dec 29.
Artigo em Inglês | MEDLINE | ID: mdl-34965953

RESUMO

PURPOSE: CALGB 90206 was a phase III trial of 732 patients with metastatic renal cell carcinoma (mRCC) comparing bevacizumab plus IFNα (BEV + IFN) with IFNα alone (IFN). No difference in overall survival (OS) was observed. Baseline samples were analyzed to identify predictive biomarkers for survival benefit. PATIENTS AND METHODS: A total of 32 biomarkers were assessed in 498 consenting patients randomly assigned into training (n = 279) and testing (n = 219) sets. The proportional hazards model was used to test for treatment arm and biomarker interactions of OS. The estimated coefficients from the training set were used to compute a risk score for each patient and to classify patients by risk in the testing set. The resulting model was assessed for predictive accuracy using the time-dependent area under the ROC curve (tAUROC). RESULTS: A statistically significant three-way interaction between IL6, hepatocyte growth factor (HGF), and bevacizumab treatment was observed in the training set and confirmed in the testing set (P < 0.0001). The model based on IL6, HGF, and bevacizumab treatment was predictive of OS (P < 0.001), with the high- and low-risk groups having a median OS of 10.2 [95% confidence interval (CI), 8.0-13.8] and 34.3 (95% CI, 28.5-40.5) months, respectively. The average tAUROC for the final model of OS based on 100 randomly split testing sets was 0.78 (first, third quartiles = 0.77, 0.79). CONCLUSIONS: IL6 and HGF are potential predictive biomarkers of OS benefit from BEV + IFN in patients with mRCC. The model based on key biological and clinical factors demonstrated predictive efficacy for OS. These markers warrant further validation in future anti-VEGF and immunotherapy in mRCC trials.

9.
Pain Res Manag ; 2021: 5329881, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34840636

RESUMO

Objective: This study aimed to use multidimensional musculoskeletal ultrasound imaging technique to investigate the effect of electroacupuncture (EA) on shoulder subluxation in poststroke patients with hemiplegic shoulder pain. Methods: In this prospective single-blind, randomized, sham-controlled study, thirty-four patients with shoulder subluxation and hemiplegic shoulder pain were recruited and randomly assigned into the EA group or the sham EA (SEA) group. In the EA group, EA was applied to the Jian yu (LI15), Bi nao (LI14), Jian zhen (SI9), and Jian liao (TE14) acupoints. In the SEA group, the EA was applied 15 mm away from the Lou gu (SP7), Di ji (SP8), Jiao xin (KI8), and Zhu bin (KI9) acupoints. Both groups underwent treatment 30 minutes/day, five days a week, for two weeks using dense waves with a frequency of 2/100 Hz. A Visual Analogue Scale (VAS) was used to evaluate the effectiveness of treatment in reducing shoulder pain. Musculoskeletal ultrasound was used to evaluate the changes of measures of shoulder subluxation in multidimensions (i.e., the acromiohumeral distance, AHD; acromion-greater tuberosity, AGT; and acromion-lesser tuberosity, ALT). Both the within- and between-groups treatment effects were assessed. Results: The pain intensity measured by VAS and shoulder subluxation measured by musculoskeletal ultrasound (i.e., AHD, AGT, and ALT) showed significant (p < 0.05) within-group difference in both groups. The between-group difference appeared in the pain intensity (p < 0.05), while it disappeared in the three measures of shoulder subluxation (p > 0.05). Conclusions: Using VAS for measuring pain intensity and multidimensional musculoskeletal ultrasound imaging technique for measuring shoulder subluxation, this study finds that the hemiplegic shoulder pain can be improved significantly by the EA while the shoulder subluxation cannot be. Our findings further reveal the analgesic mechanism of EA on hemiplegic shoulder pain following stroke.

10.
Artigo em Inglês | MEDLINE | ID: mdl-34818467

RESUMO

OBJECTIVE: To explore the safety and feasibility of thoracoscopic surgery in patients with lung cancer under non-intubation anesthesia, and to evaluate the advantages of the non-intubation anesthesia compared with intubation anesthesia on enhanced recovery after surgery (ERAS). METHODS: A retrospective cohort study was conducted in which 100 patients who underwent thoracoscopic lung cancer surgery from January 2020 to February 2021 in the Department of Thoracic Surgery of the First Affiliated Hospital of Soochow University were included and divided into non-intubation group (n = 50) and intubation group (n = 50). The primary outcome was the comparison of intra- and postoperative parameters. Secondary outcomes included inflammatory response indicators and intra- and postoperative complications. RESULTS: There was no significant difference between the two groups in anesthesia effect score, blood loss, lowest pulse oxygen saturation, operation time, postoperative chest tube indwelling time (P > 0.05). Non-intubation group had less intraoperative remifentanil dosage, less change of blood pressure and heart rate, lower postoperative pain numerical score(NRS), less medical costs, smaller incidence rate of throat discomfort (P < 0.05). The non-intubation group was also associated with less extubation time, postanesthesia care unit recovery time, ambulation time, food intake time, postoperative antibiotic use time, and hospital stay (P < 0.05). The increase of C-reactive protein in the non-intubation group was lower than that in the intubation group (P < 0.05). CONCLUSION: Non-intubation anesthesia for thoracoscopic lung cancer surgery is safe and feasible. Compared with the intubation anesthesia, it has advantages in ERAS and reducing medical costs.

11.
ACS Appl Mater Interfaces ; 13(46): 54665-54676, 2021 Nov 24.
Artigo em Inglês | MEDLINE | ID: mdl-34762403

RESUMO

Highly efficient enrichment of phosphopeptides is of great significance for phosphoproteomics-related biological and pathological processes research, but it remains challenging due to the lack of affinity materials which hold high enrichment efficiency and capacity. Ti3C2Tx MXene, a novel two-dimensional material with outstanding physicochemical properties, has attracted wide research interests for application in various fields. However, there are few reports on the use of MXene-derived materials for phosphopeptides separation in the biomedical field. In this work, we proposed a facile one-pot method that in situ oxidation and modification of Ti3C2Tx MXene, to prepare two-dimensional (2D) magnetic Fe3O4/TiO2@Ti3C2Tx composites for potential application in phosphopeptides enrichment. Benefiting from the outstanding magnetic responsiveness and multiaffinity sites (Ti-O, Fe-O, and NH2 groups), the Fe3O4/TiO2@Ti3C2Tx composites possessed excellent enrichment performance with high sensitivity (0.1 fmol µL-1), excellent selectivity (ß-casein: bovine serum albumin = 1:5000, molar ratio), good repeatability (5 times), and high enrichment capacity (200 mg g-1). Moreover, the results of selective enrichment of phosphopeptides from nonfat milk, human saliva, human serum, and rat brain lysates indicated the great potential of Fe3O4/TiO2@Ti3C2Tx composites in low-abundance phosphopeptides enrichment from complex biological samples. This work has put forward a versatile method to prepare magnetic MXene composites and promoted the use of MXene composites in phosphoproteome in biomedicine.

12.
Opt Express ; 29(23): 38841-38848, 2021 Nov 08.
Artigo em Inglês | MEDLINE | ID: mdl-34808927

RESUMO

When insufficient samples in the spatial frequency domain could be effectively compensated by the modified CLEAN algorithm, a novel aperture-synthetic scheme of ghost imaging takes advantage of a superior speed of modulation and an enhancement on the spatial resolution. However, there still exist some imperfections in the modified CLEAN reconstructions, such as the fact that some omitted scatter noise still remains or the object contour may be incomplete. Therefore, we optimize the modified CLEAN algorithm by proposing a density clustering algorithm to overcome these drawbacks and improve the visual quality.

13.
Opt Express ; 29(21): 33926-33936, 2021 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-34809193

RESUMO

The measurement accuracy of a Brillouin optical time domain analysis (BOTDA) fiber sensor is determined by the signal-to-noise ratio (SNR) of the received sensing signal. Here, a new hybrid aperiodic coding method is proposed to improve the SNR. In the proposed method, two pre-discovered short seed aperiodic codes (SA-codes) are used to construct a new hybrid aperiodic code (HA-code) in a nested way. The HA-code inherits the good denoising capabilities of the two SA-codes and features a high coding gain. In the proof-of-concept experiment, a SNR improvement up to 8 dB is obtained, which improves the measurement certainty to 1.67 MHz over a 117.46 km sensing range under a spatial resolution of 2.6 m.

16.
J Diabetes Investig ; 2021 Nov 19.
Artigo em Inglês | MEDLINE | ID: mdl-34797962

RESUMO

We report the findings of a single-dose, randomized, three-period crossover, clinical trial in healthy Chinese individuals (n=24) comparing the pharmacokinetics of insulin degludec/liraglutide (IDegLira) with its individual components. Furthermore, we report a population pharmacokinetic analysis of a 26-week, phase 3, treat-to-target, randomized trial of 720 Chinese individuals with type 2 diabetes. Participants were randomized to IDegLira, degludec or liraglutide, all once daily with metformin. The pharmacokinetic profiles of IDegLira were similar to its individual components. Dose proportionality was indicated for both IDegLira components. While there were no relevant covariate effects on degludec exposure, liraglutide exposure was inversely correlated with body weight. In conclusion, for the Chinese population, the pharmacokinetics of the fixed-ratio combination IDegLira is similar to that of its individual components.

17.
Opt Lett ; 46(22): 5537-5540, 2021 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-34780397

RESUMO

Camera calibration tends to suffer from the low-quality target image acquisition, which would yield inaccurate or inadequate extracted features, resulting in imprecise or even failed parameter estimation. To address this problem, this Letter proposes a novel deep-learning-based adaptive calibration method robust to defocus and noise, which could significantly enhance the image quality and effectively improve the calibration result. Our work provides a convenient multi-quality target dataset generation strategy and introduces a multi-scale deep learning framework that successfully recovers a sharp target image from a deteriorated one. Free from capturing additional patterns or using special calibration targets, the proposed method allows for a more reliable calibration based on the poor-quality acquired images. In this study, an initial training dataset can be easily established containing only 68 images captured by a smartphone. Based on the augmented dataset, the superior performance and flexible transferable ability of the proposed method are validated on another camera in the calibration experiments.

18.
Opt Lett ; 46(21): 5372-5375, 2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34724478

RESUMO

As a new, to the best of our knowledge, alternative to the saturated vapor-cell-based Faraday anomalous dispersion optical filter (FADOF), the FADOF based on a hollow cathode lamp (HCL-FADOF) not only enables the FADOF to work normally at room temperature without heating, but also has some new features due to the inherent characteristics of the HCL. In this Letter, we implement an HCL-FADOF operating on the rubidium D2 line and experimentally investigate the effect of ambient temperature on its performance and cold-start characteristics. Results show that the HCL-FADOF can provide excellent stability within a large temperature range, even at temperatures below 0°C. A comparison of the start performance between the HCL-FADOF and FADOF using saturated vapor cells is also provided. This work shows unique features of the HCL-FADOF in a low-temperature environment and its quick-start advantage, which provides a solid foundation for extensive applications.

19.
Front Neurol ; 12: 675917, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34603179

RESUMO

Background and Purpose: The utilization of flow diversion for ruptured intracerebral aneurysms (IAs) is still limited. We aimed to demonstrate our multicenter experience using the pipeline embolization device (PED) for ruptured IAs that were difficult to treat by clipping and coiling. Methods: Thirty-eight patients with ruptured IAs who underwent PED treatment from 2015 to 2020 were retrospectively reviewed. Factors associated with procedure-related stroke (ischemic and hemorrhagic) and clinical and angiography outcomes were analyzed. Results: There were 14 (36.8%) saccular IAs, 12 (31.6%) blister-like IAs, and 12 (31.6%) dissecting IAs. Perforator involvement was noted in 10 (26.3%) IAs. Early PED placement ( ≤ 15 days) and adjunctive coiling treatment were performed in 27 (71.1%) and 22 (57.9%) cases, respectively. The overall rate of stroke-related complications was 31.6% (12/38) (including rates of 10.5% for procedure-related hemorrhagic complications and 15.8% for procedure-related infarction). The mortality rate was 13.2% (5/38), and 84.2% of patients (32/38) had favorable outcomes. Thirty-two (84.2%) patients underwent follow-up angiographic evaluations; of these, 84.4% (27 patients) had complete occlusion and 15.6% had incomplete obliteration. Multivariate analysis revealed that early PED placement was not associated with a high risk of procedure-related stroke or an unfavorable outcome. Adjunctive coiling exhibited an association with procedure-related stroke (p = 0.073). Procedure-related hemorrhagic complications were significantly associated with an unfavorable outcome (p = 0.003). Immediate contrast stasis in the venous phase was associated with complete occlusion during follow-up (p = 0.050). Conclusion: The PED is a feasible and effective treatment to prevent rebleeding and achieve aneurysm occlusion, but it is associated with a substantial risk of periprocedural hemorrhage and ischemic complications in acute ruptured IAs. Therefore, the PED should be used selectively for acutely ruptured IAs. Additionally, adjunctive coiling might increase procedure-related stroke; however, it may reduce aneurysm rebleeding in acutely ruptured IAs. Patients with immediate contrast stasis in the venous phase were more likely to achieve total occlusion. A prospective study with a larger sample size should be performed to verify our results.

20.
Opt Express ; 29(20): 32333-32348, 2021 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-34615307

RESUMO

Highly reliable wireless train-ground communication immune to the electromagnetic interferences (EMIs) is of critical importance for the security and efficiency of high-speed railways (HSRs). However, the rapid development of HSRs (>52,000 km all over the world) brings great challenges on the conventional EMIs mitigation strategies featuring non-real-time and passive. In this paper, the convergence of radio-over-fiber distributed antenna architecture (RoF-DAA) and reinforcement learning technologies is explored to empower a real-time, cognitive and efficient wireless communication solution for HSRs, with strong immunity to EMIs. A centralized communication system utilizes the RoF-DAA to connect the center station (CS) and distributed remote radio units (RRUs) along with the railway track-sides to collect electromagnetic signals from environments. Real-time recognition of EMIs and interactions between the CS and RRUs are enabled by the RoF link featuring broad bandwidth and low transmission loss. An intelligent proactive interference avoidance scheme is proposed to perform EMI-immunity wireless communication. Then an improved Win or learn Fast-Policy Hill Climbing (WoLF-PHC) multi-agent reinforcement learning algorithm is adopted to dynamically select and switch the operation frequency bands of RRUs in a self-adaptive mode, avoiding the frequency channel contaminated by the EMIs. In proof-of-concept experiments and simulations, EMIs towards a single RRU and multiple RRUs in the same cluster and towards two adjacent RRUs in distinct clusters are effectively avoided for the Global System for Mobile communications-Railway (GSM-R) system in HSRs. The proposed system has a superior performance in terms of circumventing either static or dynamic EMIs, serving as an improved cognitive radio scheme to ensuring high security and high efficiency railway communication.

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