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3.
Heliyon ; 10(7): e29061, 2024 Apr 15.
Article in English | MEDLINE | ID: mdl-38596060

ABSTRACT

CRISPR/Cas9 possesses the most promising prospects as a gene-editing tool in post-genomic researches. It becomes an epoch-marking technique for the features of speed and convenience of genomic modification. However, it is still unclear whether CRISPR/Cas9 gene editing can cause irreversible damage to the genome. In this study, we successfully knocked out the WHITE gene in Drosophila, which governs eye color, utilizing CRISPR/Cas9 technology. Subsequently, we conducted high-throughput sequencing to assess the impact of this editing process on the stability of the entire genomic profile. The results revealed the presence of numerous unexpected mutations in the Drosophila genome, including 630 SNVs (Single Nucleotide Variants), 525 Indels (Insertion and Deletion) and 425 MSIs (microsatellite instability). Although the KO (knockout) specifically occurred on chromosome X, the majority of mutations were observed on chromosome 3, indicating that this effect is genome-wide and associated with the spatial structure between chromosomes, rather than being solely limited to the location of the KO gene. It is worth noting that most of the mutations occurred in the intergenic and intron regions, without exerting any significant on the function or healthy of the animal. In addition, the mutations downstream of the knockout gene well beyond the upstream. This study has found that gene editing can lead to unexpected mutations in the genome, but most of these mutations are harmless. This research has deepened our understanding of CRISPR/Cas9 and broadened its application prospects.

4.
Bioorg Med Chem ; 102: 117656, 2024 Mar 15.
Article in English | MEDLINE | ID: mdl-38422567

ABSTRACT

Urease is the main virulence factor of infectious gastritis and gastric ulcers. Urease inhibitors are regarded as the first choice for the treatment of such diseases. Based on the triazolone/oxadiazolone skeleton, a urea-like fragment being able to specifically bind the urease activity pocket and prevent urea from hydrolysis, we designed and synthesized 45 triazolones/oxadiazolones as urease inhibitors. Eight compounds were proved to show excellent inhibitory activity against Helicobacter pylori urease, being more potency than the clinically used urease inhibitor acetohydroxamic acid. The most active inhibitor with IC50 value of 1.2 µM was over 20-fold higher potent than the positive control. Enzymatic kinetic assays showed that these novel inhibitors reversibly inhibited urease with a mixed competitive mechanism. Molecular dockings provided evidence for the observations in enzyme assays. Furthermore, these novel inhibitors were proved as drug-like compounds with very low cytotoxicity to mammalian cells and favorable water solubility. These results suggested that triazolone and oxadiazolone were promising scaffolds for the design and discovery of novel urease inhibitors, and were expected as good candidates for further drug development.


Subject(s)
Helicobacter pylori , Stomach Ulcer , Animals , Urease , Molecular Docking Simulation , Urea , Enzyme Inhibitors/pharmacology , Mammals/metabolism
5.
Article in Chinese | WPRIM (Western Pacific) | ID: wpr-1019049

ABSTRACT

Objective To assess the nutritional status of vitamin D and associated factors among adults of six ethnic minority groups native to Yunnan Province,and provide evidence for policy making.Methods Between May 2019 and August 2020,a total of 690 adults were selected from Jinuo,Bulang,Jingpo,Deang,Achang and Pumi ethnic groups according to the sex and age composition in the 6th national census.A questionnaire survey and an anthropometric examination were conducted by trained health workers,and serum 25(OH)D levels were determined with high-performance liquid chromatography-tandem mass spectrometry.Results The median of serum 25(OH)D was 28.7(P25~P75∶24.3~33.8)ng/mL,and the prevalence of vitamin D sufficiency,insufficiency and deficiency were 44.2%、47.5%and 8.3%,respectively.There were significant differences in serum 25(OH)D levels among the six ethnic groups(χ2=139.29,P<0.01).Multivariate logistic regression showed that ethnic groups living in higher latitude areas(Pumi,Jingpo,Deang,and Achang),women,and those whose BMI≥24.0 were more likely to be vitamin D insufficient or deficient.Conclusion More than half of the ethnic adults suffer from vitamin D malnutrition which also varies across ethnicities.Further surveillance and interventions among key areas and populations are needed.

6.
Article in Chinese | WPRIM (Western Pacific) | ID: wpr-1020592

ABSTRACT

Lung cancer is one of the malignant tumors with the highest mortality and the fastest growing incidence,which seriously threatens human life and health.With the popularization of low-dose spiral CT and the enhancement of public awareness of physical examination,more and more ground-glass nodules have been detected.Accumulating studies have shown that for patients with nodules diameter≤2 cm and ground-glass opacity≥50% ,under the condition of ensuring the cutting edge,thoracoscopic sublobectomy or subsegmentectomy can more effectively preserve the lung function of patients,and has gradually become the recommended surgical method.In recent years,with the continuous improvement of thoracoscopic surgery technology,thoracoscopic subsegmentectomy and combined subsegmentectomy have been gradually carried out.Compared with lobectomy and segmentectomy,subsegmental resection can retain more normal lung tissue and reduce the loss of lung function under the condition of ensuring the safe cutting edge.However,thoracoscopic subsegmental resection requires a higher level of surgical technique and anatomical knowledge for the operator,and is rarely reported in relevant literature.Therefore,this article reviews the progress of anatomical subsegmentectomy and combined subsegmentectomy in the treatment of early non-small cell lung cancer.

7.
Chinese Health Economics ; (12): 24-28, 2024.
Article in Chinese | WPRIM (Western Pacific) | ID: wpr-1025238

ABSTRACT

Objective:To construct an evaluation index system of operation quality and effectiveness of compact urban medical groups and provide references for evaluation of compact urban medical groups.Methods:The evaluation index system was constructed by Delphi method,and the weight was determined by analytic hierarchy process.Results:The evaluation index system consisted of 5 primary indexes,12 secondary indexes and 40 tertiary indexes.Providing assessment methods for the construction of medical groups,the evaluation index system is scientific and authoritative.Conclusion:At the initial stage,policy support should be strengthened,innovative governance mechanisms should be explored,and measures such as implementing a community of responsibilities,strengthening information interconnection,and improving profit distribution mechanisms should be taken to gradually promote the construction of close urban medical groups.

9.
BMJ Open ; 13(11): e076476, 2023 11 10.
Article in English | MEDLINE | ID: mdl-37949622

ABSTRACT

INTRODUCTION: ST-segment elevation myocardial infarction (STEMI) with high thrombus burden is associated with a poor prognosis. Manual aspiration thrombectomy reduces coronary vessel distal embolisation, improves microvascular perfusion and reduces cardiovascular deaths, but it promotes more strokes and transient ischaemic attacks in the subgroup with high thrombus burden. Intrathrombus thrombolysis (ie, the local delivery of thrombolytics into the coronary thrombus) is a recently proposed treatment approach that theoretically reduces thrombus volume and the risk of microvascular dysfunction. However, the safety and efficacy of intrathrombus thrombolysis lack sufficient clinical evidence. METHODS AND ANALYSIS: The intrAThrombus Thrombolysis versus aspiRAtion thrombeCTomy during prImary percutaneous coronary interVEntion trial is a multicentre, prospective, open-label, randomised controlled trial with the blinded assessment of outcomes. A total of 2500 STEMI patients with high thrombus burden who undergo primary percutaneous coronary intervention will be randomised 1:1 to intrathrombus thrombolysis with a pierced balloon or upfront routine manual aspiration thrombectomy. The primary outcome will be the composite of cardiovascular death, recurrent myocardial infarction, cardiogenic shock, heart failure readmission, stent thrombosis and target-vessel revascularisation up to 180 days. ETHICS AND DISSEMINATION: The trial was approved by Ethics Committees of China-Japan Friendship Hospital (2022-KY-013) and all other participating study centres. The results of this trial will be published in peer-reviewed journals. TRIAL REGISTRATION NUMBER: NCT05554588.


Subject(s)
Myocardial Infarction , Percutaneous Coronary Intervention , ST Elevation Myocardial Infarction , Thrombosis , Humans , ST Elevation Myocardial Infarction/therapy , Myocardial Infarction/complications , Myocardial Infarction/therapy , Prospective Studies , Thrombosis/etiology , Thrombectomy/methods , Percutaneous Coronary Intervention/methods , Thrombolytic Therapy , Treatment Outcome
10.
BMC Health Serv Res ; 23(1): 1097, 2023 Oct 13.
Article in English | MEDLINE | ID: mdl-37833662

ABSTRACT

BACKGROUND: Non-communicable diseases (NCDs) pose a major challenge to health economic cost and residents' health status. Community health workers (CHWs) are the gatekeeper of primary health care. OBJECTIVE: This study aimed to conduct a situational analysis of current human resource and requirements of NCDs-related training among CHWs in Chengdu with regard to address to understand the suggestions for improvement of challenges and barriers. METHODS: A descriptive online cross-sectional survey was conducted among CHWs (doctors and nurses) from 23 districts and counties in Chengdu. Sociodemographic and NCDs-related variables were collected. Univariate analysis and multiple response analysis were used to describe the characteristics of these variables. RESULTS: 711 doctors and 637 nurses completely responded. There were significant differences among gender, age, educational levels, professional title, working year, type of institution, urban circle and registration in general practice between doctors and nurses (P < 0.001). 60.6% of doctors were female, compared to 98.0% for nurses. 58.2% of doctors held a bachelor's degree compared with 45.4% of nurses, while 48.3% of nurses held a junior college degree compared with 25.7% of doctors. Higher levels of professional title and registration in general practice were found in doctors compared with nurses. The proportions of NCDs' category, NCDs-related roles and tasks, NCDs-related training contents and forms that CHWs have attend and hoped to gain more were significantly different between doctors and nurses (P < 0.001). In general, the proportions in nurses were much lower than those of doctors (P < 0.05). The top five diseases managed by CHWs were hypertension, diabetes, cerebrovascular disease, chronic respiratory diseases and mental diseases. The five most reported roles performed among doctors included the distribution of health education (91.4%), following up (85.9%), establishing archives (71.3%), medicine adjustment (64.7%) and treatment implementation (52.0%). The top three diseases managed by nurses were same with doctors. The top four and five tasks were contact with patients or health services (39.6%) and referral (16.6%) in nurses. Most CHWs had received primary and common diseases-related trainings, but they had few opportunities to study in a tertiary hospital (40.4% in doctors and 20.9% in nurses, respectively), attend domestic academic conferences (26.9% in doctors vs. 9.7% in nurses), and take part in training courses (44.9% in nurses). CHWs hoped that the above-discussed training contents and forms could be provided more in the future. Besides basic skills related trainings, some specific skills related trainings should be strengthened. CONCLUSION: The qualifications in doctors were much better than those of nurses. The roles performed by CHWs in NCDs management are varied form common and frequent disease management to subsequent follow up and supervision. CHWs hope to receive more desired and oriented trainings. There is a need for building capacity of CHWs, optimizing and defining CHWs' role, facilitating postgraduate medical education support and strengthening multidisciplinary collaboration would be effective in NCDs management.


Subject(s)
Hypertension , Noncommunicable Diseases , Humans , Female , Male , Cross-Sectional Studies , Community Health Workers/education , Noncommunicable Diseases/epidemiology , Noncommunicable Diseases/therapy , Workforce
11.
Br J Anaesth ; 131(5): 861-870, 2023 11.
Article in English | MEDLINE | ID: mdl-37684164

ABSTRACT

BACKGROUND: Trials have demonstrated lower rates of acute kidney injury in critically ill patients receiving magnesium supplementation, but they have yielded conflicting results regarding mortality. METHODS: This is a retrospective cohort study based on the MIMIC-IV (Medical Information Mart in Intensive Care-IV) database. Adult critically ill patients with sepsis were included in the analysis. The exposure was magnesium sulfate use during ICU stay. The primary outcome was 28-day all-cause mortality. Propensity score matching (PSM) was conducted at a 1:1 ratio. Multivariable analyses were used to adjust for confounders. RESULTS: The pre-matched and propensity score-matched cohorts included 10 999 and 6052 patients, respectively. In the PSM analysis, 28-day all-cause mortality rate was 20.2% (611/3026) in the magnesium sulfate use group and 25.0% (757/3026) in the no use group. Magnesium sulfate use was associated with lower 28-day all-cause mortality (hazard ratio [HR], 0.70; 95% CI, 0.61-0.79; P<0.001). Lower mortality was observed regardless of baseline serum magnesium status: for hypomagnesaemia, HR, 0.64; 95% confidence interval (CI), 0.45-0.93; P=0.020; for normomagnesaemia, HR, 0.70; 95% CI, 0.61-0.80; P<0.001. Magnesium sulfate use was also associated with lower ICU mortality (odds ratio [OR], 0.52; 95% CI, 0.42-0.64; P<0.001), lower in-hospital mortality (OR, 0.65; 95% CI, 0.55-0.77; P<0.001), and renal replacement therapy (OR, 0.67; 95% CI, 0.52-0.87; P=0.002). A sensitivity analysis using the entire cohort also demonstrated lower 28-day all-cause mortality (HR, 0.62; 95% CI, 0.56-0.69; P<0.001). CONCLUSIONS: Magnesium sulfate use was associated with lower mortality in critically ill patients with sepsis. Prospective studies are needed to verify this finding.


Subject(s)
Magnesium Sulfate , Sepsis , Adult , Humans , Retrospective Studies , Magnesium Sulfate/therapeutic use , Cohort Studies , Magnesium , Critical Illness/therapy , Propensity Score , Sepsis/drug therapy , Intensive Care Units
12.
Article in English | MEDLINE | ID: mdl-37672374

ABSTRACT

In recent years, object localization and detection methods in remote sensing images (RSIs) have received increasing attention due to their broad applications. However, most previous fully supervised methods require a large number of time-consuming and labor-intensive instance-level annotations. Compared with those fully supervised methods, weakly supervised object localization (WSOL) aims to recognize object instances using only image-level labels, which greatly saves the labeling costs of RSIs. In this article, we propose a self-directed weakly supervised strategy (SD-WSS) to perform WSOL in RSIs. To specify, we fully exploit and enhance the spatial feature extraction capability of the RSIs' classification model to accurately localize the objects of interest. To alleviate the serious discriminative region problem exhibited by previous WSOL methods, the spatial location information implicit in the classification model is carefully extracted by GradCAM ++ to guide the learning procedure. Furthermore, to eliminate the interference from complex backgrounds of RSIs, we design a novel self-directed loss to make the model optimize itself and explicitly tell it where to look. Finally, we review and annotate the existing remote sensing scene classification dataset and create two new WSOL benchmarks in RSIs, named C45V2 and PN2. We conduct extensive experiments to evaluate the proposed method and six mainstream WSOL methods with three backbones on C45V2 and PN2. The results demonstrate that our proposed method achieves better performance when compared with state-of-the-arts.

13.
Front Endocrinol (Lausanne) ; 14: 1184190, 2023.
Article in English | MEDLINE | ID: mdl-37469989

ABSTRACT

Objective: Diabetic kidney disease (DKD) has been reported as a main microvascular complication of diabetes mellitus. Although renal biopsy is capable of distinguishing DKD from Non Diabetic kidney disease(NDKD), no gold standard has been validated to assess the development of DKD.This study aimed to build an auxiliary diagnosis model for type 2 Diabetic kidney disease (T2DKD) based on machine learning algorithms. Methods: Clinical data on 3624 individuals with type 2 diabetes (T2DM) was gathered from January 1, 2019 to December 31, 2019 using a multi-center retrospective database. The data fell into a training set and a validation set at random at a ratio of 8:2. To identify critical clinical variables, the absolute shrinkage and selection operator with the lowest number was employed. Fifteen machine learning models were built to support the diagnosis of T2DKD, and the optimal model was selected in accordance with the area under the receiver operating characteristic curve (AUC) and accuracy. The model was improved with the use of Bayesian Optimization methods. The Shapley Additive explanations (SHAP) approach was used to illustrate prediction findings. Results: DKD was diagnosed in 1856 (51.2 percent) of the 3624 individuals within the final cohort. As revealed by the SHAP findings, the Categorical Boosting (CatBoost) model achieved the optimal performance 1in the prediction of the risk of T2DKD, with an AUC of 0.86 based on the top 38 characteristics. The SHAP findings suggested that a simplified CatBoost model with an AUC of 0.84 was built in accordance with the top 12 characteristics. The more basic model features consisted of systolic blood pressure (SBP), creatinine (CREA), length of stay (LOS), thrombin time (TT), Age, prothrombin time (PT), platelet large cell ratio (P-LCR), albumin (ALB), glucose (GLU), fibrinogen (FIB-C), red blood cell distribution width-standard deviation (RDW-SD), as well as hemoglobin A1C(HbA1C). Conclusion: A machine learning-based model for the prediction of the risk of developing T2DKD was built, and its effectiveness was verified. The CatBoost model can contribute to the diagnosis of T2DKD. Clinicians could gain more insights into the outcomes if the ML model is made interpretable.


Subject(s)
Diabetes Mellitus, Type 2 , Diabetic Nephropathies , Humans , Diabetes Mellitus, Type 2/complications , Diabetes Mellitus, Type 2/diagnosis , Retrospective Studies , Bayes Theorem , Diabetic Nephropathies/diagnosis , Diabetic Nephropathies/etiology , Albumins
14.
Nanomaterials (Basel) ; 13(13)2023 Jun 21.
Article in English | MEDLINE | ID: mdl-37446413

ABSTRACT

Copper and iron are the basic metal elements that have attracted much attention in industry. Prussian blue (PB) is a significant class of metal-organic frameworks (MOFs); however, the lack of such linkages between the structure and properties, as well as properties differences, limits their potential applications. In this paper, the Cu-based Prussian blue nanocubes with and without Fe doping were synthesized. With the increasing reaction time, the morphology of the Cu-based Prussian blue nanocubes without Fe doping (PB:Cu NCs) changes from cuboidal to circular, and finally grows back to cuboidal. However, Cu-based Prussian blue nanocubes with Fe doping (PB: CuFe NCs) grow directly from the cube and eventually collapse. The nanocubes show a notable red shift with the tunable spectra from 400 nm to 700 nm. Compared with PB: Cu NCs, the PB: CuFe NCs have higher temperature rise under 808 nm irradiation and better photothermal efficacy. The catalytic efficiency of PB: CuFe NCs changes with the pH and reaches its maximum value of 1.021 mM with a pH of 5.5. The enhanced catalytic reaction by the near-infrared radiation plasmonic photothermal effect is also confirmed. This work highlights the potential of the developed PB: Cu and PB: CuFe NCs for photothermal-enhanced co-catalysis nanomaterials.

15.
Article in English | MEDLINE | ID: mdl-37021901

ABSTRACT

The task of hyperspectral image (HSI) classification has attracted extensive attention. The rich spectral information in HSIs not only provides more detailed information but also brings a lot of redundant information. Redundant information makes spectral curves of different categories have similar trends, which leads to poor category separability. In this article, we achieve better category separability from the perspective of increasing the difference between categories and reducing the variation within category, thus improving the classification accuracy. Specifically, we propose the template spectrum-based processing module from spectral perspective, which can effectively expose the unique characteristics of different categories and reduce the difficulty of model mining key features. Second, we design an adaptive dual attention network from spatial perspective, where the target pixel can adaptively aggregate high-level features by evaluating the confidence of effective information in different receptive fields. Compared with the single adjacency scheme, the adaptive dual attention mechanism makes the ability of target pixel to combine spatial information to reduce variation more stable. Finally, we designed a dispersion loss from the classifier's perspective. By supervising the learnable parameters of the final classification layer, the loss makes the category standard eigenvectors learned by the model more dispersed, which improves the category separability and reduces the rate of misclassification. Experiments on three common datasets show that our proposed method is superior to the comparison method.

16.
Materials (Basel) ; 16(4)2023 Feb 09.
Article in English | MEDLINE | ID: mdl-36837075

ABSTRACT

Cu-9Ni-6Sn alloys have received widespread attention due to their good mechanical properties and resistance to stress relaxation in the electronic and electrical industries. The hot compression deformation behaviors of the Cu-9Ni-6Sn-0.3Mn-0.2Zn alloy were investigated using the Gleeble-3500 thermal simulator at a temperature range of 700-900 °C and a strain rate range of 0.001-1 s-1. The microstructural evolution of the Cu-9Ni-6Sn alloy during hot compression was studied by means of an optical microscope and a scanning electron microscope. The constitutive equation of hot compression of the alloy was constructed by peak flow stress, and the corresponding 3D hot processing maps were plotted. The results showed that the peak flow stress decreased with the increase in the compression temperature and the decrease in the strain rate. The hot deformation activation energy was calculated as 243.67 kJ/mol by the Arrhenius equation, and the optimum deformation parameters for the alloy were 740-760 °C and 840-900 °C with a strain rate of 0.001~0.01 s-1. According to Deform-3D finite element simulation results, the distribution of the equivalent strain field in the hot deformation samples was inhomogeneous. The alloy was more sensitive to the deformation rate than to the temperature. The simulation results can provide a guideline for the optimization of the microstructure and hot deformation parameters of the Cu-9Ni-6Sn-0.3Mn-0.2Zn alloy.

17.
Neural Regen Res ; 18(8): 1777-1781, 2023 Aug.
Article in English | MEDLINE | ID: mdl-36751805

ABSTRACT

Inhibition of Notch1 signaling has been shown to promote astrocyte-derived neurogenesis after stroke. To investigate the regulatory role of Notch1 signaling in this process, in this study, we used a rat model of stroke based on middle cerebral artery occlusion and assessed the behavior of reactive astrocytes post-stroke. We used the γ-secretase inhibitor N-[N-(3,5-diuorophenacetyl)-1-alanyl]-S-phenylglycine t-butylester (DAPT) to block Notch1 signaling at 1, 4, and 7 days after injury. Our results showed that only administration of DAPT at 4 days after stroke promoted astrocyte-derived neurogenesis, as manifested by recovery of white matter fiber bundle integrity on magnetic resonance imaging, which is consistent with recovery of neurologic function. These findings suggest that inhibition of Notch1 signaling at the subacute stage post-stroke mediates neural repair by promoting astrocyte-derived neurogenesis.

18.
Materials (Basel) ; 16(1)2023 Jan 02.
Article in English | MEDLINE | ID: mdl-36614764

ABSTRACT

A Cu-1.79Ti-0.39Cr-0.1Mg (wt.%) alloy was prepared by a vacuum induction melting furnace in a high-purity argon atmosphere. The effects of room temperature rolling and cryogenic rolling on the microstructure, textures, and mechanical properties of the alloy were investigated by means of electron backscatter diffraction, transmission electron microscopy, and X-ray diffraction. The results show that the hardness of the cryogenically rolled alloy is 18-30 HV higher than that of the room temperature rolled alloy at any tested rolling reduction. The yield strength and tensile strength of the alloy cryogenically rolled by 90% reduction are 723 MPa and 796 MPa, respectively. With the increase of rolling reduction, the orientation density of the Cube texture decreases, while the Brass texture increases. The Brass texture is preferred especially during the cryogenic rolling, suggesting that the cross-slip is inhibited at the cryogenic temperature. The dislocation densities of Cu-Ti-Cr-Mg alloy increase significantly during the deformation, finally reaching 23.03 × 10-14 m-2 and 29.98 × 10-14 m-2 after a 90% reduction for the room temperature rolled and cryogenically rolled alloys, respectively. This difference could be attributed to the impediment effect of cryogenic temperature on dynamic recovery and dynamic recrystallization. The cryogenic temperature promotes the formation of the dislocation and the nano-twins, leading to the improvement of the mechanical properties of the alloy.

19.
IEEE Trans Cybern ; 53(4): 2346-2357, 2023 Apr.
Article in English | MEDLINE | ID: mdl-34653012

ABSTRACT

Understanding the private car aggregation effect is conducive to a broad range of applications, from intelligent transportation management to urban planning. However, this work is challenging, especially on weekends, due to the inefficient representations of spatiotemporal features for such aggregation effect and the considerable randomness of private car mobility on weekends. In this article, we propose a deep learning framework for a spatiotemporal attention network (STANet) with a neural algorithm logic unit (NALU), the so-called STANet-NALU, to understand the dynamic aggregation effect of private cars on weekends. Specifically: 1) we design an improved kernel density estimator (KDE) by defining a log-cosh loss function to calculate the spatial distribution of the aggregation effect with guaranteed robustness and 2) we utilize the stay time of private cars as a temporal feature to represent the nonlinear temporal correlation of the aggregation effect. Next, we propose a spatiotemporal attention module that separately captures the dynamic spatial correlation and nonlinear temporal correlation of the private car aggregation effect, and then we design a gate control unit to fuse spatiotemporal features adaptively. Further, we establish the STANet-NALU structure, which provides the model with numerical extrapolation ability to generate promising prediction results of the private car aggregation effect on weekends. We conduct extensive experiments based on real-world private car trajectories data. The results reveal that the proposed STANet-NALU outperforms the well-known existing methods in terms of various metrics, including the mean absolute error (MAE), root mean square error (RMSE), Kullback-Leibler divergence (KL), and R2.

20.
IEEE Trans Cybern ; 53(2): 1039-1050, 2023 Feb.
Article in English | MEDLINE | ID: mdl-34464282

ABSTRACT

Achieving reliable intervehicle positioning is one of the most fundamental elements for many vehicular applications, including collision avoidance and autonomous driving. Vehicle position is generally provided by a global navigation satellite system (GNSS), which unfortunately suffers from inaccuracy to varying degrees in challenging environments, for example, GNSS outages. In this article, a reliable fusion technique, called non-Gaussian Redheffer weighted least squares ( n GRWLSs), is proposed. This new approach highlights the intervehicle positioning estimation in multi-GNSS outage environments, such as complete, partial, and free GNSS pseudorange outages. The proposed method combines, on the one hand, the benefits of the Gaussian dynamical matrix principle and the Redheffer distribution function for the sparse property in complete GNSS pseudorange outages and, on the other hand, the use of the optimal window size to regulate the data flow generated by both the inertial navigation systems (INSs) and GNSS during a partial GNSS pseudorange outage. During the free GNSS pseudorange outage, the process ignores data from the INS, and instead, GNSS pseudorange information alone will be considered to compute the intervehicle positioning information. Consequently, weighted least squares is used as an intervehicle positioning estimator. To address the pseudorange uncommon and INS measurement noises, the generalized error distribution (GED) is used to estimate the non-Gaussian densities. Finally, road-test experiments are implemented to evaluate the consistency of the proposed approach. The experimental results show that the proposed n GRWLS can accurately estimate the intervehicle positioning under various conditions (free, partial, and complete GNSS pseudorange outages).

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