A Simple Route towards High-Concentration Surfactant-Free Graphene Dispersions

A simple solvent exchange method is introduced to prepare high-concentration and surfactant-free graphene liquid dispersion. Natural graphite flakes are first exfoliated into graphene in dimethylformamide (DMF). DMF is then exchanged by terpineol through distillation, relying on their large difference in boiling points. Graphene can then be concentrated thanks to the volume difference between DMF and terpineol. The concentrated graphene dispersions are used to fabricate transparent conductive thin films, which possess comparable properties to those prepared by more complex methods.Comment: 9 pages, 3 figure

First-Shot Unsupervised Anomalous Sound Detection With Unknown Anomalies Estimated by Metadata-Assisted Audio Generation

First-shot (FS) unsupervised anomalous sound detection (ASD) is a brand-new task introduced in DCASE 2023 Challenge Task 2, where the anomalous sounds for the target machine types are unseen in training. Existing methods often rely on the availability of normal and abnormal sound data from the target machines. However, due to the lack of anomalous sound data for the target machine types, it becomes challenging when adapting the existing ASD methods to the first-shot task. In this paper, we propose a new framework for the first-shot unsupervised ASD, where metadata-assisted audio generation is used to estimate unknown anomalies, by utilising the available machine information (i.e., metadata and sound data) to fine-tune a text-to-audio generation model for generating the anomalous sounds that contain unique acoustic characteristics accounting for each different machine types. We then use the method of Time-Weighted Frequency domain audio Representation with Gaussian Mixture Model (TWFR-GMM) as the backbone to achieve the first-shot unsupervised ASD. Our proposed FS-TWFR-GMM method achieves competitive performance amongst top systems in DCASE 2023 Challenge Task 2, while requiring only 1% model parameters for detection, as validated in our experiments.Comment: Submitted to ICASSP 202

Changes in and the association of retinal blood perfusion and retinal nerves in diabetic patients without retinopathy

ObjectiveTo explore intraretinal blood flow perfusion and nerve changes, as well as the correlation between them, in diabetic patients without diabetic retinopathy (NDR).MethodEighty-six NDR patients (86 eyes) who attended the ophthalmology clinic between December 2019 and December 2021 were included. Sixty-four eyes of 64 healthy examined controls in the same period were selected as the control group. The patients underwent routine ophthalmological examination, optical coherence tomography (OCT) and OCT angiography.ResultsThe average thickness, minimum thickness and thickness of each quadrant except for the superior temporal quadrant of the ganglion cell-inner plexiform layer (GCIPL) in the macular area of the affected eyes in the NDR group were lower than that of the tested eyes in the control group (P < 0.05). The average retinal nerve fibre layer (RNFL) thickness of the NDR group and the superior, inferior and nasal quadrants around the optic disc of the affected eyes in the NDR group were lower compared with the tested eyes in the control group (P < 0.001, P = 0.003, P = 0.001, P = 0.009). The mean vessel length density in the parafoveal and perifoveal areas in the NDR group was positively associated with the mean GCIPL thickness in the macular area (ρ = 0.265, ρ = 0.257 and P < 0.001). No blood flow perfusion parameters in the NDR group were correlated with the RNFL thickness of the corresponding quadrant around the optic disc (P > 0.05).ConclusionIn diabetic patients without diabetic retinopathy, the superficial retinal vessel density in the macular area positively correlated with GCIPL thickness, and the superficial retinal vessel density around the optic disc was not correlated with RNFL thickness

Water and sediment quality in Qinghai Lake, China: a revisit after half a century.

Qinghai Lake, situated on the Qinghai-Tibet plateau, is the largest lake in China. In this study, the water and sediment quality were investigated in Qinghai Lake, three sublakes, and five major tributaries. Both Na+ and Cl- were found to be the major ions present in Qinghai Lake and the three sublakes, while Ca2+ and HCO3- dominated the tributaries. Compared with historical data from the 1960s, the concentrations of NH4 (+), NO3 (-), and soluble reactive silica have increased considerably, likely caused by increased human activities in the area. Compared to the historical data, chemical oxygen demand has increased and lake water transparency has decreased, likely related to an increase in nutrient levels. Relatively high concentrations of total nitrogen (TN) and total phosphorus (TP) were observed in Qinghai Lake sediments, although P fraction types and low water concentrations of these two indicate low possibility of transfer into the water column. The ratios of C/N suggest that the organic matter in the sediments are primarily from autochthonous sources. TN and total organic carbon in the sediment cores increased slowly up the core while TP and total inorganic carbon have been fairly constant

Dipeptidyl peptidase-4 inhibitors and risk of heart failure in type 2 diabetes : systematic review and meta-analysis of randomised and observational studies

Objectives To examine the association between dipeptidyl peptidase-4 (DPP-4) inhibitors and the risk of heart failure or hospital admission for heart failure in patients with type 2 diabetes. Design Systematic review and meta-analysis of randomised and observational studies. Data sources Medline, Embase, Cochrane Central Register of Controlled Trials, and ClinicalTrials.gov searched up to 25 June 2015, and communication with experts. Eligibility criteria Randomised controlled trials, non-randomised controlled trials, cohort studies, and case-control studies that compared DPP-4 inhibitors against placebo, lifestyle modification, or active antidiabetic drugs in adults with type 2 diabetes, and explicitly reported the outcome of heart failure or hospital admission for heart failure. Data collection and analysis Teams of paired reviewers independently screened for eligible studies, assessed risk of bias, and extracted data using standardised, pilot tested forms. Data from trials and observational studies were pooled separately; quality of evidence was assessed by the GRADE approach. Results Eligible studies included 43 trials (n=68 775) and 12 observational studies (nine cohort studies, three nested case-control studies; n=1 777 358). Pooling of 38 trials reporting heart failure provided low quality evidence for a possible similar risk of heart failure between DPP-4 inhibitor use versus control (42/15 701 v 33/12 591; odds ratio 0.97 (95% confidence interval 0.61 to 1.56); risk difference 2 fewer (19 fewer to 28 more) events per 1000 patients with type 2 diabetes over five years). The observational studies provided effect estimates generally consistent with trial findings, but with very low quality evidence. Pooling of the five trials reporting admission for heart failure provided moderate quality evidence for an increased risk in patients treated with DPP-4 inhibitors versus control (622/18 554 v 552/18 474; 1.13 (1.00 to 1.26); 8 more (0 more to 16 more)). The pooling of adjusted estimates from observational studies similarly suggested (with very low quality evidence) a possible increased risk of admission for heart failure (adjusted odds ratio 1.41, 95% confidence interval 0.95 to 2.09) in patients treated with DPP-4 inhibitors (exclusively sitagliptin) versus no use. Conclusions The relative effect of DPP-4 inhibitors on the risk of heart failure in patients with type 2 diabetes is uncertain, given the relatively short follow-up and low quality of evidence. Both randomised controlled trials and observational studies, however, suggest that these drugs may increase the risk of hospital admission for heart failure in those patients with existing cardiovascular diseases or multiple risk factors for vascular diseases, compared with no use

Sieve Estimates via Neural Network for Strong Mixing Processes

convergence rate, mixing processes, neural network, sieves estimate,

Isolated Bidirectional DC-DC Converter and System Level Control for EV Charger

An isolated bidirectional DC-DC converter is designed for a dual-output EV charger. Various DC-DC converter topologies are compared, including single-output converters and dual-output converters. Then one suitable topology is selected between the multiport CLLC converter and triple active bridge converter based on the simulation performances for the dual-output EV charger. Meanwhile, an investigation into the voltage regulation for a wide output voltage range is conducted with the research of interleaved buck converters. Finally, the system-level control of the EV charger is designed for different operation modes and the converter is modelled in PLEVS and simulated under different scenarios.Electrical Engineering | Electrical Power Engineerin

Estimation non paramétrique par réseaux de neurones pour des processus et estimation de paramètres de position

CETTE THESE SE COMPOSE DE DEUX PARTIES : LES QUATRE PREMIERS CHAPITRES SONT CONSACRES AU PROBLEME DE L'ESTIMATION NON PARAMETRIQUE PAR RESEAUX DE NEURONES POUR DES PROCESSUS STOCHASTIQUES. LA DEUXIEME PARTIE DE CETTE THESE EST LE CINQUIEME CHAPITRE OU NOUS ETUDIONS L'ESTIMATION DU PARAMETRE DE POSITION. DANS LES DEUXIEME ET TROISIEME CHAPITRES, NOUS ETUDIONS LES PROBLEMES DE L'ESTIMATION DE LA REGRESSION ET DE L'ESTIMATION DES QUANTILES CONDITIONNELS POUR DES PROCESSUS ET -MELANGEANTS PAR RESEAUX DE NEURONES. NOUS UTILISONS UNE TECHNIQUE DE COUPLAGE ET ETABLISSONS D'ABORD DEUX INEGALITES EXPONENTIELLES POUR LA -MELANGEANCE ET L'-MELANGEANCE. A PARTIR DE CES INEGALITES, NOUS PARVENONS A BORNER LE RISQUE INTEGRE DE L'ESTIMATEUR PAR UN INDICE DE RESOLUBILITE. NOUS DONNONS ENFIN LES VITESSES QUADRATIQUES MOYENNES INTEGREES. DANS LE QUATRIEME CHAPITRE, NOUS NOUS INTERESSONS AU PROBLEME D'ESTIMATION PAR SIEVE DANS LE CAS SPECIAL DE RESEAUX DE NEURONE. NOUS ETABLISSONS DES VITESSES DE CONVERGENCE DES ESTIMATEURS POUR DES PROCESSUS STRICTEMENT STATIONNAIRES ET FORTEMENT MELANGEANTS DANS CE CAS. UN RESULTAT SURPRENANT EST QUE NOUS OBTENONS PRESQUE LA MEME VITESSE QUE DANS LE CAS I.I.D. SOUS DES CONDITIONS ASSEZ FAIBLES DE REGULARITE. LE CINQUIEME CHAPITRE SE COMPOSE DE TROIS SECTIONS. LA PREMIERE SECTION S'INTERESSE A L'ESTIMATION DU PARAMETRE DE POSITION DE LA LOI NORMALE ET D'UNE LOI A SYMETRIE SPHERIQUE ET MATRICE DE COVARIANCE INCONNUE. LA DEUXIEME SECTION EST CONSACREE A L'ESTIMATION DE LA MOYENNE DE LOI GAUSSIENNE AVEC LA COVARIANCE INCONNUE SOUS DE CLASSES DE FONCTIONS DE COUT. DANS LA TROISIEME SECTION, NOUS CONSIDERONS LE PROBLEME DE L'ESTIMATION DU PARAMETRE DE POSITION DES LOIS A SYMETRIE SPHERIQUE POUR TOUTE UNE CLASSE DE FONCTION DE COUT. DANS LES TROIS SECTIONS, NOUS PROPOSONS DES ESTIMATEURS QUI DOMINENT L'ESTIMATEUR USUEL.PARIS-BIUSJ-Thèses (751052125) / SudocPARIS-BIUSJ-Mathématiques rech (751052111) / SudocCentre Technique Livre Ens. Sup. (774682301) / SudocSudocFranceF

Mathematical Model and Algorithm for the Reefer Mechanic Scheduling Problem at Seaports

With the development of seaborne logistics, the international trade of goods transported in refrigerated containers is growing fast. Refrigerated containers, also known as reefers, are used in transportation of temperature sensitive cargo, such as perishable fruits. This trend brings new challenges to terminal managers, that is, how to efficiently arrange mechanics to plug and unplug power for the reefers (i.e., tasks) at yards. This work investigates the reefer mechanics scheduling problem at container ports. To minimize the sum of the total tardiness of all tasks and the total working distance of all mechanics, we formulate a mathematical model. For the resolution of this problem, we propose a DE algorithm which is combined with efficient heuristics, local search strategies, and parameter adaption scheme. The proposed algorithm is tested and validated through numerical experiments. Computational results demonstrate the effectiveness and efficiency of the proposed algorithm