Determination Of Threshold Research Articles

The elastic threshold for strain-gradient plasticity, and comparison of theoretical results with experiments

This work continues an earlier study, aimed at determining the threshold of elastic behaviour for specimens at the microscale. Given the size-dependent nature of the response the theory makes use of a model of rate-independent strain-gradient plasticity to establish conditions for lower and upper bounds to the threshold. The model is based on a family of yield or dissipation functions. In the earlier work bounds were established for one member of the family, in which the dissipation depends on the root mean square of the magnitude of plastic strain and its gradient. In this work bounds are derived based on a second alternative, in which the dependence is linear. These two alternatives are most relevant in determining length scales through fits to experimental results. The second aim of this work is to carry out comparisons between the bounds obtained theoretically, with experimental data on initial yielding for torsion tests. The correlations are in some cases reasonable, while in others there are discrepancies. Generally they illustrate the complexities – for example in accurate experimental determination of the elastic threshold, and of the length scale – in predicting aspects of behaviour at the microscale.

Automatic hearing screening for better monitoring of hearing health using the example of the German armed forces

In the present study, the concept of asystematic automated screening of temporary soldiers was evaluated based on the example of the ENT Department of the Bundeswehr Central Hospital Koblenz. From 2014 to 2017, anonymized data of 169individuals were collected from the setting of the Bundeswehr Central Hospital. Included in the data are results from measurements with automated pure-tone audiometry (APTA; e.g., [3]), from measurements with the digit triple test for determination of the speech discrimination threshold in noise (e.g., [20]), and from interviews with questionnaires (Hearing-Dependent Daily Activities [HDDA], e.g., [14]; HearCom questionnaire, e.g., [15]). There was an initial publication from this project evaluating the questionnaires in terms of their suitability for detecting hearing loss [14]. In the following (from March 2015), only the HDDA, which was described as more sensitive, was used for measurements at the hearing screening measurement station. Acomplete run with the three procedures took approximately 22 min. Approximately 17% of the examined participants had abnormal findings in at least one of the procedures at the screening station. The results of the respective methods taken together detect more than any method alone and can be assumed to be complementary. Deviations between APTA with level monitor and manual tone audiometry were within the measurement accuracy. In the range between 1and 4 kHz, hearing thresholds are somewhat underestimated with APTA. The threshold for the HDDA questionnaire with an HDDA sum ≥ 19 was confirmed. Automated hearing screening offers agood opportunity to check hearing ability on aregular basis in astandardized and reliable manner, while keeping personnel requirements low.

Operation safety evaluation system of ship lock based on extension evaluation and combination weighting method

Abstract Ship locks are the most widely used, promising, and important type of navigation structure in the world at present. It is, therefore, crucial to evaluate the operation safety of a ship lock in service. However, the determination of indicator thresholds is challenging. Accordingly, this paper describes the systematic study of the evaluation system of ship lock operation safety. First, the safety accidents of ship locks are counted. According to the rhombic thinking mode (that is, the thinking mode of ‘first divergence and then convergence’), with the help of extenics, a multi-indicator hierarchical indicator system including 5 first-class indicators and 47 second-class indicators for the safety evaluation of ship lock operation is established, and 4 safety evaluation grades are classified: normal, deterioration, early warning, and shutdown. The threshold range of each indicator at each grade is determined individually. Second, based on the idea of multi-factor optimization and integration, the process and the matter-element model of ship lock operation safety evaluation based on extension theory are proposed. Then the weight of the safety indicator is determined by the combination weighting method. The evaluation result is consistent with the actual situation.

Prioritization of Lane-Specific Traffic Jam Detection for Automotive Navigation Framework Utilizing Suddenness Index and Automatic Threshold Determination

Prioritization of Lane-Specific Traffic Jam Detection for Automotive Navigation Framework Utilizing Suddenness Index and Automatic Threshold Determination

Heart Disease Prediction and Treatment Suggestion Using Machine Learning

Disease anticipation systems are the better alternatives, to avoid the human errors in disease diagnosis and also assist in disease interference. Nowadays, the number of heart disease patients is increasing so we need an optimal heart disease prediction and treatment suggestion system. Heart disease dataset preparation, prediction system’s process flow design, process execution and results evaluation are the most common life cycle modules of any heart disease prediction system. Input dataset attributes modeling, attribute risk factor calculation; threshold determination and achieving the high accuracy in disease prediction are the major limitations of the existing heart disease prediction and treatment proposal systems. Keywords: Machine learning, Decision tree, Logistic regression.

Chloride threshold determination of hybrid inhibitor immersed in simulated concrete pore solution

The hybrid inhibitor performs excellently compared to either organic or inorganic inhibitor individually. In the present studies, a fixed amount i.e. 2 wt% l-arginine (LA) and 0.25 wt% trisodium phosphate dodecahydrate (TSPDH) is considered as hybrid inhibitor and its chloride threshold is determined by open circuit potential (OCP), electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PDP) in simulated concrete pore solution and the formed passive films are characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy after 240 h of immersion. The chloride threshold of this hybrid inhibitor is 6 wt% NaCl, i.e., C3 until 216 h of immersion, whereas if the amount is increased, the steel rebar leads to corrode severely. 5 wt% NaCl containing sample, i.e., C2 exhibits the noble OCP, highest impedance, and lowest passive current density attributed to the consumption of all zwitterion and phosphate ions in the formation of P-zwitterion-(Cl)-Fe, zwitterion-(Cl)-Fe and FePO4 complexes with NaCl, whereas lower or higher than this amount of NaCl, the Cl- ions either lesser or greater to be formed these complexes.

IRREGULARITIES IN THE DISPLACEMENT OF THE EARTH’S GEOGRAPHIC POLE AND JERKS IN THE GEOMAGNETIC FIELD

There are presented the results of analysis of some irregularities in the series of displacement coordinates on the Earth’s surface for the geographic North Pole in order to relate them temporally to some global jerks in the geomagnetic field. The calculations were made using the International Earth Rotation and Reference Systems Service (IERS) data on the average daily motions of the North Pole from 1962 to 2021 and the information on global jerks in the geomagnetic field measured by the magnetic observatories throughout the world. The identification and analysis of the irregularities in the pole displacement along the Earth’s surface were performed by the Fourier Method and wavelet methods for time series analysis, methods of fixed threshold determination and minimax analysis of the non-Gaussian noise, phase and pseudo-phase space methods, and stroboscopic methods of construction of Poincare maps.The analysis of local Fourier spectra and wavelet-spectra reveals irregularities in the displacement of the North Pole in the time intervals from 1967.04.09 to 1967.11.30, from 1974.03.29 to 1974.09.12, and from 2005.11.03 to 2006.03.07. It is supposed that energy reconstructions which caused short-term pole deviations from the trajectory and starting to follow its previous trajectory at the return points are related to the specific features of oscillatory interactions in the process of the translational-rotational motion of the Earth’s in the Solar System. The time of marking specific points on graphs of the displacement of the pole along the surface of the Earth in 1967 and 1974 is ahead of global geomagnetic jerk occurrence times.

Procalcitonin for the diagnosis of sepsis in neonates: a diagnostic test accuracy review

Objectives This is a protocol for a Cochrane Review (diagnostic). The objectives are as follows: To evaluate the diagnostic accuracy of procalcitonin in culture proven early‐ or late‐onset neonatal sepsis. Secondary objectives To evaluate the diagnostic accuracy of procalcitonin in all sepsis (including both culture‐proven and culture‐negative early‐ or late‐onset neonatal sepsis). To evaluate the diagnostic accuracy of procalcitonin in all sepsis at the most common threshold ranges used (0.5 to 1 ng/mL and ≥ 2 ng/mL). We plan to investigate heterogeneity with respect to the following covariates if adequate data are available. Timing of sepsis onset: a) EOS (≤ 72 hours), b) LOS (> 72 hours). Maturity of infant: a) term (≥ 37 week gestation) b) preterm gestation (< 37 weeks gestation). Pathogen type: a) bacterial b) fungal. Nature of threshold determination: a) threshold identified a priori b) post‐hoc ascertainment of threshold.

Monocular transcorneal electrical stimulation induces ciliary muscle thickening in contralateral eye

Transcorneal electrical stimulation (TES) is used as therapy for retinal diseases such as retinitis pigmentosa (RP) and was suggested for assessing retinal sensitivity by determining phosphene thresholds, subjective luminance impressions caused by retinal stimulation. Further applications concerned the accommodation process, revealing an improved accommodative amplitude in presbyopic eyes after TES treatment. The respective changes of the ciliary muscle (CM), the structure most important for near vision, during TES are yet unknown. In a pilot study, we aimed to assess whether monocular TES leads to morphological and functional CM changes and whether central accommodation control is affected. Ten healthy, near-emmetropic adults participated in the trial (4 females, age 26.3 ± 3.6 years). Using a wavefront and a stimulus generator, a biphasic square-wave stimulus (2 s positive and 6 s negative amplitude) of 0 μA average current was produced and transferred to the eye by means of a Dawson-Trick & Litzkow electrode. Prior to the stimulation, an individual determination of phosphene thresholds served to define individual TES current amplitudes, which ranged between 60 and 100 μA. Optical coherence tomography (OCT) imaging of the right eye's temporal ciliary muscle was performed before and during ipsi- as well as contralateral monocular TES in randomized order in the morning and afternoon of the same day. During imaging, subjects fixated a target at 4 m distance and refraction was simultaneously recorded via eccentric infrared photorefraction. OCT images were assessed using previously published custom-developed software, allowing the definition of selective CM thickness (CMT) readings, and plotting of continuous CMT profiles along the muscle border. CMT profiles revealed that both stimulations, on the ipsi- and contralateral eye, induced a thickening of the CM compared to the non-stimulated state. The selective CMT readings confirmed a significant increase with ipsi- (31 ± 30 μm; p = 0.010) and contralateral (25 ± 16 μm; p = 0.001) TES. However, refraction during far vision was not significantly affected by either stimulation (ipsilateral [n = 5]: median Δw/-w/o = 0 D; contralateral [n = 7]: Δw/-w/o = 0.13 D). Pupil size on average increased during TES, but without reaching significance (ipsilateral [n = 5] median Δw/-w/o = 0.23 mm, contralateral [n = 7] Δw/-w/o = 0.39 mm). Ipsilateral CM thickening could be explained by local changes within the stimulated ciliary muscle, such as increased blood flow or interstitial fluid rise induced by TES. However, the CMT increase in the right eye when TES was performed contralaterally, on the left eye, indicates an involvement of the central control circuit of accommodation. Further possible explanations for this finding are a synchronization of neuronal activities in the visual pathway, the release of vasoactive neuropeptides, or effects on the central blood pressure regulation. Given a neuromodulation effect on the CM function, TES might have implications for children with accommodation insufficiencies and as additional therapy in myopia control management, e.g. in combination with multifocal contact lens treatment. Our study is important for the clinical application of TES, and the outcome might add crucial knowledge to the current understanding of the accommodation process and inform research and treatment of both myopia and presbyopia.

Expanding the clinical application of the polycystic liver disease questionnaire: determination of a clinical threshold to select patients for therapy

BackgroundPolycystic liver disease (PLD) causes symptoms resulting from cystic volume expansion. The PLD-specific questionnaire (PLD-Q) captures symptom burden. This study aims to develop a threshold to identify patients with symptoms requiring further exploration and possibly intervention. MethodsWe recruited PLD patients with completed PLD-Qs during their patient journey. We evaluated baseline PLD-Q scores in (un)treated PLD patients to determine a threshold of clinical importance. We assessed our threshold's discriminative ability with receiver operator characteristic statistics, Youden Index, sensitivity, specificity, positive and negative predictive value parameters. ResultsWe included 198 patients with a balanced proportion of treated (n=100) and untreated patients (n=98, PLD-Q scores 49 vs 19, p<0.001; median total liver volume 5827 vs 2185 ml, p<0.001). We established the PLD-Q threshold at 32 points. A score of ≥32 differentiates treated from untreated patients with an area under the ROC of 0.856, Youden Index 0.564, sensitivity of 85.0%, specificity of 71.4%, positive predictive value of 75.2%, and negative predictive value of 82.4%. Similar metrics were observed in predefined subgroups and an external cohort. ConclusionWe established the PLD-Q threshold at 32 points with high discriminative ability to identify symptomatic patients. Patients with a score ≥32 should be eligible for treatment or inclusion in trials.

No Evidence for Cognitive Impairment in an Experimental Rat Model of Knee Osteoarthritis and Associated Chronic Pain

Although chronic pain states have been associated with impaired cognitive functions, including memory and cognitive flexibility, the cognitive effects of osteoarthritis (OA) pain remain to be clarified. The aim of this study was to measure cognitive function in the mono-iodoacetate (MIA) rat model of chronic OA-like knee pain. We used young adult male Lister hooded rats, which are well-suited for cognitive testing. Rats received either a unilateral knee injection of MIA (3 mg/50 µL) or saline as control. Joint pain at rest was assessed for up to 12 weeks, using weight-bearing asymmetry, and referred pain at a distal site, using determination of hindpaw withdrawal thresholds. The watermaze delayed-matching-to-place test of rapid place learning, novel object recognition memory assay, and an operant response-shift and -reversal task were used to measure memory and behavioral flexibility. Open-field locomotor activity, startle response, and prepulse inhibition were also measured for comparison. MIA-injected rats showed markedly reduced weight-bearing on the injured limb, as well as pronounced cartilage damage and synovitis, but interestingly no changes in paw withdrawal threshold. Rearing was reduced, but otherwise, locomotor activity was normal and no changes in startle and prepulse inhibition were detected. MIA-injected rats had intact watermaze delayed-matching-to-place performance, suggesting no substantial change in hippocampal function, and there were no changes in novel object recognition memory or performance on the operant task of behavioral flexibility. Our finding that OA-like pain does not alter hippocampal function, unlike other chronic pain conditions, is consistent with human neuroimaging findings. PerspectiveYoung adult rats with OA-like knee pain showed no impairments in hippocampal memory function and behavioral flexibility, suggesting that OA pain impacts cognitive functions less than other chronic pain conditions. In patients, OA pain may interact with other factors (e.g., age, socio-economic factors, and medication) to impair cognition.

Behavioral and functional assessment of mice inner ear after chronic exposure to an ultrahigh B0 field of 11.7 T or 17.2 T.

Assess short-term and long-term effects of chronic exposure to an ultrahigh static magnetic (B0 ) field on mice inner ear in the context of MR safety of human scanning at 11.7 T. Mice were chronically exposed to a B0 field of 11.7 T or 17.2 T during ten 2-h exposure sessions evenly distributed over a period of 5 weeks, resulting in a total of 20 h of exposure per mouse. During exposure sessions, mice were anesthetized and positioned either parallel or antiparallel to B0 . Before, during, and 2 weeks after the magnetic-field exposure period, mice performed behavioral tests (balance beam, rotarod, and swim tests) to evaluate their short-term and long-term motor coordination and balance. An auditory brainstem response (ABR) test was finally performed to assess the functional integrity of mice cochlea, 2 weeks after the last exposure. After awaking from anesthesia following B0 exposures at 11.7 Tor 17.2 T, mice displayed a transient (<5 min) rotating behavior. The behavioral tests did not show any difference between the exposed and the control mice at any time point. Determination of ABR thresholds did not reveal an impairment of cochlea hair cells resulting from chronic B0 exposure. Despite the transient disturbance of mice vestibular system observed immediately after B0 exposure, no short-term nor long-term alteration was detected with behavioral and ABR tests.

From Meaningful Outcomes to Meaningful Change Thresholds: A Path to Progress for Establishing Digital Endpoints.

This paper examines the use of digital endpoints (DEs) derived from digital health technologies (DHTs), focusing primarily on the specific considerations regarding the determination of meaningful change thresholds (MCT). Using DHTs in drug development is becoming more commonplace. There is general acceptance of the value of DHTs supporting patient-centric trial design, capturing data outside the traditional clinical trial setting, and generating DEs with the potential to be more sensitive to change than conventional assessments. However, the transition from exploratory endpoints to primary and secondary endpoints capable of supporting labeling claims requires these endpoints to be substantive with reproducible population-specific values. Meaningful change represents the amount of change in an endpoint measure perceived as important to patients and should be determined for each digital endpoint and given population under consideration. This paper examines existing approaches to determine meaningful change thresholds and explores examples of these methodologies and their use as part of DE development: emphasizing the importance of determining what aspects of health are important to patients and ensuring the DE captures these concepts of interest and aligns with the overarching endpoint strategy. Examples are drawn from published DE qualification documentation and responses to qualification submissions under review by the various regulatory authorities. It is the hope that these insights will inform and strengthen the development and validation of DEs as drug development tools, particularly for those new to the approaches to determine MCTs.

Integrating additional spectroscopically inferred soil data improves the accuracy of digital soil mapping

Digital soil mapping has been increasingly advocated as an efficient approach to deliver fine-resolution and up-to-date soil information in evaluating soil ecosystem services. Considering the great spatial heterogeneity of soils, it is widely recognized that more representative soil observations are needed for better capturing the soil spatial variation and thus to increase the accuracy of digital soil maps. In reality, the budget for the field work and soil laboratory analysis is commonly limited due to its high cost and low efficiency. In the last two decades, being an alternative to wet chemistry, soil spectroscopy, such as visible-near infrared (Vis-NIR), mid-infrared (MIR) spectroscopy has been developed in measuring soil information in a rapid and cost-effective manner and thus enable to collect more soil information for digital soil mapping (DSM). However, spectroscopically inferred (SI) data are subject to higher uncertainties than reference laboratory analysis. Many DSM practices integrated SI data with soil observations into spatial modelling while few studies addressed the key question that whether these non-errorless soil data improve map accuracy in DSM. In this study, French Soil Monitoring Network (RMQS) and Land Use and Coverage Area frame Survey Soil (LUCAS Soil) datasets were used to evaluate the potential of SI data from Vis-NIR and MIR in digital mapping of soil properties (i.e. soil organic carbon, clay, and pH) at a national scale. Cubist and quantile regression forests were used for spectral predictive modelling and DSM modelling, respectively. For both RMQS and LUCAS Soil dataset, different scenarios regarding varying proportions of SI data and laboratory observations were tested for spectral predictive models and DSM models. Repeated (50 times) external validation suggested that adding additional SI data can improve the performance of DSM models regardless of soil properties (gain of R2 proportion at 3–19%) when the laboratory observations are limited (≤50%). Lower proportion of SI data used in DSM model and higher accuracy of spectral predictive models led to greater improvement of DSM. Our results also showed that a greater proportion of SI data lowered the prediction intervals which may result in an underestimation of prediction uncertainty. The determination of accuracy threshold on SI data for the use in DSM needs to be explored in future studies.

Evaluation of a new complement-dependent lymphocytotoxicity cross match method using an automated cell counter, the NucleoCounter® NC-3000™.

Complement-dependent lymphocytotoxicity cross match (CDC-XM) is the ultimate test of donor/recipient compatibility prior to organ transplantation. This test is based on cell viability, evaluated under fluorescence microscopy by an operator after proper staining. The determination of the positivity threshold may vary depending on the operator. We developed a new method in which the final step of determining cell viability is automated using the NC-3000™ (Chemometec®), an image cytometer able to precisely determine the percentage of dead/live cells in a suspension. After T and B donor cells isolation by negative selection, complement-dependent lysis was performed in macrovolumes in a PCR plate. Then, cell viability was measured by the NC-3000™. The sensitivity and routine CDC-XM results of this new method were compared to those of CDC-XM reference method using Terasaki plates. The sensitivity of CDC-XM expressed in the ASHI scoring system of this method was similar to the reference method results for a dilution range of the positive controls. Similarly, the results of the new method were comparable in a clinical situation to those obtained with the reference method after a study of 10 cross-matches, of which 5 cross-matches with DSA were positive and five cross-matches without DSA were negative. Moreover, ASHI scores were similar to those obtained using the reference method, and the mortality percentage was reproducible (CV < 15%). The assessment of cell viability by the NC-3000™ is easy to perform and highly reproducible but requires CDC-XM to be performed by the macrovolume method. The determination of a precise percentage of viability/mortality by the automation excludes operator variability and allows a better understanding of results close to the decision threshold.

Detection of taste thresholds at different growth stages of broilers

The sense of taste has a key role in nutrient sensing and food intake in poultry. A standardized and simple method for the determination of tastant-detection thresholds is required for chemosensory research in poultry as well poultry feed formulation. The goal of the study was to evaluate the effect of aging on the behavioural taste sensitivities of broiler chickens in order to improve the efficiency of feeding through correct feed selection and ration preparation. It especially aimed to establish the threshold concentrations of five different taste components (sweet, sour, bitter, salt, and umami). Total of 15 feeding trials for broiler chicks of various ages were performed. For each taste quality, the powdered flavor active ingredients for sweet, sour, bitter, salty, and umami were selected. The actual drinking volume of water and taste solution was identified. Because the p values were less than 0.05, the concentrations of sucrose (100 mM), citric acid (50 mM), sodium chloride (20 mM), caffeine (10 mM), and mono-sodium glutamate (MSG) (100 mM) were significant. Taken together, it may be concluded that the taste active chemical sensitivity was very "concentration-dependent" manner for the aforementioned concentrations and that younger chickens have a greater sense of taste than older birds. Bangladesh Journal of Animal Science 52 (1): 22-28, March 2023

Advances and perspectives on the research of starfish outbreaks in northern China.

In recent years, starfish outbreaks occurred frequently in northern China, causing serious economic losses to marine aquaculture. The most common outbreak starfish species are Asterias amurensis and Asterina pectini-fera. We systematically reviewed the related studies by introducing the biological characteristics, current outbreaking status, and main impact of A. amurensis and A. pectinifera, and by discussing the causes, formation process, and migration pattern of starfish outbreaks in northern China. The early life history stage drives starfish outbreak. The increases of larval survival rate is the key leading to population outbreak. Population connectivity is the vital clue to reveal the source and dispersal of starfish populations. On this basis, we proposed several scientific and technical issues that should be addressed urgently, including the determination of the outbreak threshold, the traceability of starfish population, and the methods of monitoring, early warning and control. It would provide insight into the research on the mechanism of starfish outbreaks and the theoretical support for formulating prevention and treatment strategies for starfish outbreaks in northern China.

Amoxicillin-Induced Neurotoxicity: Contribution of a Healthcare Data Warehouse to the Determination of a Toxic Concentration Threshold.

Amoxicillin (AMX)-induced neurotoxicity is well described and may be associated with AMX overexposure. No neurotoxic concentration threshold has been determined thus far. A better knowledge of maximum tolerable AMX concentrations is of importance to improve the safety of high doses of AMX. We conducted a retrospective study using the local hospital data warehouse EhOP® to generate a specific query related to AMX neurotoxicity symptomatology. All patient medical reports containing a mention of neurotoxicity clinical symptoms coupled with AMX plasma concentration measurements were explored. Patients were classified into two groups according to the imputability of AMX in the onset of their neurotoxicity, on the basis of chronological and semiological criteria. A receiver-operating characteristic curve was performed to identify an AMX neurotoxic steady-state concentration (Css) threshold. The query identified 101 patients among 2054 patients benefiting from AMX TDM. Patients received a median daily dose of 9 g AMX, with a median creatinine clearance of 51 mL/min. A total of 17 of the 101 patients exhibited neurotoxicity attributed to AMX. The mean Css was higher for patients with neurotoxicity attributed to AMX (118 ± 62 mg/L) than those without 74 ± 48 mg/L (p = 0.002). A threshold AMX concentration of 109.7 mg/L predicted the occurrence of neurotoxicity. This study identified, for the first time, an AMX Css threshold of 109.7 mg/L associated with an excess risk of neurotoxicity. This approach needs to be confirmed by a prospective study with systematic neurological evaluation and TDM.

Extracting vegetation information from high dynamic range images with shadows: A comparison between deep learning and threshold methods

Due to factors such as light angle and vegetation density, shadows can exist in ground vegetation images; this can lead to highly varying natural illumination in the images, which greatly limits the accuracy of fractional vegetation cover (FVC) estimation. While high dynamic range (HDR) images can reduce the extreme illumination contrast, the characteristic vegetation information in shadow areas is often lost. At present, most threshold methods do not fully utilize the spatial features of vegetation, and the results of vegetation classification under complex shadow conditions are associated with large errors. Thus, two deep learning methods (the HDR U-Net method and HDR U-Net++ method) are proposed in this study based on fully convolutional neural networks to extract vegetation information from HDR images under shadow conditions. These methods are compared with threshold methods. For full HDR images, the kappa coefficient and mean intersection over union (MIoU) of the HDR U-Net method and HDR U-Net++ method are 0.926, 0.931, and 0.874, 0.887, respectively. The FVC estimation accuracy and vegetation segmentation effect of these two deep learning methods are better than those of the three threshold methods considered. In addition, compared with normal exposure (NE) images, camera-based HDR images improve the extraction accuracy of deep learning methods and threshold methods for vegetation under shadow conditions. The results of this study suggest that deep learning methods are not affected by the threshold determination strategy selected and can more completely extract vegetation feature information from HDR images. The classification effect of vegetation under shadow conditions is effectively improved, and the vegetation segmentation and FVC estimation results are more precise. The combination of HDR images and deep learning methods can be applied to field scenes with complex lighting, which is beneficial to improve the ground data verification of remote sensing FVC products.

Fault diagnosis of complex hydraulic system based on fast Mahalanobis classification system with high-dimensional imbalanced data

Due to the complexity of hydraulic systems, the data generated is prone to be high-dimensional and imbalanced, posing a challenge for fault diagnosis. This paper proposes a fast Mahalanobis classification system (FMCS). At the dimensionality reduction stage, smymetrical uncertainty and Mahalanobis kernel principal component analysis are used to construct a two-stage fast dimensionality reduction method. At the weight distribution stage, Mahalanobis distance is used to measure the similarity between the main feature and other features to determine the feature weights. At the fault diagnosis stage, Mahalanobis-Taguchi system is improved in threshold determination by atom search optimization to achieve fault diagnosis. Experiments show that FMCS has better classification performance (accuracy = 0.92, F1 = 0.94, G-mean = 0.91) and shorter computing time (4.9045 s) compared with 24 baseline algorithms. FMCS promotes the development of intelligent fault diagnosis for complex hydraulic systems.