Kliknij ten link, aby zobaczyć inne rodzaje publikacji na ten temat: Evaluation Coupling Graph (ECG).
Artykuły w czasopismach na temat „Evaluation Coupling Graph (ECG)”
Utwórz poprawne odniesienie w stylach APA, MLA, Chicago, Harvard i wielu innych
Sprawdź 25 najlepszych artykułów w czasopismach naukowych na temat „Evaluation Coupling Graph (ECG)”.
Przycisk „Dodaj do bibliografii” jest dostępny obok każdej pracy w bibliografii. Użyj go – a my automatycznie utworzymy odniesienie bibliograficzne do wybranej pracy w stylu cytowania, którego potrzebujesz: APA, MLA, Harvard, Chicago, Vancouver itp.
Możesz również pobrać pełny tekst publikacji naukowej w formacie „.pdf” i przeczytać adnotację do pracy online, jeśli odpowiednie parametry są dostępne w metadanych.
Przeglądaj artykuły w czasopismach z różnych dziedzin i twórz odpowiednie bibliografie.
1
Zhao, Zhiyao, Xuanhao Li, Xiaoyu Cui i Xin Zhang. "Fault Coupling Analysis and Reliability Assessment of Actuation System Based on Bond Graph Model". Applied Sciences 13, nr 13 (24.06.2023): 7462. http://dx.doi.org/10.3390/app13137462.
Pełny tekst źródłaStreszczenie:
In this paper, a new degradation model of the more electrical aircraft (MEA) actuation system is proposed. The bond graph model is used to build the dissimilar redundancy actuation system model, taking into account the degradation behavior (wear, fatigue, aging) of components in the system operation and the fault coupling phenomenon caused by the accumulation of dissipated energy in space and time, and a fault coupling degradation model of the actuation system is established with clear mechanism support. Through the fault mechanism analysis, various fault types are injected into the bond graph model of the actuation system, and the simulation results are compared. The influence of fault propagation on system output is analyzed, the system’s reliability is assessed, and the performance evaluation of the actuation system is realized while taking the fault coupling mechanism into account.
2
Liu, Lihua, Jing Huang i Huimin Wang. "Visibility Graph Power Geometric Aggregation Operator and Its Application in Water, Energy and Food Efficiency Evaluation". International Journal of Environmental Research and Public Health 17, nr 11 (30.05.2020): 3891. http://dx.doi.org/10.3390/ijerph17113891.
Pełny tekst źródłaStreszczenie:
In the real decision-making process, there are so many time series values that need to be aggregated. In this paper, a visibility graph power geometric (VGPG) aggregation operator is developed, which is based on the complex network and power geometric operator. Time series data are converted into a visibility graph. A visibility matrix is developed to denote the links among different time series values. A new support function based on the distance of two values are proposed to measure the support degree of each other when the two time series values have visibility. The VGPG operator considers not only the relationship but also the similarity degree between two values. Meanwhile, some properties of the VGPG operator are also investigated. Finally, a case study for water, energy, and food coupling efficiency evaluation in China is illustrated to show the effectiveness of the proposed operator. Comparative analysis with the existing research is also offered to show the advantages of the proposed method.
3
Perpetuini, David, Antonio Maria Chiarelli, Lidia Maddiona, Sergio Rinella, Francesco Bianco, Valentina Bucciarelli, Sabina Gallina i in. "Multi-Site Photoplethysmographic and Electrocardiographic System for Arterial Stiffness and Cardiovascular Status Assessment". Sensors 19, nr 24 (17.12.2019): 5570. http://dx.doi.org/10.3390/s19245570.
Pełny tekst źródłaStreszczenie:
The development and validation of a system for multi-site photoplethysmography (PPG) and electrocardiography (ECG) is presented. The system could acquire signals from 8 PPG probes and 10 ECG leads. Each PPG probe was constituted of a light-emitting diode (LED) source at a wavelength of 940 nm and a silicon photomultiplier (SiPM) detector, located in a back-reflection recording configuration. In order to ensure proper optode-to-skin coupling, the probe was equipped with insufflating cuffs. The high number of PPG probes allowed us to simultaneously acquire signals from multiple body locations. The ECG provided a reference for single-pulse PPG evaluation and averaging, allowing the extraction of indices of cardiovascular status with a high signal-to-noise ratio. Firstly, the system was characterized on optical phantoms. Furthermore, in vivo validation was performed by estimating the brachial-ankle pulse wave velocity (baPWV), a metric associated with cardiovascular status. The validation was performed on healthy volunteers to assess the baPWV intra- and extra-operator repeatability and its association with age. Finally, the baPWV, evaluated via the developed instrumentation, was compared to that estimated with a commercial system used in clinical practice (Enverdis Vascular Explorer). The validation demonstrated the system’s reliability and its effectiveness in assessing the cardiovascular status in arterial ageing.
4
Hua, Xian, Jing Li, Ting Wang, Junhong Wang, Shaojun Pi, Hangcheng Li i Xugang Xi. "Evaluation of movement functional rehabilitation after stroke: A study via graph theory and corticomuscular coupling as potential biomarker". Mathematical Biosciences and Engineering 20, nr 6 (2023): 10530–51. http://dx.doi.org/10.3934/mbe.2023465.
Pełny tekst źródłaStreszczenie:
<abstract> <p>Changes in the functional connections between the cerebral cortex and muscles can evaluate motor function in stroke rehabilitation. To quantify changes in functional connections between the cerebral cortex and muscles, we combined corticomuscular coupling and graph theory to propose dynamic time warped (DTW) distances for electroencephalogram (EEG) and electromyography (EMG) signals as well as two new symmetry metrics. EEG and EMG data from 18 stroke patients and 16 healthy individuals, as well as Brunnstrom scores from stroke patients, were recorded in this paper. First, calculate DTW-EEG, DTW-EMG, BNDSI and CMCSI. Then, the random forest algorithm was used to calculate the feature importance of these biological indicators. Finally, based on the results of feature importance, different features were combined and validated for classification. The results showed that the feature importance was from high to low as CMCSI/BNDSI/DTW-EEG/DTW-EMG, while the feature combination with the highest accuracy was CMCSI+BNDSI+DTW-EEG. Compared to previous studies, combining the CMCSI+BNDSI+DTW-EEG features of EEG and EMG achieved better results in the prediction of motor function rehabilitation at different levels of stroke. Our work implies that the establishment of a symmetry index based on graph theory and cortical muscle coupling has great potential in predicting stroke recovery and promises to have an impact on clinical research applications.</p> </abstract>
5
Berselli, Giovanni, Rocco Vertechy, Mitja Babič i Vincenzo Parenti Castelli. "Dynamic modeling and experimental evaluation of a constant-force dielectric elastomer actuator". Journal of Intelligent Material Systems and Structures 24, nr 6 (28.08.2012): 779–91. http://dx.doi.org/10.1177/1045389x12457251.
Pełny tekst źródłaStreszczenie:
Constant-force actuators based on dielectric elastomers can be obtained by coupling a dielectric elastomer film with particular compliant frames whose structural properties must be carefully designed. In any case, the practical achievement of a desired force profile can be quite a challenging task owing to the time-dependent phenomena, which affect the dielectric elastomer’s electromechanical response. Within this scenario, a hyperviscoelastic model of a rectangular constant-force actuator is reported. The model, based on the bond graph formalism, can be used as an engineering tool when designing and/or controlling actuators that are expected to work under given nominal conditions. Simulations and experimental results are provided, which predict the system response to fast changes in activation voltage and actuator position as imposed by an external user.
6
Orlova, Е. А., О. S. Tarasova, V. D. Son'kin i А. S. Borovik. "INFLUENCE OF THE AGE ON BAROREFLEX SYNCHRONIZATION OF ARTERIAL PRESSURE AND HEART RATE DURING THE PASSIVE STANDING TEST". Aerospace and Environmental Medicine 55, nr 1 (2021): 46–50. http://dx.doi.org/10.21687/0233-528x-2021-55-1-46-50.
Pełny tekst źródłaStreszczenie:
Age-related changes in phase synchronization of spontaneous blood pressure (BP) and heart rate (HR) fluctuations within the baroreflex wave range (about 0.1 Hz) were studied in 66 subjects aged 20 to 52 years. Measurements performed during the head-up tilt test included continuous BP monitoring using the volume-compensation method, ECG recording for ensuing HR calculation, and breathing rate recording. The phase synchronization index (PSI) was used for evaluation of BP-HR coupling. In supine position, phase synchronization in the subjects over 40 years was higher as compared with their counterparts at the age of 20 to 24 years. Along with that, less pronounced PSI increase in people over 40 in response to the tilt test suggests a decline of the baroreflex activity with aging.
7
Huang, Shanshan. "Research hotspots and knowledge graph analysis of the relationship between Urbanization and Ecological Environment in the Yellow River Basin". SHS Web of Conferences 157 (2023): 03007. http://dx.doi.org/10.1051/shsconf/202315703007.
Pełny tekst źródłaStreszczenie:
Based on the literature sample data of the research topics related to urbanization and ecological environment relationship in the Yellow River Basin in CNKI database from 2000 to 2022, this paper uses excle and CiteSpace software to systematically sort out the preface, current hot spots and development trends of the research on the relationship between urbanization and ecological environment in the Yellow River Basin through volume analysis, keyword co-occurrence and cluster analysis, and the results show that the existing research scale tends to be smaller, and pays attention to multi-scale analysis and comparison. Comparing research from a large to a small scale is easier to solve practical problems; Secondly, it shows the cross-combination of measurement methods, and some studies pay attention to the cross-combination of mathematical models and spatial measurement methods in coupling measurement methods. Finally, the research content shifted from qualitative status analysis and static evaluation to quantitative analysis and dynamic trend evaluation.
8
Nakayama, Fernando, Paulo Lenz, Stella Banou, Michele Nogueira, Aldri Santos i Kaushik R. Chowdhury. "A Continuous User Authentication System Based on Galvanic Coupling Communication for s-Health". Wireless Communications and Mobile Computing 2019 (28.11.2019): 1–11. http://dx.doi.org/10.1155/2019/9361017.
Pełny tekst źródłaStreszczenie:
Smart health (s-health) is a vital topic and an essential research field today, supporting the real-time monitoring of user’s data by using sensors, either in direct or indirect contact with the human body. Real-time monitoring promotes changes in healthcare from a reactive to a proactive paradigm, contributing to early detection, prevention, and long-term management of health conditions. Under these new conditions, continuous user authentication plays a key role in protecting data and access control, once it focuses on keeping track of a user’s identity throughout the system operation. Traditional user authentication systems cannot fulfill the security requirements of s-health, because they are limited, prone to security breaches, and require the user to frequently authenticate by, e.g., a password or fingerprint. This interrupts the normal use of the system, being highly inconvenient and not user friendly. Also, data transmission in current authentication systems relies on wireless technologies, which are susceptible to eavesdropping during the pairing stage. Biological signals, e.g., electrocardiogram (ECG) and electroencephalogram (EEG), can offer continuous and seamless authentication bolstered by exclusive characteristics from each individual. However, it is necessary to redesign current authentication systems to encompass biometric traits and new communication technologies that can jointly protect data and provide continuous authentication. Hence, this article presents a novel biosignal authentication system, in which the photoplethysmogram (PPG) biosignal and a galvanic coupling (GC) channel lead to continuous, seamless, and secure user authentication. Furthermore, this article contributes to a clear organization of the state of the art on biosignal-based continuous user authentication systems, assisting research studies in this field. The evaluation of the system feasibility presents accuracy in keeping data integrity and up to 98.66% accuracy in the authentication process.
9
Shi, Tongtong, Ping Wang, Xudong Qi, Jiacheng Yang, Rui He, Jingwen Yang i Yu Han. "CPT-DF: Congestion Prediction on Toll-Gates Using Deep Learning and Fuzzy Evaluation for Freeway Network in China". Journal of Advanced Transportation 2023 (10.04.2023): 1–16. http://dx.doi.org/10.1155/2023/2941035.
Pełny tekst źródłaStreszczenie:
Toll-gates are crucial points of management and key congestion bottleneck for the freeway. In order to avoid traffic deterioration and alleviate traffic congestion in advance, it is necessary to predict and evaluate the congestion in toll-gates scattering in large-scale region of freeway network. In this paper, traffic volume and operational delay time are selected from various traffic indicators to evaluate congestion considering the particular characteristics of the traffic flow within the toll-gate area. The congestion prediction method is designed including two modules: a deep learning (DL) prediction and a fuzzy evaluation. We propose a modified deep learning method based on graph convolutional network (GCN) structure in the fusion of dilated causal mechanism and optimize the method for spatial feature extraction by constructing a new adjacency matrix. This new AI network could process spatiotemporal information of traffic volume and operational delay time, that extracted from large-scaled toll-gates spontaneously, and predict key indicators in 15/30/60 min future time. The evaluation module is proposed based on these predicted results. Then, fuzzy C-means algorithm (FCM) is further modified by determining coupling weight for these two key indicators to detect congestion state. Original traffic data are obtained from the current 186 toll-gates served on the freeway network in Shaanxi Province, China. Experimental tests are carried out based on historical data of four months after preprogressing. The comparative tests show the proposed CPT-DF (congestion prediction on toll-gates using deep learning and fuzzy evaluation) outperforms the current-used other models by 6-15%. The successful prediction could extend to the real-time prediction and early warning of traffic congestion in the toll system to improve the intelligent level of traffic emergency management and guidance on the key road of disasters to some extent.
10
Li, He, Quan Liu, Xiaopu Ma, Qinglei Qi, Jinjiang Liu, Pan Zhao, Yang Yang i Xingang Zhang. "Cooperative Recharge Scheme Based on a Hamiltonian Path in Mobile Wireless Rechargeable Sensor Networks". Mathematical Problems in Engineering 2022 (19.05.2022): 1–20. http://dx.doi.org/10.1155/2022/6955713.
Pełny tekst źródłaStreszczenie:
The energy problem and limited capacity of batteries have been fundamental constraints in many wireless sensor network (WSN) applications. For WSN, the wireless energy transmission technology based on magnetic resonance coupling is a promising energy transmission technology. To reduce the cost and energy consumption during charging in mobile wireless rechargeable sensor networks (MWRSNs), a cooperative mobile charging mechanism based on the Hamiltonian path is proposed in this paper. To improve the charging task interval, we study the use of a mobile charger (MC) as a mobile sink node to collect the data in this paper. Then, we used the sink and the charging sensors selected by the MC to construct the undirected complete graph. Finally, the Euclidean distance between nodes is used as the edge weight and a Hamiltonian loop is found by using the improved Clark–Wright (C-W) saving algorithm to solve the problem of charging a rechargeable sensor network. In addition to the energy usage efficiency (EUE) and the network lifetime, the average energy loss per unit time is considered as the evaluation index according to the impact of the MC on the energy consumption during charging. The simulation results show that the proposed scheme increases the average network lifetime, decreases the average energy loss per unit time, and improves the EUE.
11
Izzat Bin Zainuddin, Mohd, i CV Aravind. "Design Analysis of a Dual Rotor Permanent Magnet Machine driven Electric Vehicle". MATEC Web of Conferences 152 (2018): 03004. http://dx.doi.org/10.1051/matecconf/201815203004.
Pełny tekst źródłaStreszczenie:
Electric bike in urban countries such as Europe and China commonly used the brushless direct current machine (BLDC) as it able to produce high torque to transport the user from one place to another. However, BLDC torque density can’t be improving due to limitation magnetic flux generated by the permanent magnet. Therefore, the performance of electric bike can’t be improved. Outer rotor BLDC machine design able to improve the torque density of the motor due to increase radius of the motor which can be explained by simple physics equation (Torque = Force x radius). However, an outer rotor machine only generates constant speed, which is not suitable for operating under tractive load condition, especially electric bike. The proposed model is a new novel of double layer outer rotor BLDCPM machine which able to amplify the magnetic flux density and improve the torque density of the machine. The mutual magnetic coupling between the inner and outer rotor of the proposed model increase the magnetic flux intensity as both of them acts as individual parts. Thus, the magnetic flux generated by both rotors are double which resulted in improving the performance of the E-bike. Designing parameters and analysing the performance of the proposed 2D model is done using FEA tools. Evaluation of the conventional and proposed model by comparing torque performance, magnetic flux density and motor constant square density. Other than that, speed torque graph also is evaluated to justify either it can operate similarly to ICE engine with gears. Two model is designed which is Single Outer Rotor Brushless Direct Current (SORBLDC) and Double Outer Rotor Brushless Direct Current (DORBLDC) operated with the same cases of 27 Amp current supplied to it and operate under various speed from 500 rpm to 2000 rpm. The average torque produce by the conventional and proposed model are 2.045439 Nm and 3.102648 Nm. Furthermore, improvement of the proposed model to conventional model in terms of motor constant square density by 24.92%. Therefore, the proposed model able to improve the magnetic flux by amplifying which resulted to increase the torque density of the machine. Furthermore, the speed-torque graph of the proposed machine shows similarity with speed torque graph of ICE engine. Thus, the proposed machine is suitable to operate for bike application
12
Chen, Wenxing, Shuyang Dai i Baojuan Zheng. "Thermal-Mechanical Coupling Model Based on the Hybrid Finite Element Method for Solving Bipolar the Plate Deformation of Hydrogen Fuel Cells". Machines 10, nr 7 (23.06.2022): 505. http://dx.doi.org/10.3390/machines10070505.
Pełny tekst źródłaStreszczenie:
New energy is the focus of attention all over the world, and research into new energy can inject new vitality into the industrial system. Hydrogen fuel cells are not only environmentally friendly, but also rich in reserves that can be used as a strategic resource for the entire country. The difficulty lies in the safe design of application equipment and the batch generation and storage of hydrogen. In addition, fuel cells have the disadvantage of a slow start-up. Based on the above problems, this paper proposes a hybrid-element method to solve the thermal-mechanical coupling model of fuel cell plate, which can effectively solve the thermal stress change, temperature field distribution and displacement change of the battery plate when working. Firstly, the hybrid-element algorithm is given for 2D plate deformation. Then, the deformation application of a 3D fuel cell plate is given. The 2D numerical results show that the hybrid finite element method (FEM) is more flexible for realizing the flexible combination of sub-mesh and finite element basis functions, and has a better mesh quality compared to the traditional constant strain triangular element (CST) adaptive FEM and quadrilateral isoparametric element (Q4) adaptive FEM. This method achieves a balance between numerical accuracy and solving efficiency for the multi-porous elastic plate. In addition, a deformation control formula is given which can display the displacement deformation and stress merge to same graph, since it is convenient to quickly compare the regions where the displacement and stress extremum appear. In short, the hybrid finite element method proposed in this paper has good mesh evaluation results, and when the number of discrete elements is equivalent, the hybrid element converges faster and the solution efficiency is higher. This paper also provides a good numerical theory and simulation reference for industrial mechanics and new energy applications.
13
Zhu, Zhaowei, Jingxuan Zhu, Ji Liu i Yang Liu. "Federated Bandit". Proceedings of the ACM on Measurement and Analysis of Computing Systems 5, nr 1 (18.02.2021): 1–29. http://dx.doi.org/10.1145/3447380.
Pełny tekst źródłaStreszczenie:
In this paper, we study Federated Bandit, a decentralized Multi-Armed Bandit problem with a set of N agents, who can only communicate their local data with neighbors described by a connected graph G. Each agent makes a sequence of decisions on selecting an arm from M candidates, yet they only have access to local and potentially biased feedback/evaluation of the true reward for each action taken. Learning only locally will lead agents to sub-optimal actions while converging to a no-regret strategy requires a collection of distributed data. Motivated by the proposal of federated learning, we aim for a solution with which agents will never share their local observations with a central entity, and will be allowed to only share a private copy of his/her own information with their neighbors. We first propose a decentralized bandit algorithm \textttGossip\_UCB, which is a coupling of variants of both the classical gossiping algorithm and the celebrated Upper Confidence Bound (UCB) bandit algorithm. We show that \textttGossip\_UCB successfully adapts local bandit learning into a global gossiping process for sharing information among connected agents, and achieves guaranteed regret at the order of O(\max\ \textttpoly (N,M) łog T, \textttpoly (N,M)łog_łambda_2^-1 N\ ) for all N agents, where łambda_2\in(0,1) is the second largest eigenvalue of the expected gossip matrix, which is a function of G. We then propose \textttFed\_UCB, a differentially private version of \textttGossip\_UCB, in which the agents preserve ε-differential privacy of their local data while achieving O(\max \\frac\textttpoly (N,M) ε łog^2.5 T, \textttpoly (N,M) (łog_łambda_2^-1 N + łog T) \ ) regret.
14
Zhu, Zhaowei, Jingxuan Zhu, Ji Liu i Yang Liu. "Federated Bandit: A Gossiping Approach". ACM SIGMETRICS Performance Evaluation Review 49, nr 1 (22.06.2022): 3–4. http://dx.doi.org/10.1145/3543516.3453919.
Pełny tekst źródłaStreszczenie:
We study Federated Bandit, a decentralized Multi-Armed Bandit (MAB) problem with a set of N agents, who can only communicate their local data with neighbors described by a connected graph G. Each agent makes a sequence of decisions on selecting an arm from M candidates, yet they only have access to local and potentially biased feedback/evaluation of the true reward for each action taken. Learning only locally will lead agents to sub-optimal actions while converging to a no-regret strategy requires a collection of distributed data. Motivated by the proposal of federated learning, we aim for a solution with which agents will never share their local observations with a central entity, and will be allowed to only share a private copy of his/her own information with their neighbors. We first propose a decentralized bandit algorithm GossipUCB, which is a coupling of variants of both the classical gossiping algorithm and the celebrated Upper Confidence Bound (UCB) bandit algorithm. We show that GossipUCB successfully adapts local bandit learning into a global gossiping process for sharing information among connected agents, and achieves guaranteed regret at the order of O(max(poly(N,M) log T, poly(N,M) logλ2-1 N)) for all N agents, where λ2∈(0,1) is the second largest eigenvalue of the expected gossip matrix, which is a function of G. We then propose FedUCB, a differentially private version of GossipUCB, in which the agents preserve ε-differential privacy of their local data while achieving O(max poly(N,M)/ε log2.5 T, poly(N,M) (logλ2-1 N + log T)) regret.
15
Nikita Landge, Ajaz Khan, Aasir Awez, Khan M Tarkhan i Prof. Khwaja Ramizuddin. "ECG Graph Monitoring System using Ad8232 with ECG Sensor and Arduino". International Journal of Advanced Research in Science, Communication and Technology, 21.05.2022, 319–20. http://dx.doi.org/10.48175/ijarsct-3927.
Pełny tekst źródłaStreszczenie:
Patient monitoring is the heart of the fitness care domain in day to day lifestyles both at domestic or at medical institution. This paper affords the layout of a transportable electrocardiograph (ECG) device the use of the AD8232 microchip as the analog front-stop (AFE). Beginning with the producer’s evaluation board of the AFE chip for testing circuit configurations, open-supply hardware and software components had been integrated into a breadboard prototype. In the long run, a custom printed circuit board (PCB) changed into produced. The prototype required to accommodate the microchip on a SMD-to-DIP adapter for checking out with the breadboard-pleasant Arduino microcontroller alongside a statistics logger and a Bluetooth breakout board. The analog ECG sign from the AFE output changed into digitized the use of one channel of the 10-bit analog-to-virtual Converter (ADC) of the ATmega328 microcontroller contained in the Arduino Nano board. The digitized ECG signal may be transmitted not simplest with the aid of serial cable using the Arduino capabilities, but also thru Bluetooth to a computer or to an Android telephone gadget whilst the HC-06 guard is used. The records logging guard presents gigabytes of garage, and the sign is recorded to a micro SD card adapter in conjunction with the date and time stamp information of the pattern seize (actual-time clock provided). further to hardware and software improvement, a simulation was used in the analog circuit design with SPICE Multisim software program and the related macro model library to assess machine stability. besides the analog filters within the AFE degree, virtual filtering through easy distinction equations become investigated. A menu turned into incorporated to pick out from the several modes of operation of the device. The ECG test signals were acquired from a affected person simulator (SimCube) and real sufferers. A portable ECG gadget for tracking applications that complies with electric protection regulations and medical equipment design became found out.
16
Hadiyoso, Sugondo, Suci Aulia i Indrarini Dyah Irawati. "Multi-Class Heart Abnormalities Detection Based on ECG Graph Using Transfer Learning Method". Jurnal Rekayasa Elektrika 19, nr 1 (27.03.2023). http://dx.doi.org/10.17529/jre.v19i1.28637.
Pełny tekst źródłaStreszczenie:
The heart is one of the vital organs in the circulatory system. Regular checkups are very important to prevent heart disease. The most basic examination is blood pressure then further examination is related to the evaluation of the electrical activity of the heart using an electrocardiogram (ECG). The ECG carries important information regarding various abnormalities of heart function. Several automated classification techniques have been proposed to facilitate diagnosis. However, not all digital ECG devices provide raw data for analysis. ECG classification method based on images can be an alternative in classification. Therefore, in this study, it is proposed to classify ECG based on signal images. The proposed classification method uses transfer learning with VGG, AlexNet, and DenseNet architectures. The method used for the classification of multi-class ECG consists of normal, PVC, Atrial Fibrilation, AFL, Bigeminy, LBBB, and APB. The simulation results generate the best accuracy of 92% and F1-score of 92%. Best performance is achieved using DenseNet architecture at 60 epochs. This study is expected to be a new reference technique in the classification of ECG signals.
17
Costa, J., L. Bichon, A. Maouche, P. Durdon, R. Pouy i A. Robbins. "Evaluation of Perugini score and myocardial mass and voltage abnormalities in transthyretine cardiac amyloidosis". European Heart Journal 42, Supplement_1 (1.10.2021). http://dx.doi.org/10.1093/eurheartj/ehab724.1807.
Pełny tekst źródłaStreszczenie:
Abstract Background Transthyretine cardiac amyloidosis (TTR-CA) is an emerging treatable disease in cardiology. Severity of TTR infiltration can be assessed by bone scintigraphy with Perugini score, depending on HPD-Tc99M myocardial intensity uptake. Less is known on how Perugini score interplays with routine cardiac structural parameters, especially cardiac mass and voltage. Aim To evaluate correlation between Perugini score and myocardial mass and voltage abnormalities in patients with TTR-CA. Methods Patients diagnosed with ATTR-CA and addressed to our center for treatment underwent complete evaluation including electrocardiogram (ECG) and transthoracic echocardiography (TTE). Routine electrical and echographic parameters were obtained such as: Sokolow indice (SV1+RV5) in millivolt (mV), PR delay (ms), QRS width (in ms), left ventricular mass (LVM, in grams) and diastolic interventricular septum (dIVS) thickness (in mm). Patients were classified in three categories according to Perugini score: I (cardiac uptake < chest bones), II (cardiac uptake = chest bones) and III (cardiac uptake > bones). Main end-point were LVM and Voltage/Mass ratio (VMR) variations, depending on Perugini score. Results Among the 17 patients included, 14 were male (82.4%) and mean age was 82±8 years old. On ECG, 6 patients (35.3%) had permanent atrial fibrillation (AF). Mean voltage according to Sokolow index, mean PR delay and mean QRS width were respectively 1.5±0.5 mV, 212±54 ms and 113±19 ms. On TTE, mean LVM and mean dIVS width were respectively 333±98 g (188±55 g/m2) and 19±4 mm. Mean voltage/mass ratio (VMR) was 0.48±0.26 uV/g (see table). On bone scintigraphy, 3 patients were scored with Perugini I (17.6%), 4 with Perugini II (23.5%) and 10 with Perugini III (58.8%). According to Pearson test, there was a strong correlation between Perrugini score and LVM (r=+0.56, p=0.03) (graph A), and a strong negative correlation between Perrugini score and VMR (r=−0.70, p=0.003) (graph B). There were a trend for correlation between Perugini score and Voltage according to Sokolow (r=−0.46, p=0.07) and between Perugini score and dIVS width (r=0.49, p=0.07). Conclusion In TTR-CA patients, Perugini score appears to strongly correlate with left ventricle mass and voltage. Larger scale studies are needed to confirm these results. Funding Acknowledgement Type of funding sources: None. ECG and TEE trends according to PeruginiCardiac mass and voltage with Perugini
18
Alkhodari, Mohanad, Namareq Widatalla, Maisam Wahbah, Raghad Al Sakaji, Kiyoe Funamoto, Anita Krishnan, Yoshitaka Kimura i Ahsan H. Khandoker. "Deep learning identifies cardiac coupling between mother and fetus during gestation". Frontiers in Cardiovascular Medicine 9 (29.07.2022). http://dx.doi.org/10.3389/fcvm.2022.926965.
Pełny tekst źródłaStreszczenie:
In the last two decades, stillbirth has caused around 2 million fetal deaths worldwide. Although current ultrasound tools are reliably used for the assessment of fetal growth during pregnancy, it still raises safety issues on the fetus, requires skilled providers, and has economic concerns in less developed countries. Here, we propose deep coherence, a novel artificial intelligence (AI) approach that relies on 1 min non-invasive electrocardiography (ECG) to explain the association between maternal and fetal heartbeats during pregnancy. We validated the performance of this approach using a trained deep learning tool on a total of 941 one minute maternal-fetal R-peaks segments collected from 172 pregnant women (20–40 weeks). The high accuracy achieved by the tool (90%) in identifying coupling scenarios demonstrated the potential of using AI as a monitoring tool for frequent evaluation of fetal development. The interpretability of deep learning was significant in explaining synchronization mechanisms between the maternal and fetal heartbeats. This study could potentially pave the way toward the integration of automated deep learning tools in clinical practice to provide timely and continuous fetal monitoring while reducing triage, side-effects, and costs associated with current clinical devices.
19
Hoeksema, W. F., M. H. Van Der Ree, E. M. T. Dieleman, J. Visser, R. N. Planken, R. H. A. De Bruin-Bon, R. M. A. J. De Jong i in. "Stereotactic arrhythmia radiotherapy for ventricular tachycardia does not appear to alter QRS duration and QTc interval: a secondary analysis of the prospective STARNL-1 trial". Europace 25, Supplement_1 (24.05.2023). http://dx.doi.org/10.1093/europace/euad122.337.
Pełny tekst źródłaStreszczenie:
Abstract Funding Acknowledgements Type of funding sources: Foundation. Main funding source(s): Dutch Heart Foundation grant to dr. P.G. Postema, MD PhD Background Stereotactic arrhythmia radiotherapy (STAR) has evolved as promising bail-out treatment in patients with therapy-refractory ventricular tachycardia (VT). The mechanism of action of STAR in preventing VT has yet to be elucidated and further understanding could improve this technique in the future. Preclinical studies reported an increase in conduction velocity and consequently a decrease in conduction intervals on electrocardiograms (ECGs) within the first months after STAR, although this has not yet been evaluated in detail in prospective studies. Purpose To evaluate the early effects of STAR on ventricular conduction as electrocardiographically assessed. Methods The STARNL-1 was a prospective, monocenter, pre-post intervention study. Six patients with VT recurrences despite optimal doses of anti-arrhythmic drugs (AADs), after one or more unsuccessful catheter ablation(s), were considered therapy-refractory. Patients were treated with a single fraction of 25 Gy. ECG evaluation included ECGs recorded pre-therapy, at 3 hours, 12 hours, 24 hours, 1 month, and 3 months after therapy. For an additional assessment, only patients in whom AADs remained unchanged up to 3 months after STAR were selected. QRS duration and QT interval were measured by a single observer using digital callipers. Four consecutive beats were used to measure and calculate a mean QRS duration and QT interval per ECG. This study was not powered to evaluate for significant changes in ECG parameters. Results All patients were male, all suffered from ischaemic cardiomyopathy, and all completed 3-month follow-up. One patient presented with atrial fibrillation on ECG recordings, and three patients with a paced rhythm. Four patients (66.7%) were selected for an additional assessment, two patients (P1 and P2, 33.3%) underwent changes in AAD dose and were therefore excluded. Figure 1 shows a line graph of the QRS duration and QTc interval of all STARNL-1 patients during 3-month follow-up. As can be appreciated from Figure 1, QRS duration and QTc interval did not appear to be altered between pre-therapy and 3 months after therapy. When excluding P1 and P2, QRS duration and QTc interval also did not appear to be altered between pre-therapy and 3 months after therapy. Conclusion(s) STAR for VT does not appear to alter QRS duration and QTc interval within the first 3 months after therapy.
20
Wu, Zhaohong, Matthew I. Campbell i Benito R. Fernández. "Bond Graph Based Automated Modeling for Computer-Aided Design of Dynamic Systems". Journal of Mechanical Design 130, nr 4 (19.03.2008). http://dx.doi.org/10.1115/1.2885180.
Pełny tekst źródłaStreszczenie:
This paper introduces research leading to a computer-aided design tool in which engineering designers can test various design concepts (topologies) in an environment equipped to automatically model the dynamics and conveniently optimize the specified components (given the evaluation criteria defined by human designers). A component repository is developed to store not only the component dynamics models, but also other information such as typical component design constraints and physical constitutive laws. In this paper, automated modeling of design configurations is introduced through a design representation called a conceptual dynamics graph (CD graph) and generic models of various components. CD graphs contain the information on how physical components as well as their generic models are topologically connected. A generic component model can accommodate various types of coupling between this component and its environment. This paper also discusses a systematic approach to automatically prepare a mechatronic design problem for the use of optimization to tune the parameters for optimum dynamics. Since genetic algorithms are used for this optimization, this preparation decodes and encodes proper design variables into design genotypes while taking into consideration the design constraints and physical constitutive laws.
21
"Design and Implementation of Hybrid FIR Filters using Vedic Multiplier and Fast Adders". International Journal of Recent Technology and Engineering 8, nr 4 (30.11.2019): 11849–53. http://dx.doi.org/10.35940/ijrte.d9569.118419.
Pełny tekst źródłaStreszczenie:
FIR (Finite Impulse Response) filters play a significant role in the field of Digital Signal Processing (DSP) to eliminate noise suppression in Electro Cardio Graph (ECG), Imaging devices and the signal stored in analog media. So filter evaluation is accomplished to reduce the noise level. The Filter passes only the desired frequency to pass thereby reducing distortion in the processed signal during measurement. The FIR filter comprises of basic units like adders, multipliers and the delay element for its operations.FIR and IIR are the two types of digital filters chosen based on the range of inputs, complexity and size requirement. Multipliers and adders play a vital role in deterring the performance of FIR filter. In this work, we design and analyze different multiplier and adder for high-performance Fir filter implementation. The Vedic Mathematics is the methods containing 16 Sutras to aid fast mental calculations. In this work, we propose modified Anurupye Vedic multiplier methods with Kogge Stone fast adder for implementation in the direct form FIR filter. This approach provides 1.5% decrease in delay and 10.2% reduced in power, hence increasing speed marginally than previous methods. Along with low power consumption in Very High-Speed Hardware Description Language (VHDL), all the adders and the multiplier topologies are Synthesized using (Xilinx Spartan – 6 FPGA) Trainer Kit and the proposed 8 – Tap FIR filter is executed using this Board
22
Yuan, Siyu, Hui Huang, Bingyang Cai, Jiwei Li, Miao Zhang i Jie Luo. "Altered metabolic-functional coupling in the epileptogenic network could predict surgical outcomes of mesial temporal lobe epilepsy". Frontiers in Neuroscience 17 (8.06.2023). http://dx.doi.org/10.3389/fnins.2023.1165982.
Pełny tekst źródłaStreszczenie:
ObjectiveTo investigate the relationship between glucose metabolism and functional activity in the epileptogenic network of patients with mesial temporal lobe epilepsy (MTLE) and to determine whether this relationship is associated with surgical outcomes.Methods18F-FDG PET and resting-state functional MRI (rs-fMRI) scans were performed on a hybrid PET/MR scanner in 38 MTLE patients with hippocampal sclerosis (MR-HS), 35 MR-negative patients and 34 healthy controls (HC). Glucose metabolism was measured using 18F-FDG PET standardized uptake value ratio (SUVR) relative to cerebellum; Functional activity was obtained by fractional amplitude of low-frequency fluctuation (fALFF). The betweenness centrality (BC) of metabolic covariance network and functional network were calculated using graph theoretical analysis. Differences in SUVR, fALFF, BC and the spatial voxel-wise SUVR-fALFF couplings of the epileptogenic network, consisting of default mode network (DMN) and thalamus, were evaluated by Mann-Whitney U test (using the false discovery rate [FDR] for multiple comparison correction). The top ten SUVR-fALFF couplings were selected by Fisher score to predict surgical outcomes using logistic regression model.ResultsThe results showed decreased SUVR-fALFF coupling in the bilateral middle frontal gyrus (PFDR = 0.0230, PFDR = 0.0296) in MR-HS patients compared to healthy controls. Coupling in the ipsilateral hippocampus was marginally increased (PFDR = 0.0802) in MR-HS patients along with decreased BC of metabolic covariance network and functional network (PFDR = 0.0152; PFDR = 0.0429). With Fisher score ranking, the top ten SUVR-fALFF couplings in regions from DMN and thalamic subnuclei could predict surgical outcomes with the best performance being a combination of ten SUVR-fALFF couplings with an AUC of 0.914.ConclusionThese findings suggest that the altered neuroenergetic coupling in the epileptogenic network is associated with surgical outcomes of MTLE patients, which may provide insight into their pathogenesis and help with preoperative evaluation.
23
L'official, G., M. Vely, A. Guerin, E. Chen, J. Dreyfus, C. Sportouch, E. Oger i E. Donal. "Isolated functional tricuspid regurgitation, how define patient at-risk for event?" European Heart Journal 43, Supplement_2 (1.10.2022). http://dx.doi.org/10.1093/eurheartj/ehac544.131.
Pełny tekst źródłaStreszczenie:
Abstract Introduction Functional tricuspid regurgitation (TR) is a turning point in cardiac diseases. Symptoms typically appear late, and the optimal timing for proposing a valve repair remains a challenge. We sought to analyse the characteristics of right heart remodelling in patients with significant functional TR to identify the parameters that could be used in an easily achievable and fair prognostic model predicting clinical events. Methods We designed a prospective observational French multicentre study including 160 patients with significant functional TR (effective regurgitant orifice area >30mm2) and LVEF >40%. Clinical, echocardiographic, and ECG data were collected at baseline, and at the 1- and 2-year follow-up. The primary outcome was all-cause death or hospitalization for heart failure. Results At 2 years, 56 patients (35%) achieved the primary outcome. The subset with events showed more advanced right heart remodelling at baseline, but similar TR severity. Right atrial volume index (RAVI) and the TAPSE/sPAP ratio, reflecting right-ventricle-pulmonary artery coupling, were 73 mL/m2 and 0.40 versus 64.7 mL/m2 and 0.50 in the event vs event-free group, respectively (both p<0.05). None among all the clinical and imaging parameters tested had a significant group × time interaction. In multivariable analysis, the model including TAPSE/sPAP ratio >0.4 (OR=0.41, 95%CL 0.2 to 0.82) and RAVI >60 mL/m2 (OR=2.13, 95%CL 0.96 to 4.75) permitted the fairest and most parsimonious prognostic evaluation. Conclusion RAVI and TAPSE/sPAP are relevant for predicting the risk for event at 2-year follow-up in patient with an isolated functional TR. Funding Acknowledgement Type of funding sources: None.
24
Ferrando Castagnetto, F., C. Real, I. Vilacosta, M. Pedrera Canal, M. F. Ollarbes Carrero, R. Ricca-Mallada, A. Rivara Capocasale, M. J. Perez Castejon i J. L. Carreras Delgado. "Electromechanical decoupling with multisite onset of mechanical contraction in patients with different underlying heart diseases derived to gated-SPECT". European Heart Journal 41, Supplement_2 (1.11.2020). http://dx.doi.org/10.1093/ehjci/ehaa946.0280.
Pełny tekst źródłaStreszczenie:
Abstract Backgroud/Introduction Varying degrees of left ventricle (LV) mechanical dyssynchrony have been detected in some patients without electrical dyssynchrony. However, the site of onset of ventricular mechanical contraction as part of the electromechanical coupling process has not been fully described. Purpose To characterize LV contractile dynamics associated with multisite onset of mechanical contraction (OMC). Methods Phase histograms at rest were obtained in a sample of consecutive patients referred to 99mTc-MIBI gated-SPECT (radiotracer dose at rest: 925 MBq). Visual interpretation was performed through a semi-quantitative perfusion scale from 0 to 4 in a 17-segment model. Automated analysis included segmental summed rest, stress and difference scores (SRS, SSS and SDS), and also rest and post-stress functional parameters. Applying SyncTool from Emory Cardiac Toolbox® we obtained peak amplitude (PA), standard deviation (PSD) and phase bandwidth (PBW) indexes from resting phase histogram, detecting the site of OMC in LV. Then, we detected the patients with multisite (“multipoint”) OMC, defined as the onset in at least 3 of 17 segments. Latest site of mechanical contraction was recorded in last 10–30 degrees of phase. Histogram indexes were compared with a control group from our sample (n=24) and with controls reported by Chen J (n=90) by paired t test (p=0.05, two tailed). Results Multisite OMC was found in 19/137 patients (14%); affected from chronic coronary artery disease (n=13), hypertensive heart disease (n=2), inflammatory cardiomyopathy (n=1), hypertrophic cardiomyopathy (n=1) and nonischemic dilated cardiomyopathy (n=2). ECG showed left bundle branch block in one case and biventricular pacing in another. Multisite OMC was associated with diabetes (47.3%), lower LVEF (44.2±15.3%) and higher cavitary volumes (104.5±61.4 ml), SRS (17.0±10.7%) and incidence of fixed defects attributed to old infarct (77.8%); p<0.05 for all comparisons. Subjects with multisite OMC and chronic coronary disease (n=13) were 63±13 years old, 54% diabetic, LVEF=39.9±13.6%, telesystolic LV volume=112.4±64.9 ml, SRS=12.5% and SDS=4.2%. All patients with multisite OMC exhibited marked mechanical dyssynchrony at rest (PA=121.7±16.3, PSD=47.6±19.8, PBW=148.3±64.2 degrees (p<0.05 for the comparisons of PSD and PBW with sample controls and for the comparisons of all indexes with reported controls). In 4 of them (21%) a multisite late mechanical contraction was also detected. Conclusions Electromechanical decoupling with “multipoint” OMC is not infrequently found in patients referred to gated-SPECT, even in the absence of wide QRS complex. This subpopulation of patients is characterized by several functional high risk markers. Additional prognostic implications of this mechanical substrate, that seems to be common to several heart diseases, deserves further evaluation in large series subjected to prolonged clinical and physiological follow-up. Funding Acknowledgement Type of funding source: None
25
Hayasaki Porsani, Mariana Yukari, Luiz Eduardo Duarte de Oliveira, Ruthnea Aparecida Lázaro Muzzi, Claudine Botelho De Abreu, Camila Santos Pereira, Vânia Chaves De Figueiredo, Mariana de Resende Coelho i Antonio Carlos Lacreta Junior. "Variability Inter-observer between Three Methods of Electrocardiographic (Conventional, Computerized and Computerized Printed) on Healthy Cats". Acta Scientiae Veterinariae 48 (15.10.2020). http://dx.doi.org/10.22456/1679-9216.97775.
Pełny tekst źródłaStreszczenie:
Background: Electrocardiography is an exam widely used in feline medicine. It consists of recording the electrical activity of the heart in waves representing myocardial depolarization and repolarization. Two electrocardiographic evaluation methods are employed in dogs and cats: computerized and conventional. However, possible differences in ECG results performed by the different methods have been reported. This paper aims to evaluate the observer's interference in the interpretation of the electrocardiographic exams and possible differences between the methods: conventional single channel, computerized screen and computerized printed of healthy cats.Materials, Methods & Results: Electrocardiographic tracings were obtained from 58 healthy cats, aged between 1 and 10 years-old, of both sexes, of the Persian and mixed breed and therefore interpreted by four observers with similar degree of experience. The examinations were performed in a sequential manner, the computerized method first, and then the conventional method. The animals were gently contained in the right lateral decubitus position. The tracings obtained by the conventional method were printed on thermally sensitive graph paper. The computerized method was performed in computer by means of specific software (TEB® ECGPC version 6.2), being the waves delimited by the observer. The tracings were also printed by means of a jet printer, and also interpreted. The morphology of P waves, QRS complexes and T waves were analyzed in the derivations: I, II, III, aVR, aVL and aVF. Heart rate, amplitude and duration of the P, QRS and T waves, PR, QT and heart rate (HR) intervals were calculated in derivation II. Mean electric axis was determined in leads I and III. Comparing the methods, there was a difference observed in the values of P and R waves, QRS complex, QT and PR intervals and T wave polarity. The interpretation of the evaluators presented statistical differences in the duration of the P wave, QRS, QT and HR. The three methods used presented differences during the mean of the interpretation of the evaluators.Discussion: Some factors such as the positioning of the animal and the use of chemical containment may influence the electrocardiographic tracings, as well as variations between electrocardiographic devices. In our study, the non-use of sedation and the use of the same equipment in all animals reduced the variability of the results. The interpretation of the computerized method printed and on the screen presented different results which can be explained by the reduced human visual capacity when compared to the computers. It is known that the interpretation of different tracings by the observers might influence the results of the examination. The evaluators of the present study evaluated the same tracings, but there was a difference in the interpretation of the observers. Regarding the methods, there was a difference between the three methods evaluated in relation to the ST segment. The computerized on-screen method demonstrated in its totality isoelectric ST segments that represent normal pattern for the species. The conventional and computerized printed methods presented results of elevation in ST segments that represent alterations in the diagnosis. There was a difference between the measurements performed by different observers, however this fact did not influence the results of the tests, since the parameters remained within the normality standards for species. It can be concluded that the variation between observers and among the three methods evaluated suggests that the ST segment interpretation is subtle and less influenced when performed in the computerized method.