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A Real-Time and Ubiquitous Network Attack Detection Based on Deep Belief Network and Support Vector Machine 被引量:8
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作者 Hao Zhang Yongdan Li +2 位作者 Zhihan Lv Arun Kumar Sangaiah Tao Huang 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2020年第3期790-799,共10页
In recent years, network traffic data have become larger and more complex, leading to higher possibilities of network intrusion. Traditional intrusion detection methods face difficulty in processing high-speed network... In recent years, network traffic data have become larger and more complex, leading to higher possibilities of network intrusion. Traditional intrusion detection methods face difficulty in processing high-speed network data and cannot detect currently unknown attacks. Therefore, this paper proposes a network attack detection method combining a flow calculation and deep learning. The method consists of two parts: a real-time detection algorithm based on flow calculations and frequent patterns and a classification algorithm based on the deep belief network and support vector machine(DBN-SVM). Sliding window(SW) stream data processing enables real-time detection, and the DBN-SVM algorithm can improve classification accuracy. Finally, to verify the proposed method, a system is implemented.Based on the CICIDS2017 open source data set, a series of comparative experiments are conducted. The method's real-time detection efficiency is higher than that of traditional machine learning algorithms. The attack classification accuracy is 0.7 percentage points higher than that of a DBN, which is 2 percentage points higher than that of the integrated algorithm boosting and bagging methods. Hence, it is suitable for the real-time detection of high-speed network intrusions. 展开更多
关键词 DEEP BELIEF network(DBN) flow calculation frequent pattern INTRUSION detection SLIDING WINDOW support vector machine(SVM)
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Analysis of rockburst mechanism and warning based on microseismic moment tensors and dynamic Bayesian networks 被引量:4
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作者 Haoyu Mao Nuwen Xu +4 位作者 Xiang Li Biao Li Peiwei Xiao Yonghong Li Peng Li 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2023年第10期2521-2538,共18页
One of the major factors inhibiting the construction of deep underground projects is the risk posed by rockbursts.A study was conducted on the access tunnel of the Shuangjiangkou hydropower station to determine the ev... One of the major factors inhibiting the construction of deep underground projects is the risk posed by rockbursts.A study was conducted on the access tunnel of the Shuangjiangkou hydropower station to determine the evolutionary mechanism of microfractures within the surrounding rock mass during rockburst development and develop a rockburst warning model.The study area was chosen through the combination of field studies with an analysis of the spatial and temporal distribution of microseismic(MS)events.The moment tensor inversion method was adopted to study rockburst mechanism,and a dynamic Bayesian network(DBN)was applied to investigating the sensitivity of MS source parameters for rockburst warnings.A MS multivariable rockburst warning model was proposed and validated using two case studies.The results indicate that fractures in the surrounding rock mass during the development of strain-structure rockbursts initially show shear failure and are then followed by tensile failure.The effectiveness of the DBN-based rockburst warning model was demonstrated using self-validation and K-fold cross-validation.Moment magnitude and source radius are the most sensitive factors based on an investigation of the influence on the parent and child nodes in the model,which can serve as important standards for rockburst warnings.The proposed rockburst warning model was found to be effective when applied to two actual projects. 展开更多
关键词 Microseismic monitoring Moment tensor Dynamic Bayesian network(DBN) Rockburst warning Shuangjiangkou hydropower station
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Multi-channel electromyography pattern classification using deep belief networks for enhanced user experience 被引量:1
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作者 SHIM Hyeon-min LEE Sangmin 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第5期1801-1808,共8页
An enhanced algorithm is proposed to recognize multi-channel electromyography(EMG) patterns using deep belief networks(DBNs). It is difficult to classify the EMG features because an EMG signal has nonlinear and time-v... An enhanced algorithm is proposed to recognize multi-channel electromyography(EMG) patterns using deep belief networks(DBNs). It is difficult to classify the EMG features because an EMG signal has nonlinear and time-varying characteristics.Therefore, in several previous studies, various machine-learning methods have been applied. A DBN is a fast, greedy learning algorithm that can find a fairly good set of weights rapidly, even in deep networks with a large number of parameters and many hidden layers. To evaluate this model, we acquired EMG signals, extracted their features, and then compared the model with the DBN and other conventional classifiers. The accuracy of the DBN is higher than that of the other algorithms. The classification performance of the DBN model designed is approximately 88.60%. It is 7.55%(p=9.82×10-12) higher than linear discriminant analysis(LDA) and 2.89%(p=1.94×10-5) higher than support vector machine(SVM). Further, the DBN is better than shallow learning algorithms or back propagation(BP), and this model is effective for an EMG-based user-interfaced system. 展开更多
关键词 electromyography(EMG) pattern classification feature extraction deep learning deep belief network(DBN)
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Reliability analysis for wireless communication networks via dynamic Bayesian network
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作者 YANG Shunqi ZENG Ying +2 位作者 LI Xiang LI Yanfeng HUANG Hongzhong 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2023年第5期1368-1374,共7页
The dynamic wireless communication network is a complex network that needs to consider various influence factors including communication devices,radio propagation,network topology,and dynamic behaviors.Existing works ... The dynamic wireless communication network is a complex network that needs to consider various influence factors including communication devices,radio propagation,network topology,and dynamic behaviors.Existing works focus on suggesting simplified reliability analysis methods for these dynamic networks.As one of the most popular modeling methodologies,the dynamic Bayesian network(DBN)is proposed.However,it is insufficient for the wireless communication network which contains temporal and non-temporal events.To this end,we present a modeling methodology for a generalized continuous time Bayesian network(CTBN)with a 2-state conditional probability table(CPT).Moreover,a comprehensive reliability analysis method for communication devices and radio propagation is suggested.The proposed methodology is verified by a reliability analysis of a real wireless communication network. 展开更多
关键词 dynamic Bayesian network(DBN) wireless commu-nication network continuous time Bayesian network(CTBN) network reliability
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Dynamic Bayesian Network Based Prognosis in Machining Processes
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作者 董明 杨志波 《Journal of Shanghai Jiaotong university(Science)》 EI 2008年第3期318-322,共5页
Condition based maintenance (CBM) is becoming more and more popular in equipment main-tenance. A prerequisite to widespread deployment of CBM technology and practice in industry is effective diagnostics and prognostic... Condition based maintenance (CBM) is becoming more and more popular in equipment main-tenance. A prerequisite to widespread deployment of CBM technology and practice in industry is effective diagnostics and prognostics. A dynamic Bayesian network (DBN) based prognosis method was investigated to predict the remaining useful life (RUL) for an equipment. First, a DBN based prognosis framework and specific steps for building a DBN based prognosis model were presented. Then, the corresponding inference algorithms for DBN based prognosis were provided. Finally, a prognosis procedure based on particle filtering algorithms was used to predict the RUL of drill-bits of a vertical drilling machine, which is commonly used in industrial process. Preliminary experimental results are promising. 展开更多
关键词 dynamic Bayesian network (DBN) PROGNOSIS remaining useful life
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Modeling spatio-temporal distribution of soil moisture by deep learning-based cellular automata model 被引量:21
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作者 SONG Xiaodong ZHANG Ganlin +3 位作者 LIU Feng LI Decheng ZHAO Yuguo YANG Jinling 《Journal of Arid Land》 SCIE CSCD 2016年第5期734-748,共15页
Soil moisture content (SMC) is a key hydrological parameter in agriculture,meteorology and climate change,and understanding of spatio-temporal distributions of SMC in farmlands is important to address the precise ir... Soil moisture content (SMC) is a key hydrological parameter in agriculture,meteorology and climate change,and understanding of spatio-temporal distributions of SMC in farmlands is important to address the precise irrigation scheduling.However,the hybrid interaction of static and dynamic environmental parameters makes it particularly difficult to accurately and reliably model the distribution of SMC.At present,deep learning wins numerous contests in machine learning and hence deep belief network (DBN) ,a breakthrough in deep learning is trained to extract the transition functions for the simulation of the cell state changes.In this study,we used a novel macroscopic cellular automata (MCA) model by combining DBN to predict the SMC over an irrigated corn field (an area of 22 km^2) in the Zhangye oasis,Northwest China.Static and dynamic environmental variables were prepared with regard to the complex hydrological processes.The widely used neural network,multi-layer perceptron (MLP) ,was utilized for comparison to DBN.The hybrid models (MLP-MCA and DBN-MCA) were calibrated and validated on SMC data within four months,i.e.June to September 2012,which were automatically observed by a wireless sensor network (WSN) .Compared with MLP-MCA,the DBN-MCA model led to a decrease in root mean squared error (RMSE) by 18%.Thus,the differences of prediction errors increased due to the propagating errors of variables,difficulties of knowing soil properties and recording irrigation amount in practice.The sequential Gaussian simulation (s Gs) was performed to assess the uncertainty of soil moisture estimations.Calculated with a threshold of SMC for each grid cell,the local uncertainty of simulated results in the post processing suggested that the probability of SMC less than 25% will be difference in different areas at different time periods.The current results showed that the DBN-MCA model performs better than the MLP-MCA model,and the DBN-MCA model provides a powerful tool for predicting SMC in highly non-linear forms.Moreover,because modeling soil moisture by using environmental variables is gaining increasing popularity,DBN techniques could contribute a lot to enhancing the calibration of MCA-based SMC estimations and hence provide an alternative approach for SMC monitoring in irrigation systems on the basis of canals. 展开更多
关键词 soil moisture soil moisture sensor network macroscopic cellular automata (MCA) deep belief network (DBN) multi-layer perceptron (MLP) uncertainty assessment hydropedology
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Attention mechanism based multi-scale feature extraction of bearing fault diagnosis 被引量:2
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作者 LEI Xue LU Ningyun +2 位作者 CHEN Chuang HU Tianzhen JIANG Bin 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2023年第5期1359-1367,共9页
Effective bearing fault diagnosis is vital for the safe and reliable operation of rotating machinery.In practical applications,bearings often work at various rotational speeds as well as load conditions.Yet,the bearin... Effective bearing fault diagnosis is vital for the safe and reliable operation of rotating machinery.In practical applications,bearings often work at various rotational speeds as well as load conditions.Yet,the bearing fault diagnosis under multiple conditions is a new subject,which needs to be further explored.Therefore,a multi-scale deep belief network(DBN)method integrated with attention mechanism is proposed for the purpose of extracting the multi-scale core features from vibration signals,containing four primary steps:preprocessing of multi-scale data,feature extraction,feature fusion,and fault classification.The key novelties include multi-scale feature extraction using multi-scale DBN algorithm,and feature fusion using attention mecha-nism.The benchmark dataset from University of Ottawa is applied to validate the effectiveness as well as advantages of this method.Furthermore,the aforementioned method is compared with four classical fault diagnosis methods reported in the literature,and the comparison results show that our pro-posed method has higher diagnostic accuracy and better robustness. 展开更多
关键词 bearing fault diagnosis multiple conditions atten-tion mechanism multi-scale data deep belief network(DBN)
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HUID:DBN-Based Fingerprint Localization and Tracking System with Hybrid UWB and IMU 被引量:3
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作者 Junchang Sun Rongyan Gu +4 位作者 Shiyin Li Shuai Ma Hongmei Wang Zongyan Li Weizhou Feng 《China Communications》 SCIE CSCD 2023年第2期139-154,共16页
High-precision localization technology is attracting widespread attention in harsh indoor environments.In this paper,we present a fingerprint localization and tracking system to estimate the locations of the tag based... High-precision localization technology is attracting widespread attention in harsh indoor environments.In this paper,we present a fingerprint localization and tracking system to estimate the locations of the tag based on a deep belief network(DBN).In this system,we propose using coefficients as fingerprints to combine the ultra-wideband(UWB)and inertial measurement unit(IMU)estimation linearly,termed as a HUID system.In particular,the fingerprints are trained by a DBN and estimated by a radial basis function(RBF).However,UWB-based estimation via a trilateral method is severely affected by the non-line-of-sight(NLoS)problem,which limits the localization precision.To tackle this problem,we adopt the random forest classifier to identify line-of-sight(LoS)and NLoS conditions.Then,we adopt the random forest regressor to mitigate ranging errors based on the identification results for improving UWB localization precision.The experimental results show that the mean square error(MSE)of the localization error for the proposed HUID system reduces by 12.96%,50.16%,and 64.92%compared with that of the existing extended Kalman filter(EKF),single UWB,and single IMU estimation methods,respectively. 展开更多
关键词 Ultra-wideband(UWB) inertial measurement unit(IMU) fingerprints positioning NLoS identification estimated errors mitigation deep belief network(DBN) radial basis function(RBF)
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Finite-sensor fault-diagnosis simulation study of gas turbine engine using information entropy and deep belief networks 被引量:6
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作者 De-long FENG Ming-qing XIAO +3 位作者 Ying-xi LIU Hai-fang SONG Zhao YANG Ze-wen HU 《Frontiers of Information Technology & Electronic Engineering》 SCIE EI CSCD 2016年第12期1287-1304,共18页
Precise fault diagnosis is an important part of prognostics and health management. It can avoid accidents, extend the service life of the machine, and also reduce maintenance costs. For gas turbine engine fault diagno... Precise fault diagnosis is an important part of prognostics and health management. It can avoid accidents, extend the service life of the machine, and also reduce maintenance costs. For gas turbine engine fault diagnosis, we cannot install too many sensors in the engine because the operating environment of the engine is harsh and the sensors will not work in high temperature, at high rotation speed, or under high pressure. Thus, there is not enough sensory data from the working engine to diagnose potential failures using existing approaches. In this paper, we consider the problem of engine fault diagnosis using finite sensory data under complicated circumstances, and propose deep belief networks based on information entropy, IE-DBNs, for engine fault diagnosis. We first introduce several information entropies and propose joint complexity entropy based on single signal entropy. Second, the deep belief networks (DBNs) is analyzed and a logistic regression layer is added to the output of the DBNs. Then, information entropy is used in fault diagnosis and as the input for the DBNs. Comparison between the proposed IE-DBNs method and state-of-the-art machine learning approaches shows that the IE-DBNs method achieves higher accuracy. 展开更多
关键词 Deep belief networks dbns Fault diagnosis Information entropy ENGINE
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Improved Deep Belief Network and Model Interpretation Method for Power System Transient Stability Assessment 被引量:21
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作者 Shuang Wu Le Zheng +2 位作者 Wei Hu Rui Yu Baisi Liu 《Journal of Modern Power Systems and Clean Energy》 SCIE EI CSCD 2020年第1期27-37,共11页
The real-time transient stability assessment(TSA)and emergency control are effective measures to suppress accident expansion,prevent system instability,and avoid large-scale power outages in the event of power system ... The real-time transient stability assessment(TSA)and emergency control are effective measures to suppress accident expansion,prevent system instability,and avoid large-scale power outages in the event of power system failure.However,real-time assessment is extremely demanding on computing speed,and the traditional method is not competent.In this paper,an improved deep belief network(DBN)is proposed for the fast assessment of transient stability,which considers the structural characteristics of power system in the construction of loss function.Deep learning has been effective in many fields,but usually is considered as a black-box model.From the perspective of machine learning interpretation,this paper proposes a local linear interpreter(LLI)model,and tries to give a reasonable interpretation of the relationship between the system features and the assessment result,and illustrates the conversion process from the input feature space to the high-dimension representation space.The proposed method is tested on an IEEE new England test system and demonstrated on a regional power system in China.The result demonstrates that the proposed method has rapidity,high accuracy and good interpretability in transient stability assessment. 展开更多
关键词 Transient stability assessment(TSA) representation learning deep BELIEF network(DBN) local linear interpretation(LLI) visualization EMERGENCY control
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Fault Diagnosis of Photovoltaic Array Based on Deep Belief Network Optimized by Genetic Algorithm 被引量:2
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作者 Caixia Tao Xu Wang +1 位作者 Fengyang Gao Min Wang 《Chinese Journal of Electrical Engineering》 CSCD 2020年第3期106-114,共9页
When using deep belief networks(DBN)to establish a fault diagnosis model,the objective function easily falls into a local optimum during the learning and training process due to random initialization of the DBN networ... When using deep belief networks(DBN)to establish a fault diagnosis model,the objective function easily falls into a local optimum during the learning and training process due to random initialization of the DBN network bias and weights,thereby affecting the computational efficiency.To address the problem,a fault diagnosis method based on a deep belief network optimized by genetic algorithm(GA-DBN)is proposed.The method uses the restricted Boltzmann machine reconstruction error to structure the fitness function,and uses the genetic algorithm to optimize the network bias and weight,thus improving the network accuracy and convergence speed.In the experiment,the performance of the model is analyzed from the aspects of reconstruction error,classification accuracy,and time-consuming size.The results are compared with those of back propagation optimized by the genetic algorithm,support vector machines,and DBN.It shows that the proposed method improves the generalization ability of traditional DBN,and has higher recognition accuracy of photovoltaic array faults. 展开更多
关键词 Deep belief network(DBN) fault diagnosis genetic algorithm PV array recognition accuracy
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Extracting Soil Moisture from Fengyun-3D Medium Resolution Spectral Imager-Ⅱ Imagery by Using a Deep Belief Network 被引量:2
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作者 Wenwen WANG Chengming ZHANG +3 位作者 Feng LI Jiaojie SONG Peiqi LI Yuhua ZHANG 《Journal of Meteorological Research》 SCIE CSCD 2020年第4期748-759,共12页
Obtaining continuous and high-quality soil moisture(SM) data is important in scientific research and applications,especially for agriculture, meteorology, and environmental monitoring. With the continuously increasing... Obtaining continuous and high-quality soil moisture(SM) data is important in scientific research and applications,especially for agriculture, meteorology, and environmental monitoring. With the continuously increasing number of artificial satellites in China, the acquisition of SM data from remote sensing images has received increasing attention.In this study, we constructed an SM inversion model by using a deep belief network(DBN) to extract SM data from Fengyun-3 D(FY-3 D) Medium Resolution Spectral Imager-Ⅱ(MERSI-Ⅱ) imagery;we named this model SM-DBN.The SM-DBN consists of two subnetworks: one for temperature and the other for SM. In the temperature subnetwork, bands 1, 2, 3, 4, 24, and 25 of the FY-3 D MERSI-Ⅱ imagery, which are relevant to temperature, were used as inputs while land surface temperatures(LST) obtained from ground stations were used as the expected output value when training the model. In the SM subnetwork, the input data included LSTs generated from the temperature subnetwork, normalized difference vegetation index(NDVI), and enhanced vegetation index(EVI);and the SM data obtained from ground stations were used as the expected outputs. We selected the Ningxia Hui Autonomous Region of China as the study area and used selected MERSI-Ⅱ images and in-situ observation station data from 2018 to 2019 to develop our dataset. The results of the SM-DBN were validated by using in-situ SM data as a reference, and its performance was also compared with those of the linear regression(LR) and back propagation(BP) neural network models. The overall accuracy of these models was measured by using the root mean square error(RMSE) of the differences between the model results and in-situ SM observation data. The RMSE of the LR, BP neural network, and SM-DBN models were 0.101, 0.083, and 0.032, respectively. These results suggest that the SM-DBN model significantly outperformed the other two models. 展开更多
关键词 deep learning deep belief network(DBN) Fengyun-3D(FY-3D) Medium Resolution Spectral Imager-Ⅱ(MERSI-Ⅱ)Imagery data fitting soil moisture(SM) Ningxia
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Developing Soft Sensors for Polymer Melt Index in an Industrial Polymerization Process Using Deep Belief Networks
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作者 Chang-Hao Zhu Jie Zhang 《International Journal of Automation and computing》 EI CSCD 2020年第1期44-54,共11页
This paper presents developing soft sensors for polymer melt index in an industrial polymerization process by using deep belief network(DBN).The important quality variable melt index of polypropylene is hard to measur... This paper presents developing soft sensors for polymer melt index in an industrial polymerization process by using deep belief network(DBN).The important quality variable melt index of polypropylene is hard to measure in industrial processes.Lack of online measurement instruments becomes a problem in polymer quality control.One effective solution is to use soft sensors to estimate the quality variables from process data.In recent years,deep learning has achieved many successful applications in image classification and speech recognition.DBN as one novel technique has strong generalization capability to model complex dynamic processes due to its deep architecture.It can meet the demand of modelling accuracy when applied to actual processes.Compared to the conventional neural networks,the training of DBN contains a supervised training phase and an unsupervised training phase.To mine the valuable information from process data,DBN can be trained by the process data without existing labels in an unsupervised training phase to improve the performance of estimation.Selection of DBN structure is investigated in the paper.The modelling results achieved by DBN and feedforward neural networks are compared in this paper.It is shown that the DBN models give very accurate estimations of the polymer melt index. 展开更多
关键词 Polymer melt index soft sensor deep learning deep belief network(DBN) unsupervised training
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A Novel Evaluation Strategy to Artificial Neural Network Model Based on Bionics
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作者 Sen Tian Jin Zhang +3 位作者 Xuanyu Shu Lingyu Chen Xin Niu You Wang 《Journal of Bionic Engineering》 SCIE EI CSCD 2022年第1期224-239,共16页
With the continuous deepening of Artificial Neural Network(ANN)research,ANN model structure and function are improving towards diversification and intelligence.However,the model is more evaluated from the pros and con... With the continuous deepening of Artificial Neural Network(ANN)research,ANN model structure and function are improving towards diversification and intelligence.However,the model is more evaluated from the pros and cons of the problem-solving results and the lack of evaluation from the biomimetic aspect of imitating neural networks is not inclusive enough.Hence,a new ANN models evaluation strategy is proposed from the perspective of bionics in response to this problem in the paper.Firstly,four classical neural network models are illustrated:Back Propagation(BP)network,Deep Belief Network(DBN),LeNet5 network,and olfactory bionic model(KIII model),and the neuron transmission mode and equation,network structure,and weight updating principle of the models are analyzed qualitatively.The analysis results show that the KIII model comes closer to the actual biological nervous system compared with other models,and the LeNet5 network simulates the nervous system in depth.Secondly,evaluation indexes of ANN are constructed from the perspective of bionics in this paper:small-world,synchronous,and chaotic characteristics.Finally,the network model is quantitatively analyzed by evaluation indexes from the perspective of bionics.The experimental results show that the DBN network,LeNet5 network,and BP network have synchronous characteristics.And the DBN network and LeNet5 network have certain chaotic characteristics,but there is still a certain distance between the three classical neural networks and actual biological neural networks.The KIII model has certain small-world characteristics in structure,and its network also exhibits synchronization characteristics and chaotic characteristics.Compared with the DBN network,LeNet5 network,and the BP network,the KIII model is closer to the real biological neural network. 展开更多
关键词 Artificial neural network(ANN) Back Propagation(BP)network Deep Belief network(DBN) LeNet5 network Olfactory bionic model(KIII model) Small world Chaos SYNCHRONOUS
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Post-COVID effect on heart after recovery based on hybrid EfficientNet-DBN with multilevel classification using ECG images
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作者 Mohammed Abdul Basith Ali Khan Edara Sreenivasa Reddy 《EngMedicine》 2024年第2期4-15,共12页
The highly contagious and dangerous virus known as COVID-19 is caused by severe acute respiratory syndrome(SARS),which is disseminated worldwide.Heart disease is a major cause of death worldwide.One year after the COV... The highly contagious and dangerous virus known as COVID-19 is caused by severe acute respiratory syndrome(SARS),which is disseminated worldwide.Heart disease is a major cause of death worldwide.One year after the COVID-19 pandemic,the risk of heart issues is considerable.Such heart issues involve irregular heartbeats,heart failure,which is the inability of the heart to pump correctly,and coronary disease,which builds up in the arteries and causes restriction in blood flow,heart attacks,etc.Therefore,classifying this disease at an early stage is crucial.Hence,post-COVID effect on the heart after recovery with multilevel classification was performed using the hybrid EfficientNet+Deep Belief Network(EfficientNet+DBN)designed in this study.The input image obtained from the dataset was delivered for binary image conversion and then allowed for feature extraction.Subsequently,first-level disease classification was performed using the hybrid EfficientNet+DBN to detect whether the disease was in normal or abnormal conditions.If it is categorized as abnormal,a second-level classification is performed using EfficientNet-DBN,which classifies myocardial infarction and COVID-19 patients.The Pearson's correlation coefficient was used for the post-COVID correlation study.The experimental outcome showed that EfficientNet-DBN attained a maximum accuracy of 89.80%,sensitivity of 94.70%,and specificity of 91.80%. 展开更多
关键词 Heart disease Deep learning(DL) Coronavirus Deep belief network(DBN) Restricted Boltzmann machine(RBM)
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A combined risk-based and condition monitoring approach:developing a dynamic model for the case of marine engine lubrication 被引量:1
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作者 Nikolaos P.Ventikos Panagiotis Sotiralis Emmanouil Annetis 《Transportation Safety and Environment》 EI 2022年第3期74-87,共14页
This paper focuses on the creation of a dynamic probabilistic model which simulates deterioration trends of a marine engine lubricationsystem. The approach is based on risk and the implementation is achieved through a... This paper focuses on the creation of a dynamic probabilistic model which simulates deterioration trends of a marine engine lubricationsystem. The approach is based on risk and the implementation is achieved through a dynamic Bayesian network (dBN).Risk can be useful for decision making, while dBNs are a powerful tool for risk modelling and prediction models. The model takesinto account deterioration of engine components, oil degradation and the off-line condition monitoring technique of oil analysis, inthe context of predictive maintenance. The paper aims to efficiently predict probability evolution for main engine lubrication failureand to decide upon the most beneficial schemes from a variety of lubrication oil analysis interval schemes by introducing monetarycosts and producing the risk model. Real data and respective analysis, along with expert elicitation, are utilized for achieving modelquantification, while themodel is materialized through a code in the Matlab environment. Results from the probabilistic model showa realistic simulation for the system and indicate the obvious, that with more frequent oil analyses and respective maintenance orrepairs, the probability of failure drops significantly. However, the results from the risk model highlight that the costs can redefinescheme suggestions, as they can correspond to low probabilities of failure but also to higher costs. A two-month interval scheme issuggested, in contrast to the most preferred practice among shipping companies of a three-month interval. The developed model isin general identified as a failure prediction tool focusing on marine engine lubrication failure. 展开更多
关键词 Risk modelling dynamic Bayesian networks(dbns) condition monitoring predictive maintenance marine engine lubrication oil analysis deterioration model
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A Novel DBN-EFA-CFA-Based Dimensional Reduation for Credit Risk Measurement
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作者 ZHANG Yue HUANG Zhenzhen +1 位作者 SHI Longmei ZOU Jian 《Wuhan University Journal of Natural Sciences》 CAS CSCD 2023年第2期117-128,共12页
Affected by the Federal Reserve's interest rate hike and the downward pressure on the domestic economy,the phenomenon of default is still prominent.The credit risk of the listed companies has become a growing conc... Affected by the Federal Reserve's interest rate hike and the downward pressure on the domestic economy,the phenomenon of default is still prominent.The credit risk of the listed companies has become a growing concern of the community.In this paper we present a novel credit risk measurement method based on a dimensional reduation technique.The method first extracts the risk measure indexes from the basal financial data via dimensional reduation by using deep belief network(DBN),exploratory factor analysis(EFA)and confirmatory factor analysis(CFA)in turn.And then the credit risk is measured by a systemic structural equation model(SEM)and logistic distribution.To validate the proposed method,we employ the financial data of the listed companies from Q12019 to Q22022.The empirical results show its effectiveness on statistical evaluation,assessment on testing samples and credit risk forecasting. 展开更多
关键词 credit risk measurement dimensional reduation deep belief network(DBN) exploratory factor analysis(EFA) confirmatory factor analysis(CFA)
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