A method combining information entropy and radial basis function network is proposed for fault automatic diagnosis of reciprocating compressors.Aiming at the current situation that the accuracy rate of reciprocating c...A method combining information entropy and radial basis function network is proposed for fault automatic diagnosis of reciprocating compressors.Aiming at the current situation that the accuracy rate of reciprocating compressor fault diagnosis which depends on manual work in engineering is very low,we apply information entropy evaluation to select the sensitive features and make clear the corresponding relationship of characteristic parameters and failures.This method could reduce the feature dimension.Then,a complete fault diagnosis architecture has been built combining with radial basis function network which has the fast and efficient characteristics.According to the test results using experimental and engineering data,it is observed that the proposed fault diagnosis method improves the accuracy of fault automatic diagnosis effectively and it could improve the practicability of the monitoring system.展开更多
In modern complex systems,real-time regression prediction plays a vital role in performance evaluation and risk warning.Nevertheless,existing methods still face challenges in maintaining stability and predictive accur...In modern complex systems,real-time regression prediction plays a vital role in performance evaluation and risk warning.Nevertheless,existing methods still face challenges in maintaining stability and predictive accuracy under complex conditions.To address these limitations,this study proposes an online prediction approach that integrates event tracking sensitivity analysis with machine learning.Specifically,a real-time event tracking sensitivity analysis method is employed to capture and quantify the impact of key events on system outputs.On this basis,a mutualinformation–based self-extraction mechanism is introduced to construct prior weights,which are then incorporated into a LightGBM prediction model.Furthermore,iterative optimization of the feature selection threshold is performed to enhance both stability and accuracy.Experiments on composite microsensor data demonstrate that the proposed method achieves robust and efficient real-time prediction,with potential extension to industrial monitoring and control applications.展开更多
Background: Polycystic ovary syndrome (PCOS), characterized by ovulatory dysfunction, polycystic ovary(PCO),hyperandrogenism and insulin resistance is the commonest endocrine disorder in women of reproductive age. It ...Background: Polycystic ovary syndrome (PCOS), characterized by ovulatory dysfunction, polycystic ovary(PCO),hyperandrogenism and insulin resistance is the commonest endocrine disorder in women of reproductive age. It is an intriguing pathology that involves the perpetuation of a vicious circle with reproductive, endocrine and metabolic components. We aimed to assess the reproductive features and insulin sensitivity (IS) in infertile women with or without PCOS. Materials and Methods: We carried out a cross-sectional analytic study at the outpatient Obstetrics and Gynaecology Department of the Yaounde Gyneco-obstetric and Pediatrics Hospital, Cameroon from September 1st 2012 to March 31st 2013 giving total study duration of 07 months. Laboratory analyses were carried out at the National Obesity Centre(NOC)of the Yaounde Central Hospital, Cameroon. Results: Overall, 36 infertile females were enrolled, which included 15 diagnosed cases of PCOS according to Rotterdam consensus meeting of 2003 and 21 non PCOS subjects as control. PCOS women were younger than non PCOS women (28.8 ± 5.5 vs. 35.0 ± 4.2 years;p = 0.0004). The majority of the women in the PCOS group were spaniomenorrheic (11/15), and ultrasonographic findings were typical of PCOS. Hirsutism score was higher in the PCOS group with a median of 9 (7 - 13). Insulin sensitivity was impaired in two-thirds of the study population, with 12 women found to be insulin resistant(6 PCOS, 6 non PCOS), 12 patients had intermediate insulin sensitivity(2 PCOS, 10 non PCOS)and 12 insulin sensitive(7 PCOS, 5 non PCOS). Apart from blood glucose levels (p = 0.007), all other anthropometric and biological parameters were not significant. Spearman’s correlation identified fasting plasma glucose and total cholesterol as factors associated with insulin sensitivity in females with PCOS. Impaired fasting glucose was observed in 13 patients with 08 from the PCOS group. Conclusion: We conclude that young age, spaniomenorrhea and hirsutism are common findings in PCOS. Furthermore, our findings suggest that PCOS may be more of systemic metabolic disease than solely a purely gynecologic disorder as described hitherto. Despite normal fasting plasma glucose levels, a good proportion of these women has impaired insulin sensitivity and it is associated with a metabolic syndrome.展开更多
In this paper, we extend our previous study of addressing the important problem of automatically identifying question and non-question segments in Arabic monologues using prosodic features. We propose here two novel c...In this paper, we extend our previous study of addressing the important problem of automatically identifying question and non-question segments in Arabic monologues using prosodic features. We propose here two novel classification approaches to this problem: one based on the use of the powerful type-2 fuzzy logic systems (type-2 FLS) and the other on the use of the discriminative sensitivity-based linear learning method (SBLLM). The use of prosodic features has been used in a plethora of practical applications, including speech-related applications, such as speaker and word recognition, emotion and accent identification, topic and sentence segmentation, and text-to-speech applications. In this paper, we continue to specifically focus on the Arabic language, as other languages have received a lot of attention in this regard. Moreover, we aim to improve the performance of our previously-used techniques, of which the support vector machine (SVM) method was the best performing, by applying the two above-mentioned powerful classification approaches. The recorded continuous speech is first segmented into sentences using both energy and time duration parameters. The prosodic features are then extracted from each sentence and fed into each of the two proposed classifiers so as to classify each sentence as a Question or a Non-Question sentence. Our extensive simulation work, based on a moderately-sized database, showed the two proposed classifiers outperform SVM in all of the experiments carried out, with the type-2 FLS classifier consistently exhibiting the best performance, because of its ability to handle all forms of uncertainties.展开更多
This work presents the “n<sup>th</sup>-Order Feature Adjoint Sensitivity Analysis Methodology for Nonlinear Systems” (abbreviated as “n<sup>th</sup>-FASAM-N”), which will be shown to be the...This work presents the “n<sup>th</sup>-Order Feature Adjoint Sensitivity Analysis Methodology for Nonlinear Systems” (abbreviated as “n<sup>th</sup>-FASAM-N”), which will be shown to be the most efficient methodology for computing exact expressions of sensitivities, of any order, of model responses with respect to features of model parameters and, subsequently, with respect to the model’s uncertain parameters, boundaries, and internal interfaces. The unparalleled efficiency and accuracy of the n<sup>th</sup>-FASAM-N methodology stems from the maximal reduction of the number of adjoint computations (which are considered to be “large-scale” computations) for computing high-order sensitivities. When applying the n<sup>th</sup>-FASAM-N methodology to compute the second- and higher-order sensitivities, the number of large-scale computations is proportional to the number of “model features” as opposed to being proportional to the number of model parameters (which are considerably more than the number of features).When a model has no “feature” functions of parameters, but only comprises primary parameters, the n<sup>th</sup>-FASAM-N methodology becomes identical to the extant n<sup>th</sup> CASAM-N (“n<sup>th</sup>-Order Comprehensive Adjoint Sensitivity Analysis Methodology for Nonlinear Systems”) methodology. Both the n<sup>th</sup>-FASAM-N and the n<sup>th</sup>-CASAM-N methodologies are formulated in linearly increasing higher-dimensional Hilbert spaces as opposed to exponentially increasing parameter-dimensional spaces thus overcoming the curse of dimensionality in sensitivity analysis of nonlinear systems. Both the n<sup>th</sup>-FASAM-N and the n<sup>th</sup>-CASAM-N are incomparably more efficient and more accurate than any other methods (statistical, finite differences, etc.) for computing exact expressions of response sensitivities of any order with respect to the model’s features and/or primary uncertain parameters, boundaries, and internal interfaces.展开更多
This work highlights the unparalleled efficiency of the “n<sup>th</sup>-Order Function/ Feature Adjoint Sensitivity Analysis Methodology for Nonlinear Systems” (n<sup>th</sup>-FASAM-N) by con...This work highlights the unparalleled efficiency of the “n<sup>th</sup>-Order Function/ Feature Adjoint Sensitivity Analysis Methodology for Nonlinear Systems” (n<sup>th</sup>-FASAM-N) by considering the well-known Nordheim-Fuchs reactor dynamics/safety model. This model describes a short-time self-limiting power excursion in a nuclear reactor system having a negative temperature coefficient in which a large amount of reactivity is suddenly inserted, either intentionally or by accident. This nonlinear paradigm model is sufficiently complex to model realistically self-limiting power excursions for short times yet admits closed-form exact expressions for the time-dependent neutron flux, temperature distribution and energy released during the transient power burst. The n<sup>th</sup>-FASAM-N methodology is compared to the extant “n<sup>th</sup>-Order Comprehensive Adjoint Sensitivity Analysis Methodology for Nonlinear Systems” (n<sup>th</sup>-CASAM-N) showing that: (i) the 1<sup>st</sup>-FASAM-N and the 1<sup>st</sup>-CASAM-N methodologies are equally efficient for computing the first-order sensitivities;each methodology requires a single large-scale computation for solving the “First-Level Adjoint Sensitivity System” (1<sup>st</sup>-LASS);(ii) the 2<sup>nd</sup>-FASAM-N methodology is considerably more efficient than the 2<sup>nd</sup>-CASAM-N methodology for computing the second-order sensitivities since the number of feature-functions is much smaller than the number of primary parameters;specifically for the Nordheim-Fuchs model, the 2<sup>nd</sup>-FASAM-N methodology requires 2 large-scale computations to obtain all of the exact expressions of the 28 distinct second-order response sensitivities with respect to the model parameters while the 2<sup>nd</sup>-CASAM-N methodology requires 7 large-scale computations for obtaining these 28 second-order sensitivities;(iii) the 3<sup>rd</sup>-FASAM-N methodology is even more efficient than the 3<sup>rd</sup>-CASAM-N methodology: only 2 large-scale computations are needed to obtain the exact expressions of the 84 distinct third-order response sensitivities with respect to the Nordheim-Fuchs model’s parameters when applying the 3<sup>rd</sup>-FASAM-N methodology, while the application of the 3<sup>rd</sup>-CASAM-N methodology requires at least 22 large-scale computations for computing the same 84 distinct third-order sensitivities. Together, the n<sup>th</sup>-FASAM-N and the n<sup>th</sup>-CASAM-N methodologies are the most practical methodologies for computing response sensitivities of any order comprehensively and accurately, overcoming the curse of dimensionality in sensitivity analysis.展开更多
The classification of pathological voice from healthy voice was studied based upon 27 acoustic features derived from a single sound signal of vowel /a:/. First, the feature space was transferred to reduce the data dim...The classification of pathological voice from healthy voice was studied based upon 27 acoustic features derived from a single sound signal of vowel /a:/. First, the feature space was transferred to reduce the data dimension by principle component analysis (PCA). Then the voice samples were classified according to the reduced PCA parameters by support vector machine (SVM) using radial basis function (RBF) as a kernel function. Meanwhile, by changing the ratio of opposite class samples, the accuracy under different features combinations was tested. Experimental data were provided by the voice database of Massachusetts Eye and Ear Infirmary (MEEI) in which 216 vowel /a:/ samples were collected from subjects of healthy and pathological cases, and tested with 5 fold cross-validation method. The result shows the positive rate of pathological voices was improved from 92% to 98% through the PCA method. STD, Fatr, Tasm, NHR, SEG, and PER are pathology sensitive features in illness detection. Using these sensitive features the accuracy of detection of pathological voice from healthy voice can reach 97%.展开更多
Excellent detonation performances and low sensitivity are prerequisites for the deployment of energetic materials.Exploring the underlying factors that affect impact sensitivity and detonation performances as well as ...Excellent detonation performances and low sensitivity are prerequisites for the deployment of energetic materials.Exploring the underlying factors that affect impact sensitivity and detonation performances as well as exploring how to obtain materials with desired properties remains a long-term challenge.Machine learning with its ability to solve complex tasks and perform robust data processing can reveal the relationship between performance and descriptive indicators,potentially accelerating the development process of energetic materials.In this background,impact sensitivity,detonation performances,and 28 physicochemical parameters for 222 energetic materials from density functional theory calculations and published literature were sorted out.Four machine learning algorithms were employed to predict various properties of energetic materials,including impact sensitivity,detonation velocity,detonation pressure,and Gurney energy.Analysis of Pearson coefficients and feature importance showed that the heat of explosion,oxygen balance,decomposition products,and HOMO energy levels have a strong correlation with the impact sensitivity of energetic materials.Oxygen balance,decomposition products,and density have a strong correlation with detonation performances.Utilizing impact sensitivity of 2,3,4-trinitrotoluene and the detonation performances of 2,4,6-trinitrobenzene-1,3,5-triamine as the benchmark,the analysis of feature importance rankings and statistical data revealed the optimal range of key features balancing impact sensitivity and detonation performances:oxygen balance values should be between-40%and-30%,density should range from 1.66 to 1.72 g/cm^(3),HOMO energy levels should be between-6.34 and-6.31 eV,and lipophilicity should be between-1.0 and 0.1,4.49 and 5.59.These findings not only offer important insights into the impact sensitivity and detonation performances of energetic materials,but also provide a theoretical guidance paradigm for the design and development of new energetic materials with optimal detonation performances and reduced sensitivity.展开更多
The mental health issues of college students have become an increasingly prominent social problem,exerting severe impacts on their academic performance and overall well-being.Early identification of Interpersonal Sens...The mental health issues of college students have become an increasingly prominent social problem,exerting severe impacts on their academic performance and overall well-being.Early identification of Interpersonal Sensitivity(IS)in students serves as an effective approach to detect psychological problems and provide timely intervention.In this study,958 freshmen from higher education institutions in Zhejiang Province were selected as participants.We proposed a Multi-Strategy Artemisinin Optimization(MSAO)algorithm by enhancing the Artemisinin Optimization(AO)framework through the integration of a group-guided elimination strategy and a two-stage consolidation strategy.Subsequently,the MSAO was combined with the Fuzzy K-Nearest Neighbor(FKNN)classifier to develop the bMSAO-FKNN predictive model for assessing college students’IS.The proposed algorithm’s efficacy was validated through the CEC 2017 benchmark test suite,while the model’s performance was evaluated on the IS dataset,achieving an accuracy rate of 97.81%.These findings demonstrate that the bMSAO-FKNN model not only ensures high predictive accuracy but also offers interpretability for IS prediction,making it a valuable tool for mental health monitoring in academic settings.展开更多
Hard disk drives(HDDs)serve as the primary storage devices in modern data centers.Once a failure occurs,it often leads to severe data loss,significantly degrading the reliability of storage systems.Numerous studies ha...Hard disk drives(HDDs)serve as the primary storage devices in modern data centers.Once a failure occurs,it often leads to severe data loss,significantly degrading the reliability of storage systems.Numerous studies have proposed machine learning-based HDD failure prediction models.However,the Self-Monitoring,Analysis,and Reporting Technology(SMART)attributes differ across HDD manufacturers.We define hard drives of the same brand and model as homogeneous HDD groups,and those from different brands or models as heterogeneous HDD groups.In practical engineering scenarios,a data center is often composed of a heterogeneous population of HDDs,spanning multiple vendors and models.Existing research predominantly focuses on homogeneous datasets,ignoring the model’s generalization capability across heterogeneous HDDs.As a result,HDD models with limited samples often suffer from poor training effectiveness and prediction performance.To address this issue,we investigate generalizable SMART predictors across heterogeneous HDD groups.By extracting time-series features within a fixed sliding time window,we propose a Heterogeneous Disk Failure Prediction Method based on Time Series Features(HDFPM)framework.This method is adaptable to HDD models with limited sample sizes,thereby enhancing its applicability and robustness across diverse drive populations.Experimental results show that the proposed model achieves an F1-score of 0.9518 when applied to two different Seagate HDD models,while maintaining the False Positive Rate(FPR)below 1%.After incorporating the Complexity-Ratio Dynamic Time Warping(CDTW)based feature enhancement method,the best prediction model achieves a True Positive Rate(TPR)of up to 0.93 between the two models.For next-day failure prediction across various Seagate models,the model achieves an F1-score of up to 0.8792.Moreover,the experimental results also show that within the same brand,the higher the proportion of shared SMART attributes across different models,the better the prediction performance.In addition,HDFPMdemonstrates the best stability andmost significant performance in heterogeneous environments.展开更多
基于集成学习理论,首次将人工神经网络和极端梯度提升算法进行集成,提出一种全新的算法:HEMNG(hybrid ensemble model based on neural networks and gradient boosting),旨在更准确地预测混凝土抗压强度。采用303组混凝土配合比数据进...基于集成学习理论,首次将人工神经网络和极端梯度提升算法进行集成,提出一种全新的算法:HEMNG(hybrid ensemble model based on neural networks and gradient boosting),旨在更准确地预测混凝土抗压强度。采用303组混凝土配合比数据进行建模,以水胶比、砂率、浆骨比、粉煤灰替代比例和养护龄期5个可解释特征作为输入,抗压强度为输出。为了分析HEMNG模型在抗压强度预测中的优势,采用人工神经网络、极端梯度提升、支持向量机、随机森林等模型进行比较,并将模型迁移到全新数据中,以探究其在未知数据上的泛化能力。基于训练良好的HEMNG模型进行敏感性研究,量化3个重要特征对抗压强度的影响。结果表明:HEMNG模型采用5个可解释特征,可准确、可靠地预测抗压强度,在测试集中预测值与实际值的拟合度为0.961,均方根误差为2.704,模型预测精度和泛化能力均明显优于其他模型;将HEMNG模型迁移到新数据中,强度预测值与实际强度值较为吻合,最大绝对误差仅为7 MPa,模型表现出良好的稳健性;根据模型敏感性研究显示,存在一个最佳砂率使抗压强度达到最大;增大水胶比会降低混凝土抗压强度,最佳砂率会随水胶比增大而减小;随着浆骨比的增大,最佳砂率会表现出先增大后减小的趋势,模型能量化分析各参数对抗压强度的影响。开发的HEMNG模型为评估混凝土抗压强度提供了新的思路和方法。展开更多
基金Supported by the National Basic Research Program of China(973 Program)under Grant(No.2012CB026000)the National High Technology Research and Development Program of China(No.2014AA041806)
文摘A method combining information entropy and radial basis function network is proposed for fault automatic diagnosis of reciprocating compressors.Aiming at the current situation that the accuracy rate of reciprocating compressor fault diagnosis which depends on manual work in engineering is very low,we apply information entropy evaluation to select the sensitive features and make clear the corresponding relationship of characteristic parameters and failures.This method could reduce the feature dimension.Then,a complete fault diagnosis architecture has been built combining with radial basis function network which has the fast and efficient characteristics.According to the test results using experimental and engineering data,it is observed that the proposed fault diagnosis method improves the accuracy of fault automatic diagnosis effectively and it could improve the practicability of the monitoring system.
基金financial support from the National Natural Science Foundation of China(Grants No.U2330206,No.U2230206,and No.62173068)the Natural Science Foundation of Guangxi Province(Grant No.AB24010157)+1 种基金the Sichuan Forestry and Grassland Bureau(Grant Nos.G202206012 and G202206012-2)Sichuan Science and Technology Program(Grant Nos.2024NSFSC1483,2024ZYD0156,2023NSFC1962,and DQ202412).
文摘In modern complex systems,real-time regression prediction plays a vital role in performance evaluation and risk warning.Nevertheless,existing methods still face challenges in maintaining stability and predictive accuracy under complex conditions.To address these limitations,this study proposes an online prediction approach that integrates event tracking sensitivity analysis with machine learning.Specifically,a real-time event tracking sensitivity analysis method is employed to capture and quantify the impact of key events on system outputs.On this basis,a mutualinformation–based self-extraction mechanism is introduced to construct prior weights,which are then incorporated into a LightGBM prediction model.Furthermore,iterative optimization of the feature selection threshold is performed to enhance both stability and accuracy.Experiments on composite microsensor data demonstrate that the proposed method achieves robust and efficient real-time prediction,with potential extension to industrial monitoring and control applications.
文摘Background: Polycystic ovary syndrome (PCOS), characterized by ovulatory dysfunction, polycystic ovary(PCO),hyperandrogenism and insulin resistance is the commonest endocrine disorder in women of reproductive age. It is an intriguing pathology that involves the perpetuation of a vicious circle with reproductive, endocrine and metabolic components. We aimed to assess the reproductive features and insulin sensitivity (IS) in infertile women with or without PCOS. Materials and Methods: We carried out a cross-sectional analytic study at the outpatient Obstetrics and Gynaecology Department of the Yaounde Gyneco-obstetric and Pediatrics Hospital, Cameroon from September 1st 2012 to March 31st 2013 giving total study duration of 07 months. Laboratory analyses were carried out at the National Obesity Centre(NOC)of the Yaounde Central Hospital, Cameroon. Results: Overall, 36 infertile females were enrolled, which included 15 diagnosed cases of PCOS according to Rotterdam consensus meeting of 2003 and 21 non PCOS subjects as control. PCOS women were younger than non PCOS women (28.8 ± 5.5 vs. 35.0 ± 4.2 years;p = 0.0004). The majority of the women in the PCOS group were spaniomenorrheic (11/15), and ultrasonographic findings were typical of PCOS. Hirsutism score was higher in the PCOS group with a median of 9 (7 - 13). Insulin sensitivity was impaired in two-thirds of the study population, with 12 women found to be insulin resistant(6 PCOS, 6 non PCOS), 12 patients had intermediate insulin sensitivity(2 PCOS, 10 non PCOS)and 12 insulin sensitive(7 PCOS, 5 non PCOS). Apart from blood glucose levels (p = 0.007), all other anthropometric and biological parameters were not significant. Spearman’s correlation identified fasting plasma glucose and total cholesterol as factors associated with insulin sensitivity in females with PCOS. Impaired fasting glucose was observed in 13 patients with 08 from the PCOS group. Conclusion: We conclude that young age, spaniomenorrhea and hirsutism are common findings in PCOS. Furthermore, our findings suggest that PCOS may be more of systemic metabolic disease than solely a purely gynecologic disorder as described hitherto. Despite normal fasting plasma glucose levels, a good proportion of these women has impaired insulin sensitivity and it is associated with a metabolic syndrome.
文摘In this paper, we extend our previous study of addressing the important problem of automatically identifying question and non-question segments in Arabic monologues using prosodic features. We propose here two novel classification approaches to this problem: one based on the use of the powerful type-2 fuzzy logic systems (type-2 FLS) and the other on the use of the discriminative sensitivity-based linear learning method (SBLLM). The use of prosodic features has been used in a plethora of practical applications, including speech-related applications, such as speaker and word recognition, emotion and accent identification, topic and sentence segmentation, and text-to-speech applications. In this paper, we continue to specifically focus on the Arabic language, as other languages have received a lot of attention in this regard. Moreover, we aim to improve the performance of our previously-used techniques, of which the support vector machine (SVM) method was the best performing, by applying the two above-mentioned powerful classification approaches. The recorded continuous speech is first segmented into sentences using both energy and time duration parameters. The prosodic features are then extracted from each sentence and fed into each of the two proposed classifiers so as to classify each sentence as a Question or a Non-Question sentence. Our extensive simulation work, based on a moderately-sized database, showed the two proposed classifiers outperform SVM in all of the experiments carried out, with the type-2 FLS classifier consistently exhibiting the best performance, because of its ability to handle all forms of uncertainties.
文摘This work presents the “n<sup>th</sup>-Order Feature Adjoint Sensitivity Analysis Methodology for Nonlinear Systems” (abbreviated as “n<sup>th</sup>-FASAM-N”), which will be shown to be the most efficient methodology for computing exact expressions of sensitivities, of any order, of model responses with respect to features of model parameters and, subsequently, with respect to the model’s uncertain parameters, boundaries, and internal interfaces. The unparalleled efficiency and accuracy of the n<sup>th</sup>-FASAM-N methodology stems from the maximal reduction of the number of adjoint computations (which are considered to be “large-scale” computations) for computing high-order sensitivities. When applying the n<sup>th</sup>-FASAM-N methodology to compute the second- and higher-order sensitivities, the number of large-scale computations is proportional to the number of “model features” as opposed to being proportional to the number of model parameters (which are considerably more than the number of features).When a model has no “feature” functions of parameters, but only comprises primary parameters, the n<sup>th</sup>-FASAM-N methodology becomes identical to the extant n<sup>th</sup> CASAM-N (“n<sup>th</sup>-Order Comprehensive Adjoint Sensitivity Analysis Methodology for Nonlinear Systems”) methodology. Both the n<sup>th</sup>-FASAM-N and the n<sup>th</sup>-CASAM-N methodologies are formulated in linearly increasing higher-dimensional Hilbert spaces as opposed to exponentially increasing parameter-dimensional spaces thus overcoming the curse of dimensionality in sensitivity analysis of nonlinear systems. Both the n<sup>th</sup>-FASAM-N and the n<sup>th</sup>-CASAM-N are incomparably more efficient and more accurate than any other methods (statistical, finite differences, etc.) for computing exact expressions of response sensitivities of any order with respect to the model’s features and/or primary uncertain parameters, boundaries, and internal interfaces.
文摘This work highlights the unparalleled efficiency of the “n<sup>th</sup>-Order Function/ Feature Adjoint Sensitivity Analysis Methodology for Nonlinear Systems” (n<sup>th</sup>-FASAM-N) by considering the well-known Nordheim-Fuchs reactor dynamics/safety model. This model describes a short-time self-limiting power excursion in a nuclear reactor system having a negative temperature coefficient in which a large amount of reactivity is suddenly inserted, either intentionally or by accident. This nonlinear paradigm model is sufficiently complex to model realistically self-limiting power excursions for short times yet admits closed-form exact expressions for the time-dependent neutron flux, temperature distribution and energy released during the transient power burst. The n<sup>th</sup>-FASAM-N methodology is compared to the extant “n<sup>th</sup>-Order Comprehensive Adjoint Sensitivity Analysis Methodology for Nonlinear Systems” (n<sup>th</sup>-CASAM-N) showing that: (i) the 1<sup>st</sup>-FASAM-N and the 1<sup>st</sup>-CASAM-N methodologies are equally efficient for computing the first-order sensitivities;each methodology requires a single large-scale computation for solving the “First-Level Adjoint Sensitivity System” (1<sup>st</sup>-LASS);(ii) the 2<sup>nd</sup>-FASAM-N methodology is considerably more efficient than the 2<sup>nd</sup>-CASAM-N methodology for computing the second-order sensitivities since the number of feature-functions is much smaller than the number of primary parameters;specifically for the Nordheim-Fuchs model, the 2<sup>nd</sup>-FASAM-N methodology requires 2 large-scale computations to obtain all of the exact expressions of the 28 distinct second-order response sensitivities with respect to the model parameters while the 2<sup>nd</sup>-CASAM-N methodology requires 7 large-scale computations for obtaining these 28 second-order sensitivities;(iii) the 3<sup>rd</sup>-FASAM-N methodology is even more efficient than the 3<sup>rd</sup>-CASAM-N methodology: only 2 large-scale computations are needed to obtain the exact expressions of the 84 distinct third-order response sensitivities with respect to the Nordheim-Fuchs model’s parameters when applying the 3<sup>rd</sup>-FASAM-N methodology, while the application of the 3<sup>rd</sup>-CASAM-N methodology requires at least 22 large-scale computations for computing the same 84 distinct third-order sensitivities. Together, the n<sup>th</sup>-FASAM-N and the n<sup>th</sup>-CASAM-N methodologies are the most practical methodologies for computing response sensitivities of any order comprehensively and accurately, overcoming the curse of dimensionality in sensitivity analysis.
文摘The classification of pathological voice from healthy voice was studied based upon 27 acoustic features derived from a single sound signal of vowel /a:/. First, the feature space was transferred to reduce the data dimension by principle component analysis (PCA). Then the voice samples were classified according to the reduced PCA parameters by support vector machine (SVM) using radial basis function (RBF) as a kernel function. Meanwhile, by changing the ratio of opposite class samples, the accuracy under different features combinations was tested. Experimental data were provided by the voice database of Massachusetts Eye and Ear Infirmary (MEEI) in which 216 vowel /a:/ samples were collected from subjects of healthy and pathological cases, and tested with 5 fold cross-validation method. The result shows the positive rate of pathological voices was improved from 92% to 98% through the PCA method. STD, Fatr, Tasm, NHR, SEG, and PER are pathology sensitive features in illness detection. Using these sensitive features the accuracy of detection of pathological voice from healthy voice can reach 97%.
基金supported by the Fundamental Research Funds for the Central Universities(Grant No.2682024GF019)。
文摘Excellent detonation performances and low sensitivity are prerequisites for the deployment of energetic materials.Exploring the underlying factors that affect impact sensitivity and detonation performances as well as exploring how to obtain materials with desired properties remains a long-term challenge.Machine learning with its ability to solve complex tasks and perform robust data processing can reveal the relationship between performance and descriptive indicators,potentially accelerating the development process of energetic materials.In this background,impact sensitivity,detonation performances,and 28 physicochemical parameters for 222 energetic materials from density functional theory calculations and published literature were sorted out.Four machine learning algorithms were employed to predict various properties of energetic materials,including impact sensitivity,detonation velocity,detonation pressure,and Gurney energy.Analysis of Pearson coefficients and feature importance showed that the heat of explosion,oxygen balance,decomposition products,and HOMO energy levels have a strong correlation with the impact sensitivity of energetic materials.Oxygen balance,decomposition products,and density have a strong correlation with detonation performances.Utilizing impact sensitivity of 2,3,4-trinitrotoluene and the detonation performances of 2,4,6-trinitrobenzene-1,3,5-triamine as the benchmark,the analysis of feature importance rankings and statistical data revealed the optimal range of key features balancing impact sensitivity and detonation performances:oxygen balance values should be between-40%and-30%,density should range from 1.66 to 1.72 g/cm^(3),HOMO energy levels should be between-6.34 and-6.31 eV,and lipophilicity should be between-1.0 and 0.1,4.49 and 5.59.These findings not only offer important insights into the impact sensitivity and detonation performances of energetic materials,but also provide a theoretical guidance paradigm for the design and development of new energetic materials with optimal detonation performances and reduced sensitivity.
文摘The mental health issues of college students have become an increasingly prominent social problem,exerting severe impacts on their academic performance and overall well-being.Early identification of Interpersonal Sensitivity(IS)in students serves as an effective approach to detect psychological problems and provide timely intervention.In this study,958 freshmen from higher education institutions in Zhejiang Province were selected as participants.We proposed a Multi-Strategy Artemisinin Optimization(MSAO)algorithm by enhancing the Artemisinin Optimization(AO)framework through the integration of a group-guided elimination strategy and a two-stage consolidation strategy.Subsequently,the MSAO was combined with the Fuzzy K-Nearest Neighbor(FKNN)classifier to develop the bMSAO-FKNN predictive model for assessing college students’IS.The proposed algorithm’s efficacy was validated through the CEC 2017 benchmark test suite,while the model’s performance was evaluated on the IS dataset,achieving an accuracy rate of 97.81%.These findings demonstrate that the bMSAO-FKNN model not only ensures high predictive accuracy but also offers interpretability for IS prediction,making it a valuable tool for mental health monitoring in academic settings.
基金supported by the Tianjin Manufacturing High Quality Development Special Foundation(No.20232185)the Roycom Foundation(No.70306901).
文摘Hard disk drives(HDDs)serve as the primary storage devices in modern data centers.Once a failure occurs,it often leads to severe data loss,significantly degrading the reliability of storage systems.Numerous studies have proposed machine learning-based HDD failure prediction models.However,the Self-Monitoring,Analysis,and Reporting Technology(SMART)attributes differ across HDD manufacturers.We define hard drives of the same brand and model as homogeneous HDD groups,and those from different brands or models as heterogeneous HDD groups.In practical engineering scenarios,a data center is often composed of a heterogeneous population of HDDs,spanning multiple vendors and models.Existing research predominantly focuses on homogeneous datasets,ignoring the model’s generalization capability across heterogeneous HDDs.As a result,HDD models with limited samples often suffer from poor training effectiveness and prediction performance.To address this issue,we investigate generalizable SMART predictors across heterogeneous HDD groups.By extracting time-series features within a fixed sliding time window,we propose a Heterogeneous Disk Failure Prediction Method based on Time Series Features(HDFPM)framework.This method is adaptable to HDD models with limited sample sizes,thereby enhancing its applicability and robustness across diverse drive populations.Experimental results show that the proposed model achieves an F1-score of 0.9518 when applied to two different Seagate HDD models,while maintaining the False Positive Rate(FPR)below 1%.After incorporating the Complexity-Ratio Dynamic Time Warping(CDTW)based feature enhancement method,the best prediction model achieves a True Positive Rate(TPR)of up to 0.93 between the two models.For next-day failure prediction across various Seagate models,the model achieves an F1-score of up to 0.8792.Moreover,the experimental results also show that within the same brand,the higher the proportion of shared SMART attributes across different models,the better the prediction performance.In addition,HDFPMdemonstrates the best stability andmost significant performance in heterogeneous environments.
文摘基于集成学习理论,首次将人工神经网络和极端梯度提升算法进行集成,提出一种全新的算法:HEMNG(hybrid ensemble model based on neural networks and gradient boosting),旨在更准确地预测混凝土抗压强度。采用303组混凝土配合比数据进行建模,以水胶比、砂率、浆骨比、粉煤灰替代比例和养护龄期5个可解释特征作为输入,抗压强度为输出。为了分析HEMNG模型在抗压强度预测中的优势,采用人工神经网络、极端梯度提升、支持向量机、随机森林等模型进行比较,并将模型迁移到全新数据中,以探究其在未知数据上的泛化能力。基于训练良好的HEMNG模型进行敏感性研究,量化3个重要特征对抗压强度的影响。结果表明:HEMNG模型采用5个可解释特征,可准确、可靠地预测抗压强度,在测试集中预测值与实际值的拟合度为0.961,均方根误差为2.704,模型预测精度和泛化能力均明显优于其他模型;将HEMNG模型迁移到新数据中,强度预测值与实际强度值较为吻合,最大绝对误差仅为7 MPa,模型表现出良好的稳健性;根据模型敏感性研究显示,存在一个最佳砂率使抗压强度达到最大;增大水胶比会降低混凝土抗压强度,最佳砂率会随水胶比增大而减小;随着浆骨比的增大,最佳砂率会表现出先增大后减小的趋势,模型能量化分析各参数对抗压强度的影响。开发的HEMNG模型为评估混凝土抗压强度提供了新的思路和方法。
