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Static-based early-damage detection using symbolic data analysis and unsupervised learning methods

João Pedro SANTOS,Christian CREMONA,André D. ORCESI,Paulo SILVEIRA,Luis CALADO

《结构与土木工程前沿(英文)》 2015年 第9卷 第1期   页码 1-16 doi: 10.1007/s11709-014-0277-3

摘要: A large amount of researches and studies have been recently performed by applying statistical and machine learning techniques for vibration-based damage detection. However, the global character inherent to the limited number of modal properties issued from operational modal analysis may be not appropriate for early-damage, which has generally a local character. The present paper aims at detecting this type of damage by using static SHM data and by assuming that early-damage produces dead load redistribution. To achieve this objective a data driven strategy is proposed, consisting of the combination of advanced statistical and machine learning methods such as principal component analysis, symbolic data analysis and cluster analysis. From this analysis it was observed that, under the noise levels measured on site, the proposed strategy is able to automatically detect stiffness reduction in stay cables reaching at least 1%.

关键词: structural health monitoring     early-damage detection     principal component analysis     symbolic data     symbolic dissimilarity measures     cluster analysis     numerical model     damage simulations    

Effects of DNA damage on oocyte meiotic maturation and early embryonic development

Shen YIN,Junyu MA,Wei SHEN

《农业科学与工程前沿(英文)》 2014年 第1卷 第3期   页码 185-190 doi: 10.15302/J-FASE-2014035

摘要: DNA damage is one of the most common threats to meiotic cells. It has the potential to induce infertility and genetic abnormalities that may be passed to the embryo. Here, we reviewed exogenous factors which could induce DNA damage. Specially, we addressed the different effects of DNA damage on mouse oocytes and embryonic development. Complex DNA damage, double-strand breaks, represents a more difficult repair process and involves various repair pathways. Understanding the mechanisms involved in DNA damage responses may improve therapeutic strategies for ovarian cancer and fertility preservation.

关键词: DNA damage     double-strand breaks (DSBs)     oocyte     embryo    

Damage detection in beam-like structures using static shear energy redistribution

《结构与土木工程前沿(英文)》 2022年 第16卷 第12期   页码 1552-1564 doi: 10.1007/s11709-022-0903-4

摘要: In this study, a static shear energy algorithm is presented for the damage assessment of beam-like structures. According to the energy release principle, the strain energy of a damaged element suddenly changes when structural damage occurs. Therefore, the change in the static shear energy is employed to determine the damage locations in beam-like structures. The static shear energy is derived from the spectral factorization of the elementary stiffness matrix and structural deflection variation. The advantage of using shear energy as opposed to total energy is that only a few deflection data points of the beam structure are required during the process of damage identification. Another advantage of the proposed approach is that damage detection can be performed without establishing a structural finite-element model in advance. The proposed technique is first validated using a numerical example with single, multiple, and adjacent damage scenarios. A channel steel beam and rectangular concrete beam are employed as experimental cases to further verify the proposed approach. The results of the simulation and experiment examples indicate that the proposed algorithm provides a simple and effective method for defect localization in beam-like structures.

关键词: damage detection     beam structure     strain energy     static displacement variation     energy damage index    

Multiple damage detection in complex bridges based on strain energy extracted from single point measurement

Alireza ARABHA NAJAFABADI, Farhad DANESHJOO, Hamid Reza AHMADI

《结构与土木工程前沿(英文)》 2020年 第14卷 第3期   页码 722-730 doi: 10.1007/s11709-020-0624-5

摘要: Strain Energy of the structure can be changed with the damage at the damage location. The accurate detection of the damage location using this index in a force system is dependent on the degree of accuracy in determining the structure deformation function before and after damage. The use of modal-based methods to identify damage in complex bridges is always associated with problems due to the need to consider the effects of higher modes and the adverse effect of operational conditions on the extraction of structural modal parameters. In this paper, the deformation of the structure was determined by the concept of influence line using the Betti-Maxwell theory. Then two damage detection indicators were developed based on strain energy variations. These indices were presented separately for bending and torsion changes. Finite element analysis of a five-span concrete curved bridge was done to validate the stated methods. Damage was simulated by decreasing stiffness at different sections of the deck. The response regarding displacement of a point on the deck was measured along each span by passing a moving load on the bridge at very low speeds. Indicators of the strain energy extracted from displacement influence line and the strain energy extracted from the rotational displacement influence line (SERIL) were calculated for the studied bridge. The results show that the proposed methods have well identified the location of the damage by significantly reducing the number of sensors required to record the response. Also, the location of symmetric damages is detected with high resolution using SERIL.

关键词: damage detection     strain energy     influence line     complex bridges     rotation displacement    

An efficient two-stage approach for structural damage detection using meta-heuristic algorithms and group

Hamed FATHNEJAT, Behrouz AHMADI-NEDUSHAN

《结构与土木工程前沿(英文)》 2020年 第14卷 第4期   页码 907-929 doi: 10.1007/s11709-020-0628-1

摘要: In this study, the performance of an efficient two-stage methodology which is applied in a damage detection system using a surrogate model of the structure has been investigated. In the first stage, in order to locate the damage accurately, the performance of the modal strain energy based index for using different numbers of natural mode shapes has been evaluated using the confusion matrix. In the second stage, to estimate the damage extent, the sensitivity of most used modal properties due to damage, such as natural frequency and flexibility matrix is compared with the mean normalized modal strain energy (MNMSE) of suspected damaged elements. Moreover, a modal property change vector is evaluated using the group method of data handling (GMDH) network as a surrogate model during damage extent estimation by optimization algorithm; in this part of methodology, the performance of the three popular optimization algorithms including particle swarm optimization (PSO), bat algorithm (BA), and colliding bodies optimization (CBO) is examined and in this regard, root mean square deviation ( ) based on the modal property change vector has been proposed as an objective function. Furthermore, the effect of noise in the measurement of structural responses by the sensors has also been studied. Finally, in order to achieve the most generalized neural network as a surrogate model, GMDH performance is compared with a properly trained cascade feed-forward neural network (CFNN) with log-sigmoid hidden layer transfer function. The results indicate that the accuracy of damage extent estimation is acceptable in the case of integration of PSO and MNMSE. Moreover, the GMDH model is also more efficient and mimics the behavior of the structure slightly better than CFNN model.

关键词: two-stage method     modal strain energy     surrogate model     GMDH     optimization damage detection    

A new and best approach for early detection of rotor and stator faults in induction motors coupled to

Abderrahim ALLAL,Boukhemis CHETATE

《能源前沿(英文)》 2016年 第10卷 第2期   页码 176-191 doi: 10.1007/s11708-015-0386-2

摘要: Today, induction machines are playing, thanks to their robustness, an important role in world industries. Although they are quite reliable, they have become the target of various types of defects. Thus, for a long time, many research laboratories have been focusing their works on the theme of diagnosis in order to find the most efficient technique to predict a fault in an early stage and to avoid an unplanned stopping in the chain of production and costs ensuing. In this paper, an approach called Park’s vector product approach (PVPA) was proposed which was endowed with a dominant sensitivity in the case in which there would be rotor or stator faults. To show its high sensitivity, it was compared with the classical methods such as motor current signature analysis (MCSA) and techniques studied in recent publications such as motor square current signature analysis (MSCSA), Park’s vector square modulus (PVSM) and Park-Hilbert (P-H) (PVSM ). The proposed technique was based on three main steps. First, the three-phase currents of the induction motor led to a Park’s vector. Secondly, the proposed PVPA was calculated to show the distinguishing spectral signatures of each default and specific frequencies. Finally, simulation and experimental results were presented to confirm the theoretical assumptions.

关键词: induction motor     incipient broken bar     extended Park’s vector approach     spectral analysis     inter-turn short-circuit     Hilbert transform    

Detection of oxidative stress and DNA damage in freshwater snail

Daoud Ali, Huma Ali, Saud Alifiri, Saad Alkahtani, Abdullah A Alkahtane, Shaik Althaf Huasain

《环境科学与工程前沿(英文)》 2018年 第12卷 第5期 doi: 10.1007/s11783-018-1039-6

摘要:

Freshwater snail (Lymnea luteola L.) is good bio indicator of water pollution.

Profenofos is tested for its molluscicidal activity against Lymnea luteola L. snail.

Deleterious effects on some oxidative stress were detected.

Profenofos has a genotoxic effect on Lymnea luteola L. snails.

关键词: Acute toxicity     Profenofos     ROS     oxidative stress     DNA damage     Lymnea luteola    

A deep feed-forward neural network for damage detection in functionally graded carbon nanotube-reinforced

《结构与土木工程前沿(英文)》 2021年 第15卷 第6期   页码 1453-1479 doi: 10.1007/s11709-021-0767-z

摘要: This paper proposes a new Deep Feed-forward Neural Network (DFNN) approach for damage detection in functionally graded carbon nanotube-reinforced composite (FG-CNTRC) plates. In the proposed approach, the DFNN model is developed based on a data set containing 20 000 samples of damage scenarios, obtained via finite element (FE) simulation, of the FG-CNTRC plates. The elemental modal kinetic energy (MKE) values, calculated from natural frequencies and translational nodal displacements of the structures, are utilized as input of the DFNN model while the damage locations and corresponding severities are considered as output. The state-of-the art Exponential Linear Units (ELU) activation function and the Adamax algorithm are employed to train the DFNN model. Additionally, in order to enhance the performance of the DFNN model, the mini-batch and early-stopping techniques are applied to the training process. A trial-and-error procedure is implemented to determine suitable parameters of the network such as the number of hidden layers and the number of neurons in each layer. The accuracy and capability of the proposed DFNN model are illustrated through two distinct configurations of the CNT-fibers constituting the FG-CNTRC plates including uniform distribution (UD) and functionally graded-V distribution (FG-VD). Furthermore, the performance and stability of the DFNN model with the consideration of noise effects on the input data are also investigated. Obtained results indicate that the proposed DFNN model is able to give sufficiently accurate damage detection outcomes for the FG-CNTRC plates for both cases of noise-free and noise-influenced data.

关键词: damage detection     deep feed-forward neural networks     functionally graded carbon nanotube-reinforced composite plates     modal kinetic energy    

早期监测肝细胞癌的新型非蛋白生物标志物 Review

Ghassan K. Abou-Alfa, 吴琳, Augusto Villanueva

《工程(英文)》 2021年 第7卷 第10期   页码 1369-1374 doi: 10.1016/j.eng.2021.02.020

摘要:

肝细胞癌(HCC)早期检测是对处于早期阶段的肝细胞癌进行检出的方法,对降低高风险患者的HCC死亡率至关重要。然而,对于早期HCC,目前仍然缺乏具有高度灵敏性和特异性的监测生物标志物。近年来,人们对循环系统中可检测到的肿瘤源性分子特征进行了大量研究,比如循环肿瘤脱氧核糖核酸(ctDNA)和循环肿瘤核糖核酸(ctRNA),以探讨它们作为多种肿瘤类型的候选非侵入性生物标志物的潜力。本文汇总了目前有关早期HCC检测的新方法及应用的研究。

关键词: 肝细胞癌     早期检测     生物标志物     液体活检    

Damage assessment and diagnosis of hydraulic concrete structures using optimization-based machine learning

《结构与土木工程前沿(英文)》   页码 1281-1294 doi: 10.1007/s11709-023-0975-9

摘要: Concrete is widely used in various large construction projects owing to its high durability, compressive strength, and plasticity. However, the tensile strength of concrete is low, and concrete cracks easily. Changes in the concrete structure will result in changes in parameters such as the frequency mode and curvature mode, which allows one to effectively locate and evaluate structural damages. In this study, the characteristics of the curvature modes in concrete structures are analyzed and a method to obtain the curvature modes based on the strain and displacement modes is proposed. Subsequently, various indices for the damage diagnosis of concrete structures based on the curvature mode are introduced. A damage assessment method for concrete structures is established using an artificial bee colony backpropagation neural network algorithm. The proposed damage assessment method for dam concrete structures comprises various modal parameters, such as curvature and frequency. The feasibility and accuracy of the model are evaluated based on a case study of a concrete gravity dam. The results show that the damage assessment model can accurately evaluate the damage degree of concrete structures with a maximum error of less than 2%, which is within the required accuracy range of damage identification and assessment for most concrete structures.

关键词: hydraulic structure     curvature mode     damage detection     artifical neural network     artificial bee colony    

Detection of damage locations and damage steps in pile foundations using acoustic emissions with deep

Alipujiang JIERULA, Tae-Min OH, Shuhong WANG, Joon-Hyun LEE, Hyunwoo KIM, Jong-Won LEE

《结构与土木工程前沿(英文)》 2021年 第15卷 第2期   页码 318-332 doi: 10.1007/s11709-021-0715-y

摘要: The aim of this study is to propose a new detection method for determining the damage locations in pile foundations based on deep learning using acoustic emission data. First, the damage location is simulated using a back propagation neural network deep learning model with an acoustic emission data set acquired from pile hit experiments. In particular, the damage location is identified using two parameters: the pile location ( ) and the distance from the pile cap ( ). This study investigates the influences of various acoustic emission parameters, numbers of sensors, sensor installation locations, and the time difference on the prediction accuracy of and . In addition, correlations between the damage location and acoustic emission parameters are investigated. Second, the damage step condition is determined using a classification model with an acoustic emission data set acquired from uniaxial compressive strength experiments. Finally, a new damage detection and evaluation method for pile foundations is proposed. This new method is capable of continuously detecting and evaluating the damage of pile foundations in service.

关键词: pile foundations     damage location     acoustic emission     deep learning     damage step    

Low-dose CT for lung cancer screening: opportunities and challenges

null

《医学前沿(英文)》 2018年 第12卷 第1期   页码 116-121 doi: 10.1007/s11684-017-0600-1

摘要:

Lung cancer is among the most frequently diagnosed cancers worldwide and the leading cause of cancer death in both males and females. Screening for lung cancer coupled with earlier intervention has long been studied as an approach to mortality reduction. However, minimal progress was achieved until recently, when low-dose spiral computed tomography (LDCT) screening demonstrated a 20% reduction in mortality from lung cancer in a randomized controlled trial (RCT), the National Lung Screening Trial, from the United States. On the basis of this finding, LDCT has been recommended for lung cancer screening in high-risk populations by several clinical guidelines. However, results from the following independent RCTs in Europe failed to show consistent conclusions. In addition, intractable problems gradually emerged with the progress of LDCT screening. This paper summarizes and discusses the main observations and challenges of LDCT screening for lung cancer. Before spreading implementation of LDCT screening, challenges, including high false-positive rates, overdiagnosis, enormous costs, and radiation risk, must be addressed. Complementary biomarkers and technical improvement are expected in the field of lung cancer screening in the near future.

关键词: lung cancer     low-dose computerized tomography     early detection     opportunities     challenges    

Orthopedic management in the polytrauma patient

null

《医学前沿(英文)》 2012年 第6卷 第3期   页码 234-242 doi: 10.1007/s11684-012-0218-2

摘要:

The past century has seen many changes in the management of the polytraumatized orthopedic patient. Early recommendations for non-operative treatment have evolved into early total care (ETC) and damage control orthopedic (DCO) treatment principles. These principles force the treating orthopaedist to take into account multiple patient parameters including hypothermia, coagulopathy and volume status before deciding upon the operative plan. This requires a multidisciplinary approach involving critical care physicians, anesthesiologists and others.

关键词: damage control orthopedics     early total care     polytrauma    

Uncertainty quantification of stability and damage detection parameters of coupled hydrodynamic-ground

Nazim Abdul NARIMAN, Tom LAHMER, Peyman KARAMPOUR

《结构与土木工程前沿(英文)》 2019年 第13卷 第2期   页码 303-323 doi: 10.1007/s11709-018-0462-x

摘要: In this paper, models of the global system of the Koyna dam have been created using ABAQUS software considering the dam-reservoir-foundation interaction. Non coupled models and the coupled models were compared regarding the horizontal displacement of the dam crest and the differential settlement of the dam base in clay foundation. Meta models were constructed and uncertainty quantification process was adopted by the support of Sobol’s sensitivity indices considering five uncertain parameters by exploiting Box-Behnken experimental method. The non coupled models results determined overestimated predicted stability and damage detection in the dam. The rational effects of the reservoir height were very sensitive in the variation of the horizontal displacement of the dam crest with a small interaction effect with the beta viscous damping coefficient of the clay foundation. The modulus of elasticity of the clay foundation was the decisive parameter regarding the variation of the differential settlement of the dam base. The XFEM approach has been used for damage detection in relation with both minimum and maximum values of each uncertain parameter. Finally the effects of clay and rock foundations were determined regarding the resistance against the propagation of cracks in the dam, where the rock foundation was the best.

关键词: massed foundation     hydrodynamic pressure     Box-Behnken method     meta model     Sobol’s sensitivity indices    

Molecular alterations and clinical relevance in esophageal squamous cell carcinoma

null

《医学前沿(英文)》 2013年 第7卷 第4期   页码 401-410 doi: 10.1007/s11684-013-0286-y

摘要:

Esophageal squamous cell carcinoma (ESCC) is one of the most common types of gastrointestinal cancers, and the fourth leading cause of cancer-related deaths in China. Early detection and intervention in time may dramatically increase the survival of the patients by initiating treatment regimens during earlier stages of ESCC or even during precancerous stages. Molecular classification will be useful for subtyping esophageal tumors or precancerous lesions to improve current therapeutics or early intervention of the disease. In this review, we summarize the findings in investigating the molecular alterations and clinical relevance of ESCC.

关键词: esophageal squamous cell carcinoma (ESCC)     early detection     molecular classification     molecular markers    

标题 作者 时间 类型 操作

Static-based early-damage detection using symbolic data analysis and unsupervised learning methods

João Pedro SANTOS,Christian CREMONA,André D. ORCESI,Paulo SILVEIRA,Luis CALADO

期刊论文

Effects of DNA damage on oocyte meiotic maturation and early embryonic development

Shen YIN,Junyu MA,Wei SHEN

期刊论文

Damage detection in beam-like structures using static shear energy redistribution

期刊论文

Multiple damage detection in complex bridges based on strain energy extracted from single point measurement

Alireza ARABHA NAJAFABADI, Farhad DANESHJOO, Hamid Reza AHMADI

期刊论文

An efficient two-stage approach for structural damage detection using meta-heuristic algorithms and group

Hamed FATHNEJAT, Behrouz AHMADI-NEDUSHAN

期刊论文

A new and best approach for early detection of rotor and stator faults in induction motors coupled to

Abderrahim ALLAL,Boukhemis CHETATE

期刊论文

Detection of oxidative stress and DNA damage in freshwater snail

Daoud Ali, Huma Ali, Saud Alifiri, Saad Alkahtani, Abdullah A Alkahtane, Shaik Althaf Huasain

期刊论文

A deep feed-forward neural network for damage detection in functionally graded carbon nanotube-reinforced

期刊论文

早期监测肝细胞癌的新型非蛋白生物标志物

Ghassan K. Abou-Alfa, 吴琳, Augusto Villanueva

期刊论文

Damage assessment and diagnosis of hydraulic concrete structures using optimization-based machine learning

期刊论文

Detection of damage locations and damage steps in pile foundations using acoustic emissions with deep

Alipujiang JIERULA, Tae-Min OH, Shuhong WANG, Joon-Hyun LEE, Hyunwoo KIM, Jong-Won LEE

期刊论文

Low-dose CT for lung cancer screening: opportunities and challenges

null

期刊论文

Orthopedic management in the polytrauma patient

null

期刊论文

Uncertainty quantification of stability and damage detection parameters of coupled hydrodynamic-ground

Nazim Abdul NARIMAN, Tom LAHMER, Peyman KARAMPOUR

期刊论文

Molecular alterations and clinical relevance in esophageal squamous cell carcinoma

null

期刊论文