An Automatic Modal Identification Procedure for the Permanent Dynamic Monitoring of the Sanctuary of Vicoforte

2018 ◽  
Vol 14 (4) ◽  
pp. 630-644 ◽  
Author(s):  
Marica L. Pecorelli ◽  
Rosario Ceravolo ◽  
Rodolfo Epicoco
2018 ◽  
Vol 211 ◽  
pp. 21002
Author(s):  
Gabriele Marrongelli ◽  
Rafaelle Finotti ◽  
Carmelo Gentile ◽  
Flavio Barbosa

Automated modal identification procedures are attracting the interest of the Structural Health Monitoring (SHM) community as those techniques are capable of continuously providing information which are useful to timely assess the health state of a structure. Within this context, the paper presents the development and application of a vibration-based novelty detection strategy using automatically identified resonant frequencies and the Support Vector Machine (SVM) approach. The SVM is a popular technique for forming decision boundaries that separate data into two or more classes without any prior assumptions on the propriety of the data. The developed procedure is exemplified using frequency data collected during the continuous dynamic monitoring of a historic masonry tower that underwent slight permanent variation of the natural frequencies after the occurrence of a far-field earthquake. The obtained results highlight the capability of the novelty strategy to reveal slight damage and to detect anomalies in the structural behaviour.


2018 ◽  
Vol 18 (5-6) ◽  
pp. 1491-1509 ◽  
Author(s):  
Chuan-Zhi Dong ◽  
Ozan Celik ◽  
F Necati Catbas

In this study, a vision-based multi-point structural dynamic monitoring framework is proposed. This framework aims to solve issues in current vision-based structural health monitoring. Limitations are due to manual markers, single-point monitoring, and synchronization between a multiple-camera setup and a sensor network. The proposed method addresses the first issue using virtual markers—features extracted from an image—instead of physical manual markers. The virtual markers can be selected according to each scenario, which makes them versatile. The framework also overcomes the issue of single-point monitoring by utilizing an advanced visual tracking algorithm based on optical flow, allowing multi-point displacement measurements. Besides, a synchronization mechanism between a multiple-camera setup and a sensor network is built. The proposed method is first tested on a grandstand simulator located in the laboratory. The experiment is to verify the performance of displacement measurement of the proposed method and conduct structural identification of the grandstand through multi-point displacement records. The results from the proposed method are then compared to the data gathered by traditional displacement sensors and accelerometers. A second experiment is conducted at a stadium during a football game to validate the feasibility of field application and the operational modal identification of the stadium under human crowd jumping through the measured displacement records. From these experiments, it is concluded that the proposed method can be employed to identify modal parameters for structural health monitoring.


2019 ◽  
Vol 2019 ◽  
pp. 1-18 ◽  
Author(s):  
Lin Cheng ◽  
Fei Tong ◽  
Jie Yang ◽  
Dongjian Zheng

To investigate the time-varying dynamic characteristics of concrete dams under the excitation of large earthquakes for online structural health monitoring and damage evaluation, an online modal identification procedure based on strong-motion records is proposed. The online modal identification of concrete dams is expressed as a subspace tracking problem, and a newly developed recursive stochastic subspace identification (RSSI) method based on the generalized yet another subspace tracker (GYAST) algorithm, which exploits both the accuracy of the subspace identification and fast computational capability, is used to extract the time-varying modal parameters of concrete dams during earthquakes. With the simulated vibration response records, a numerical example is used to verify the accuracy, robustness, and efficiency of the proposed GYAST-based, time-varying modal identification method. Then, the realistic strong-motion records of the Pacoima arch dam are analysed using the proposed modal identification procedure, and the time-varying characteristics of the concrete arch dam during three different earthquakes are analysed.


Author(s):  
R. Camillacci ◽  
C. Valente ◽  
F. Brancaleoni

An identification procedure for a sample class of mechanical system exhibiting non-linear behavior is presented and validated experimentally. The proposed procedure operates on the free-vibration response of the system and is able not only to extract the time-depended modal parameters, but also to identify the functional relationships between modal frequencies and modal amplitudes of oscillation. These relationships depend just on the mechanical characteristics of the system and thus, they characterize entirely the dynamic behavior. An experimental validation of the procedure performed on a physical laboratory system is presented and discussed. The experimental set-up was designed in order to allow for different configurations and hence for different levels of nonlinearity. The comparison between the identified results and the results of a proper analytical model of the system allows for highlighting the sensibility and effectiveness of the proposed procedure.


Author(s):  
Milchakov K. S. ◽  
◽  
Kosagovskaya I. I. ◽  
Kobiyatskaya E. E. ◽  
Rosalieva Yu. Yu. ◽  
...  

2016 ◽  
pp. 41-45
Author(s):  
V.N. Goncharenko ◽  

The aim of the study: was improvement of results of surgical treatment of patients of reproductive age eligibility with hyperplastic processes of endometrium (HPE) through the introduction of individualized treatment algorithm with the use of monopolar radio wave and hysteroscopic endometrial ablation. Materials and methods. The study included 62 women with non-atypical form of hyperplasia of the endometrium who were treated at the Center of General gynecology of the clinical hospital «Feofania», gynecological Department at the city maternity hospital № 3 of Kyiv. Depending on the age group, nature of the pathological process and method of treatment is randomized, the distribution of women according to groups: group 1 – 41 women's reproductive eligibility age netipichnaya forms of endometrial hyperplasia (PHEBA and KGEB), who were subjected to hysteroscopic monopolar endometrial ablation; group 2 – 21 female reproductive eligibility age netipichnaya forms of endometrial hyperplasia (PHEBA and KGEB), which was held radiowave ablation of the endometrium (RHAE). In the 1st group the age of patients ranged from 42 to 54 years, mean age was 49.9±4.7 years. In the 2nd group the age of patients ranged from 41 to 53 years, mean age of 51.6±4.3 years. Results. A comparative analysis of the techniques for hysteroscopic monopolar ablation and RHEE showed the fact that for RHEE used local anesthesia, while carrying out hysteroscopic monopolar ablation was necessary intravenous anesthesia. The duration of the hysteroscopic monopolar endometrial ablation was 28.6±5.5 min, RAE – according to the standard method – 44.3±0.3 min. When performing hysteroscopic monopolar endometrial ablation in 2 patients (3.7%) patients observed the signs of intravasation of fluid, increased blood pressure and tachycardia. This syndrome was successfully docked, but in the future, women have conducted a thorough examination. When you run RHAE intraoperative complications have been identified. Conclusion. 1. Women with netipichnaya forms of endometrial hyperplasia eligibility and late reproductive age who do not have reproductive plans as an alternative to hysterectomy, in the presence of contraindications or ineffectiveness of hormone treatment may be recommended or radiowave monopolar hysteroscopic ablation of the endometrium. 2. Monopolar hysteroscopic endometrial ablation is indicated for women with netipichnaya forms of endometrial hyperplasia, can be used in the presence of submucous form of uterine fibroids, postoperative scars on the uterus, but in the absence of adenomyosis II–III degree. The effectiveness of monopolar hysteroscopic endometrial ablation in women with non-atypical form of hyperplasia of the endometrium is 87.8%. 3. Women after endometrial ablation should be under observation for two years. The method of choice for dynamic monitoring of the condition of the uterus in women who underwent endometrial ablation is transvaginal ultrasound which should be performed after 1, 3, 6, 12 and 24 months of follow up. 4. In case of recurrence of hyperplastic process of the endometrium (bleeding, thickening of the M-mode echo according to the ultrasound) shows a hysteroscopy with a mandatory histopathological examination and verification of the diagnosis. Key words: endometrial hyperplasia, women eligibility age, women of reproductive age, ablation of the endometrium.


Equipment ◽  
2006 ◽  
Author(s):  
O. Balima ◽  
D. Petit ◽  
J. B. Saulnier ◽  
M. Girault ◽  
Y. Favennec

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