Damage identification of isolators in base-isolated torsionally coupled buildings

Jer-Fu Wang,Chi-Chang Lin,Ming-Chih Huang,Tzu-Kang Lin 국제구조공학회 2013 Smart Structures and Systems, An International Jou Vol.11 No.4

This paper deals with the damage assessment for isolators of base-isolated building systems considering the torsion-coupling (TC) effect by establishing damage indices. The damage indices can indicate the reduction in lateral stiffness of the isolator story as explicit formulas in terms of modal parameters. In addition, the damage location, expressed in terms of the estimated damage index and eccentricities before and after damage, is also presented. Numerical analysis shows that the proposed algorithms are applicable for general base-isolated multi-story TC buildings. A procedure from the analysis of seismic response to the implementation of damage indices is demonstrated by using a numerical case. A system identification technique is employed to extract modal parameters from seismic responses of a building. Results show that the proposed indices are capable of detecting the occurrence of damage and preliminarily estimating the location of damaged isolator.

Damage identification of isolators in base-isolated torsionally coupled buildings

Wang, Jer-Fu,Huang, Ming-Chih,Lin, Chi-Chang,Lin, Tzu-Kang Techno-Press 2013 Smart Structures and Systems, An International Jou Vol.11 No.4

This paper deals with the damage assessment for isolators of base-isolated building systems considering the torsion-coupling (TC) effect by establishing damage indices. The damage indices can indicate the reduction in lateral stiffness of the isolator story as explicit formulas in terms of modal parameters. In addition, the damage location, expressed in terms of the estimated damage index and eccentricities before and after damage, is also presented. Numerical analysis shows that the proposed algorithms are applicable for general base-isolated multi-story TC buildings. A procedure from the analysis of seismic response to the implementation of damage indices is demonstrated by using a numerical case. A system identification technique is employed to extract modal parameters from seismic responses of a building. Results show that the proposed indices are capable of detecting the occurrence of damage and preliminarily estimating the location of damaged isolator.

Extracting parameters of TMD and primary structure from the combined system responses

Chi-Chang Lin,Jer-Fu Wang 국제구조공학회 2015 Smart Structures and Systems, An International Jou Vol.16 No.5

Tuned mass dampers (TMDs) have been a prevalent vibration control device for suppressing excessive vibration because of environmental loadings in contemporary tall buildings since the mid-1970s. A TMD must be tuned to the natural frequency of the primary structure to be effective. In practice, a TMD may be assembled in situ, simultaneously with the building construction. In such a situation, the respective dynamic properties of the TMD device and building cannot be identified to determine the tuning status of the TMD. For this purpose, a methodology was developed to obtain the parameters of the TMD and primary building on the basis of the eigenparameters of any two complex modes of the combined building–TMD system. The theory was derived in state-space to characterize the nonclassical damping feature of the system, and combined with a system identification technique to obtain the system eigenparameters using the acceleration measurements. The proposed procedure was first demonstrated using a numerical verification and then applied to real, experimental data of a large-scale building–TMD system. The results showed that the procedure is capable of identifying the respective parameters of the TMD and primary structure and is applicable in real implementations by using only the acceleration response measurements of the TMD and its located floor.

Vibration control for serviceability enhancement of offshore platforms against environmental loadings

Chih-Shiuan Lin,Feifei Liu,Jigang Zhang,Jer-Fu Wang,Chi-Chang Lin 국제구조공학회 2019 Smart Structures and Systems, An International Jou Vol.24 No.3

Offshore drilling has become a key process for obtaining oil. Offshore platforms have many applications, including oil exploration and production, navigation, ship loading and unloading, and bridge and causeway support. However, vibration problems caused by severe environmental loads, such as ice, wave, wind, and seismic loads, threaten the functionality of platform facilities and the comfort of workers. These concerns may result in piping failures, unsatisfactory equipment reliability, and safety concerns. Therefore, the vibration control of offshore platforms is essential for assuring structural safety, equipment functionality, and human comfort. In this study, an optimal multiple tuned mass damper (MTMD) system was proposed to mitigate the excessive vibration of a three-dimensional offshore platform under ice and earthquake loadings. The MTMD system was designed to control the first few dominant coupled modes. The optimal placement and system parameters of the MTMD are determined based on controlled modal properties. Numerical simulation results show that the proposed MTMD system can effectively reduce the displacement and acceleration responses of the offshore platform, thus improving safety and serviceability. Moreover, this study proposes an optimal design procedure for the MTMD system to determine the optimal location, moving direction, and system parameters of each unit of the tuned mass damper.

Arm Exoskeleton Rehabilitation Robot with Assistive System for Patient after Stroke

Guan De Lee,Wei-Wen Wang,Kai-Wen Lee,Sheng-Yen Lin,Li-Chen Fu,Jin-Shin Lai,Wen-Shiang Chen,Jer-Junn Luh 제어로봇시스템학회 2012 제어로봇시스템학회 국제학술대회 논문집 Vol.2012 No.10

Exercise dosage is proven to be an important factor in the physical treatment. Robot assistive approach can improve the rehabilitation quality and evaluate patient’s recovery quantitatively. This paper presents kinematic structure, assistive control system, and integrated F/T sensor for an upper limb rehabilitation robot. By using the human arm dynamic, there are three rehabilitation modes presented in this paper: active mode, assistive mode, and passive mode. In assistive mode, we have two strategies to implement it. One is to amplify interactive torque, and the other is to apply assist-as-needed concept. The goal of this mode is to assist patients to finish motion tasks. The rehabilitation robot under investigation has 7 degree of freedom (DOF) actuated by DC motors, which are programmed to drive the robot arm in the 3D space. To validate our control design, some realistic experiments are conducted and its satisfactory performance is demonstrated. This work is approved clinical testing by the Department of Health, Executive Yuan, R.O.C. So far, we are demonstrating the effect of our controller.

Classifying Endemic Fagaceae Species in Taiwan using Leaf Images

( Hao-chun Hsu ),( Cheng-hao Lee ),( Chih-kai Yang ),( Fang-hua Chu ),( Ming-jer Tsai ),( Yan-fu Kuo ) 한국농업기계학회 2018 한국농업기계학회 학술발표논문집 Vol.23 No.1

Fagaceae is one of the plant family which dominate the broad-leaved forests in Taiwan and have considerable value in economy and ecology. Traditionally, plant species identification based on leaf morphologies and is conducted using naked-eye observation. This study is proposed to distinguish the Fagaceae species using image processing and machine learning. In this study, leaf images of 10 Fagaceae species were collected. A serial of traits relevant to leaf morphologies, such as morphological, color, shape, and venation traits, were quantified from the leaf images. A support vector machine classifier was then developed to identify the species using the quantified traits. The proposed approach reached an identification accuracy of 95.8%.

Efficacy and Safety of 12 Weeks of Daclatasvir, Asunaprevir Plus Ribavirin for the Treatment of HCV Genotype 1b Infection without Baseline NS5A Resistance-Associated Variants (DARING)-Interim Report

( Ming-lung Yu ),( Chao-hung Hung ),( Yi-hsiang Huang ),( Cheng-yuan Peng ),( Chun-yen Lin ),( Pin-nan Cheng ),( Rong-nan Chien ),( Shih-jer Hsu ),( Chen-hua Liu ),( Jee-fu Huang ),( Chung-feng Huang 대한간학회 2018 춘·추계 학술대회 (KASL) Vol.2018 No.1

Aims: The current study aims to elucidate the treatment efficacy (defined as undetectable HCV RNA throughout 12 weeks of post-treatment follow-up, SVR12) and safety DCV/ASV plus ribavirin for 12 weeks in HCV-1b patients without NS5A RAS. Methods: This is a single-arm, open-label phase 2 study. Seventy directly acting antivirals (DAA)-naïve HCV-1b patients without L31/Y93 RAS are planned to receive daclatasvir (60 mg/ day) and asunaprevir (100 mg twice daily) plus weight-based ribavirin (1000-1200 mg/day) for 12 weeks. After treatment they were followed up for 12 weeks. Results: As of 31 Oct 2017, 58 eligible patients are allocated to treatment, with a mean age of 59.3 years and female predominance (67.2%, 39/58). The mean HCV RNA was 5.87+0.77 log10 IU/mL; 23 patients (39.7 %) had significant hepatic fibrosis (>F2). In the modified intention-to-treat analysis, the rate of undetectable HCV at week 1, week 2, week 4, week 8 and endof- treatment was 25 % (14/56), 84.8 % (39/46), 100 % (46/46), 100 % (38/38) and 100 % (27/27), respectively. Undetectable HCV RNA were observed in all of the patients with HCV RNA assessable 4 weeks (SVR4, 18/18) and 12 weeks (SVR12, 12/12) post treatment. None of the 18 patients who completed the 12-week treatment experienced relapse during post-treatment follow-up. The most common adverse event was fatigue (78.3 %), followed by pruritus (65.2 %) and dizziness (52.2 %), of which were considered as ribavirin related. None of the participating subjects withdrew treatment or follow-up throughout the trial peroid. Three serious adverse events were reported which included urosepsis, appendicitis and left ureteral stone. All were unrelated to the investigating drugs. Conclusions: 12 weeks of DCV/ASV plus ribavirin was highly effective and safe in HCV-1b patients without NS5A RAS in the interim analysis. The satisfactory results would be anticipated in the full patient set.