Prof. Jan-Ming Ko Profile

Prof. Jan-Ming Ko

Associate VP & Dean at Hong Kong Polytechnic Univ

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Author

Publications (37)

Proceedings Article | 17 May 2005 Paper

A bridge structural health monitoring information system based on GIS and DBMS

W. Z. Shi, L. Chen, J. M. Ko, C. Y. Zhao

Proceedings Volume 5765, (2005) https://doi.org/10.1117/12.601441

KEYWORDS: Databases, Bridges, Sensors, Geographic information systems, 3D modeling, Visualization, Structural health monitoring, Data backup, Statistical analysis, Data modeling

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This paper presents a research on the development of a bridge structural health monitoring and information management system (BSHM&IMS) by utilizing geographic information system (GIS) and other related technologies. Based on the dynamic monitored information from various sensors on a bridge, the status of its structural health can be monitored. One of the major issues in this monitoring process is to handle a huge amount of data-both real time and accumulated historical data. The traditional data processes and management methods cannot fully meet the requirements on data process and management for bridge structural health monitoring. Besides the attribute information, the monitored information of a bridge structural health status is highly related to geospatial location. That is, the monitored information can be referenced to a spatial location, for examples, geospatial locations of bridges, geospatial layouts of various sensors on bridges, three-dimensional models of bridges, and fault points of sensors on maps. GIS technology is therefore applied to manage the information in bridge structural health monitoring. The general framework of BSHM&IMS, which is based on an integration of several information technologies, including GIS, database management system, network and others, will be introduced firstly in this paper. For the implementation of the general design, a prototype of BSHM&IMS has been developed and the major solutions will then be described in details. These functions include design of geospatial database structure for bridges, information processing from various sensors, management of a huge amount of monitored data, visualization of bridge information, illustration of warning information of fault points of sensors on three-dimensional models of bridges, and backup and output of important data according to users’ querying conditions. The experimental results demonstrate that the BSHM&IMS is capable to manage huge amounts of monitored data of bridge structural health, including real time and accumulated historical data, effectively.

Proceedings Article | 17 May 2005 Paper

Modeling of a full-scale MR damper and its application in open-loop vibration control of stay cables

Y. F. Duan, J. M. Ko, Y. Q. Ni

Proceedings Volume 5765, (2005) https://doi.org/10.1117/12.599706

KEYWORDS: Vibration control, Bridges, Control systems, Mathematical modeling, Data modeling, Magnetism, Systems modeling, Integration, Nickel, Structural engineering

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Proceedings Article | 17 May 2005 Paper

Design guidelines for open-loop vibration control of stay cables using MR dampers

Y. Q. Ni, J. M. Ko, Y. F. Duan

Proceedings Volume 5765, (2005) https://doi.org/10.1117/12.599641

KEYWORDS: Vibration control, Bridges, Control systems, Mathematical modeling, Control systems design, Magnesium, Commercial off the shelf technology, Nickel, Structural engineering, Aerodynamics

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Proceedings Article | 17 May 2005 Paper

Instrumentation for durability monitoring of a long-span cable-stayed bridge

Y. Q. Ni, X. G. Hua, J. M. Ko, H. F. Zhou

Proceedings Volume 5765, (2005) https://doi.org/10.1117/12.600434

KEYWORDS: Corrosion, Bridges, Sensors, Data acquisition, Computing systems, Humidity, Electrodes, Safety, Structural health monitoring, Embedded systems

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Proceedings Article | 17 May 2005 Paper

Performance of neural networks for simulation and prediction of temperature-induced modal variability

H. F. Zhou, J. M. Ko, Y. Q. Ni

Proceedings Volume 5765, (2005) https://doi.org/10.1117/12.599187

KEYWORDS: Neural networks, Temperature metrology, Data modeling, Bridges, Temperature sensors, Sensors, Damage detection, Device simulation, Environmental sensing, Structural health monitoring

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Proceedings Article | 29 July 2004 Paper

Theoretical and experimental studies on semi-active feedback control of cable vibration using MR dampers

Yuan-Feng Duan, Yi-Qing Ni, Jan-Ming Ko

Proceedings Volume 5391, (2004) https://doi.org/10.1117/12.540897

KEYWORDS: Control systems, Feedback control, Bridges, Matrices, Vibration control, Received signal strength, Numerical simulations, Computer simulations, Sensors, Prototyping

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Proceedings Article | 29 July 2004 Paper

Smart TLCD using synthetic-hydrocarbon-based MR fluid: an experimental study

Yuan-Feng Duan, Jan-Ming Ko, S. Zhan, Yi-Qing Ni

Proceedings Volume 5391, (2004) https://doi.org/10.1117/12.540895

KEYWORDS: Liquids, Magnetism, Prototyping, Magnetorheological finishing, Signal generators, Control systems, Phased array optics, Complex systems, Vibration control, Numerical simulations

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Proceedings Article | 18 August 2003 Paper

Amplitude-dependent frequency and damping identification of bridge cables with MR dampers in different setups

J. M. Ko, Y. F. Duan, Z. Q. Chen, Yi Qing Ni

Proceedings Volume 5057, (2003) https://doi.org/10.1117/12.482378

KEYWORDS: Bridges, Control systems, Vibration control, Data acquisition, Algorithm development, Civil engineering, Smart materials, Nondestructive evaluation, Bismuth, Magnetic resonance imaging

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Proceedings Article | 18 August 2003 Paper

MR damping system on Dongting Lake cable-stayed bridge

Y. Q. Ni, X. Y. Wang, J. M. Ko, Billie Spencer, G. Yang, Z. Q. Chen

Proceedings Volume 5057, (2003) https://doi.org/10.1117/12.498072

KEYWORDS: Bridges, Video, Control systems, Cameras, Nickel, Wind measurement, Aerodynamics, Reliability, Smart materials, Nondestructive evaluation

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Proceedings Article | 18 August 2003 Paper

Formulation of an uncertainty model relating modal parameters and environmental factors by using long-term monitoring data

Y. Q. Ni, J. Y. Wang, T. H. T. Chan, J. M. Ko, K. Chak

Proceedings Volume 5057, (2003) https://doi.org/10.1117/12.482380

KEYWORDS: Temperature metrology, Bridges, Neural networks, Sensors, Data modeling, Environmental sensing, Temperature sensors, Environmental monitoring, Associative arrays, Astatine

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Proceedings Article | 18 August 2003 Paper

Automatic modal identification of cable-supported bridges instrumented with a long-term monitoring system

G. Zheng, T. H. T. Chan, Y. Q. Ni, K. Q. Fan, J. M. Ko

Proceedings Volume 5057, (2003) https://doi.org/10.1117/12.482379

KEYWORDS: Bridges, Environmental sensing, Software development, Sensors, Environmental monitoring, Structural health monitoring, Vibrometry, LabVIEW, Damage detection, Computer programming languages

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Proceedings Article | 28 June 2002 Paper

Field vibration tests of bridge stay cables incorporated with magnetorheological (MR) dampers

Jan Ming Ko, Z. Chen, Gang Zheng, Yi-Qing Ni

Proceedings Volume 4696, (2002) https://doi.org/10.1117/12.472567

KEYWORDS: Bridges, Sensors, Vibration control, Aluminum, Transducers, Data acquisition, Spectral resolution, Laminated object manufacturing, Smart materials, Electronic filtering

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Proceedings Article | 28 June 2002 Paper

Experimental investigation on seismic response control of adjacent buildings using semi-active MR dampers

H.J. Liu, Yi-Qing Ni, Jan Ming Ko

Proceedings Volume 4696, (2002) https://doi.org/10.1117/12.472570

KEYWORDS: Control systems, Buildings, Electroluminescence, Earthquakes, Stochastic processes, Feedback control, Prototyping, Simulink, MATLAB, Environmental sensing

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Proceedings Article | 28 June 2002 Paper

Nonclipping optimal control of randomly excited nonlinear systems using semi-active ER/MR dampers

Jan Ming Ko, Zuguang Ying, Yi-Qing Ni

Proceedings Volume 4696, (2002) https://doi.org/10.1117/12.472556

KEYWORDS: Control systems, Stochastic processes, Computer programming, Complex systems, Control systems design, Diffusion, Differential equations, Process control, Vibration control, Nonlinear control

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Proceedings Article | 28 June 2002 Paper

Damping identification of MR-damped bridge cables from in-situ monitoring under wind-rain-excited conditions

Y.F. Duan, Z. Chen, Yi-Qing Ni, Jan Ming Ko

Proceedings Volume 4696, (2002) https://doi.org/10.1117/12.472573

KEYWORDS: Aluminum, Bridges, Osmium, Sensors, Vibration control, Motion measurement, Video, Cameras, Data acquisition, Iron

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Proceedings Article | 18 June 2002 Paper

GIS-based bridge structural health monitoring and management system

P. Cheng, Wenzhong Shi, C. Liu, Jan Ming Ko

Proceedings Volume 4704, (2002) https://doi.org/10.1117/12.470725

KEYWORDS: Databases, Bridges, Sensors, Geographic information systems, Visualization, Data backup, Data storage, Structural health monitoring, Visual analytics, Statistical analysis

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For monitoring and evaluating structural health for the three long-span cable-supported bridges, namely, Tsing Ma Bridge, Kap Shui Mun Bridge and Ting Kua Bridge in Hong Kong, Wind And Structural Health Monitoring System (WASHMS) has been established by the Highway Department of the local Government in Hong Kong. To investigate the possibilities of further enhancing the functions of the existing system in storage, retrieve and distribute huge amount of monitoring data for the WASHMS, a study of developing GIS-based bridge structural health monitoring and management system is carried out and presented in this paper. This system is developed by integrating GIS, large database and network techniques. The system is able to run on a Local Area Network or Internet. GIS is applied to manage spatial information on location of bridges on a regional map and position of sensors on a 3D bridge model. It also provides users with interactive interface between user and the system. Large database system, such as SQL Sever or Oracle, is used to manage huge amount of dataset captured from the sensors. In the Sever-Side, by using the data input and database maintain module, the raw data come from WASHMS and the analyzed results can be imported into the central database in real time, and is backup from time to time. For those data that are not changed or changed infrequently, such as regional map for bridges, location information and attributes about sensors, a static database is established to store them. In the Client-Side, user can not only access the raw data from various sensors from the central database at any time, but also visualize or even further process the data. Based on above designed prototype of GIS-based bridge structural health monitoring and management system. It is demonstrated by the prototype that the developed system is feasible. Furthermore, the implementation issues including system design, technique solutions, database structure design and function design are also presented in this paper.

Proceedings Article | 18 June 2002 Paper

Implementation issues of novelty detection technique for cable-supported bridges instrumented with a long-term monitoring system

Jian-Yi Wang, Jan Ming Ko, Yi-Qing Ni, Hong Li

Proceedings Volume 4704, (2002) https://doi.org/10.1117/12.470727

KEYWORDS: Bridges, Neural networks, Distance measurement, Sensors, Mahalanobis distance, Finite element methods, Damage detection, Interference (communication), Modulation, Global Positioning System

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Implementation of a sophisticated long-term monitoring system on the Tsing Ma suspension bridge in Hong Kong highlights the necessity of developing practical damage detection methodologies for large-scale civil structures. The novelty detection technique has been demonstrated to be greatly promising for damage occurrence detection of long-span bridge structures in operation with noisy measurement data. Some key issues concerning the implementation of this technique to the instrumented Tsing Ma Bridge are explored in this paper: (i) Selection of modal frequencies in constructing novelty neural network input for structural damage alarming. A novelty detection neural network using natural frequencies of only vertical modes as input vector and a novelty detection neural network using natural frequencies of mixed vertical and lateral/torsional modes as input vector are respectively constructed, and their identification sensitivities are compared; (ii) Definition of distance functions to measure difference between the input and output vectors due to anomaly. Both the Euclidean distance and the Mahalanobis distance are used to define the anomaly metric and their sensitivities to damage are identified; (iii) Construction of a novelty index capable of discerning between the novelty shift due to structural damage and the novelty shift due to inconsistent noise level. The focus of the present study is on developing an improved novelty index which uniquely indicates structural damage rather than anomaly due to change of noise level. The existing novelty index cannot distinguish true damage from anomaly due to inconsistent noise level in training and testing stages. As a result, the sequence shift signaled by such a novelty index is definitely indicative of structural damage only when the noise level is exactly same for the training data and for the testing data in statistical sense. On the contrary, the improved novelty index developed in this study always indicates damage information no matter the training noise level is greater or less than the testing noise level.