Prof. Hyung-Jo Jung Profile

Prof. Hyung-Jo Jung

Professor at KAIST

SPIE Involvement:

Conference Program Committee | Author

Publications (24)

Proceedings Article | 9 May 2024 Presentation + Paper

Optimizing the structural shape of magneto-rheological elastomers for enhanced performance

Youjin Kim, Seohyun Min, Chanwoo Lee, Hyung-Jo Jung

Proceedings Volume 12946, 129461V (2024) https://doi.org/10.1117/12.3010214

KEYWORDS: Magnetism, Materials properties, 3D printing, Vibration, Design, Smart materials, Viscoelasticity

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Proceedings Article | 22 March 2021 Presentation + Paper

Energy harvesting and damping force of the vibration through the regenerative hybrid electrodynamic damper

Youjin Kim, Seungkyung Kye, Hyung-Jo Jung

Proceedings Volume 11588, 115881B (2021) https://doi.org/10.1117/12.2583315

KEYWORDS: Energy harvesting, Signal attenuation, Electrodynamics, Resistance, Electromagnetism, Civil engineering

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Proceedings Article | 22 March 2021 Presentation + Paper

Missing area detection and damage mapping method based on field-of-view estimation in UAV-based bridge inspection

Gi-Hun Gwon, Sungsik Yoon, Jin Hwan Lee, In-Ho Kim, Hyung-Jo Jung

Proceedings Volume 11591, 115911B (2021) https://doi.org/10.1117/12.2583375

KEYWORDS: Unmanned aerial vehicles, Bridges, Inspection, Cameras, Imaging systems, UAV imaging systems, Sensors, Image analysis, Global Positioning System, Optical inspection

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Recently, numerous studies have been conducted on the UAV-based inspection of infrastructure including bridges, mainly in the United States, Europe and Asia. According to preliminary research and pilot projects, UAV-based bridge inspection has advantages such as safety, cost-time efficiency and access to hazardous areas. Also, above all, it enables objective assessment of the condition of the structure from captured images. However, there are several limitations to the practical application of UAV-based bridge inspection. In particular, damage present in areas where images have not been captured can lead to inappropriate condition assessment. Therefore, it is necessary to check whether the UAV has captured all images for the inspection area. In addition, even if damage is identified in the captured image, it is necessary to map where the image is located on the bridge. In this study, a missing area detection and damage mapping methodology based on the estimated field-of-view using sensor data from UAV systems is proposed. The framework of the proposed methodology consists of a total of 4 phases. First, phase 1 is aimed at converting GPS data to the location of the camera during a UAV flight using IMU data. In phase 2, the coordinates of the center point of the image are determined from the gimbal IMU data and working distance. And phase 3 is the process of calculating the field-of-view through the camera's focal length and working distance. In the preceding phases, the coordinates of each image captured by the UAV are determined. Based on these, missing area detection and damage mapping are performed in phase 4. The proposed missing area detection and damage mapping methodology is experimentally validated for concrete shear wall with artificial damages and the actual target bridge. As a result of experimental validation, the proposed methodology detected areas for which image capture was missing and provided a result of mapping the identified damage within adequate accuracy.

Proceedings Article | 27 March 2019 Paper

A new type of electromagnetic system for magnetorheological elastomer (MRE)-based base isolation system

Yongmoon Hwang, Junghoon Lee, Seung-Kyung Kye, Hyung-Jo Jung

Proceedings Volume 10970, 1097031 (2019) https://doi.org/10.1117/12.2522155

KEYWORDS: Electromagnetism, Magnetism, Numerical simulations, System integration, Earthquakes, Power supplies, Smart materials, Attenuators, Resistance, Prototyping

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Proceedings Article | 27 March 2018 Presentation + Paper

Diagnosis of crack damage on structures based on image processing techniques and R-CNN using unmanned aerial vehicle (UAV)

Jin-Hwan Lee, Sung-Sik Yoon, In-Ho Kim, Hyung-Jo Jung

Proceedings Volume 10598, 1059811 (2018) https://doi.org/10.1117/12.2296691

KEYWORDS: Bridges, Image processing, Unmanned aerial vehicles, Inspection, Detection and tracking algorithms, Cameras, Image acquisition, RGB color model, Image classification, Image sensors

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Proceedings Article | 27 March 2018 Paper

Challenging issues and solutions of bridge inspection technology using unmanned aerial vehicles

Hyung-Jo Jung, Jin-Hwan Lee, In-Ho Kim

Proceedings Volume 10598, 1059802 (2018) https://doi.org/10.1117/12.2300957

KEYWORDS: Bridges, Inspection, Unmanned aerial vehicles, Algorithm development, Cameras, Infrared cameras, Imaging devices, Infrared imaging, Safety, Global Positioning System

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Proceedings Article | 16 March 2018 Presentation + Paper

Experimental study on electromagnetic damper with cable vibration control and energy harvesting function

Seung-Kyung Kye, Ho-Yeon Jung, Hyung-Jo Jung

Proceedings Volume 10595, 1059521 (2018) https://doi.org/10.1117/12.2296843

KEYWORDS: Electromagnetism, Energy harvesting, Sensors, Bridges, Vibration control, Manufacturing, Electromechanical design

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Proceedings Article | 11 April 2017 Paper

An energy harvesting system utilizing wind pressure fluctuations on high-rise building envelope

Jae-Chan Park, In-Ho Kim, Seon-Jun Jang, Hyung-Jo Jung

Proceedings Volume 10164, 101642R (2017) https://doi.org/10.1117/12.2263422

KEYWORDS: Energy harvesting, Buildings, Wind measurement, Renewable energy, Computational fluid dynamics, Prototyping, Wind turbine technology, Wind energy, Analytical research, Numerical analysis, Electromagnetism, Protactinium

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Proceedings Article | 20 April 2016 Paper

Likelihood-free Bayesian computation for structural model calibration: a feasibility study

Seung-Seop Jin, Hyung-Jo Jung

Proceedings Volume 9803, 980323 (2016) https://doi.org/10.1117/12.2222029

KEYWORDS: Diagnostics, Bayesian inference, Calibration, Systems modeling, Statistical modeling, Tolerancing, Inverse problems, Error analysis, Monte Carlo methods, Biology, Genetics

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Proceedings Article | 15 April 2016 Paper

Efficiency improvement of a cantilever-type energy harvester using torsional vibration

In-Ho Kim, Seon-Jun Jang, Jeong-Hoi Koo, Hyung-Jo Jung

Proceedings Volume 9799, 97990N (2016) https://doi.org/10.1117/12.2222019

KEYWORDS: Energy harvesting, Energy efficiency, Numerical simulations, Neodymium, Mechanical engineering, Manufacturing, Prototyping, Mechanical efficiency, Civil engineering

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Proceedings Article | 9 March 2014 Paper

Vibration-based structural health monitoring using adaptive statistical method under varying environmental condition

Seung-Seop Jin, Hyung-Jo Jung

Proceedings Volume 9064, 90640T (2014) https://doi.org/10.1117/12.2046088

KEYWORDS: Principal component analysis, Data modeling, Damage detection, Environmental sensing, Statistical analysis, Structural health monitoring, Environmental monitoring, Statistical modeling, Systems modeling, Statistical methods

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It is well known that the dynamic properties of a structure such as natural frequencies depend not only on damage but also on environmental condition (e.g., temperature). The variation in dynamic characteristics of a structure due to environmental condition may mask damage of the structure. Without taking the change of environmental condition into account, false-positive or false-negative damage diagnosis may occur so that structural health monitoring becomes unreliable. In order to address this problem, an approach to construct a regression model based on structural responses considering environmental factors has been usually used by many researchers. The key to success of this approach is the formulation between the input and output variables of the regression model to take into account the environmental variations. However, it is quite challenging to determine proper environmental variables and measurement locations in advance for fully representing the relationship between the structural responses and the environmental variations. One alternative (i.e., novelty detection) is to remove the variations caused by environmental factors from the structural responses by using multivariate statistical analysis (e.g., principal component analysis (PCA), factor analysis, etc.). The success of this method is deeply depending on the accuracy of the description of normal condition. Generally, there is no prior information on normal condition during data acquisition, so that the normal condition is determined by subjective perspective with human-intervention. The proposed method is a novel adaptive multivariate statistical analysis for monitoring of structural damage detection under environmental change. One advantage of this method is the ability of a generative learning to capture the intrinsic characteristics of the normal condition. The proposed method is tested on numerically simulated data for a range of noise in measurement under environmental variation. A comparative study with conventional methods (i.e., fixed reference scheme) demonstrates the superior performance of the proposed method for structural damage detection.

Proceedings Article | 9 March 2014 Paper

Performance enhancement of piezoelectric energy harvesting system using a corrugated cantilever beam

Jeongsu Park, In-ho Kim, SeungSeop Jin, Jeong-Hoi Koo, Hyung-Jo Jung

Proceedings Volume 9057, 90571Y (2014) https://doi.org/10.1117/12.2046579

KEYWORDS: Ferroelectric polymers, Energy harvesting, Beam shaping, Prototyping, Civil engineering, Manufacturing, Numerical simulations, Bridges, Buildings, Mechanical engineering

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Proceedings Article | 19 April 2013 Paper

Active mass damper system employing time delay control algorithm for vibration mitigation of building structure

Dong-Doo Jang, Jeongsu Park, Hyung-Jo Jung

Proceedings Volume 8692, 86923Z (2013) https://doi.org/10.1117/12.2010012

KEYWORDS: Control systems, Earthquakes, Vibration control, Civil engineering, Adaptive control, Bridges, Algorithm development, Servomechanisms, Systems modeling, Numerical integration

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Proceedings Article | 10 April 2013 Paper

A hybrid electromagnetic energy harvesting device for low frequency vibration

Hyung-Jo Jung, In-Ho Kim, Dong Yi Min, Sung-Han Sim, Jeong-Hoi Koo

Proceedings Volume 8688, 86881I (2013) https://doi.org/10.1117/12.2010014

KEYWORDS: Electromagnetism, Energy harvesting, Sensors, Structural health monitoring, Calcium, Civil engineering, Bridges, Energy efficiency, Mechanical efficiency, Prototyping

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Proceedings Article | 3 April 2012 Paper

Experimental valitation of energy harvesting device for civil engineering applications

Hyung-Jo Jung, In-Ho Kim, Jeongsu Park

Proceedings Volume 8345, 83451C (2012) https://doi.org/10.1117/12.915706

KEYWORDS: Sensors, Energy harvesting, Bridges, Civil engineering, Electromagnetism, Structural health monitoring, Wind energy, Power supplies, Environmental sensing, Prototyping

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Proceedings Article | 15 April 2011 Paper

Development of hybrid type pneumatic vibration isolation table by piezo-stack actuator and filtered-X LMS algorithm

Yun-ho Shin, Dong-doo Jang, Seok-jun Moon, Hyung-Jo Jung, Yeong-jong Moon, Chang-kyu Song

Proceedings Volume 7981, 79813H (2011) https://doi.org/10.1117/12.881203

KEYWORDS: Actuators, Vibration isolation, Algorithm development, Filtering (signal processing), Control systems, Optical filters, Finite impulse response filters, Ions, Amplifiers, Electronic filtering

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Proceedings Article | 13 April 2011 Paper

Hybrid wireless smart sensor network for full-scale structural health monitoring of a cable-stayed bridge

Hongki Jo, Sung-Han Sim, Kirill Mechitov, Robin Kim, Jian Li, Parya Moinzadeh, B. Spencer, Jong Woong Park, Soojin Cho, Hyung-Jo Jung, Chung-Bang Yun, Jennifer Rice, Tomonori Nagayama

Proceedings Volume 7981, 798105 (2011) https://doi.org/10.1117/12.880513

KEYWORDS: Sensors, Structural health monitoring, Bridges, Smart sensors, Sensor networks, Neodymium, Environmental monitoring, Environmental sensing, Data communications, Data processing

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Proceedings Article | 1 April 2010 Paper

Feasibility study of wind generator for smart wireless sensor node in cable-stayed bridge

Jong-Woong Park, Hyung-Jo Jung, Hongki Jo, Shinae Jang, Billie Spencer

Proceedings Volume 7647, 764747 (2010) https://doi.org/10.1117/12.853600

KEYWORDS: Sensors, Bridges, Solar energy, Structural health monitoring, Wind energy, Solar cells, Energy harvesting, Wind measurement, Resistance, Wind turbine technology

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Proceedings Article | 1 April 2010 Paper

Structural health monitoring system of a cable-stayed bridge using a dense array of scalable smart sensor network

Soojin Cho, Shin Ae Jang, Hongki Jo, Kirill Mechitov, Jennifer Rice, Hyung-Jo Jung, Chung-Bang Yun, Billie Spencer, Tomonori Nagayama, Juwon Seo

Proceedings Volume 7647, 764707 (2010) https://doi.org/10.1117/12.852272

KEYWORDS: Bridges, Smart sensors, Structural health monitoring, Sensors, Sensor networks, Wind measurement, Data communications, Energy harvesting, Solar cells, Head

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Proceedings Article | 30 March 2009 Paper

MR damper-based semiactive control system using electromagnetic induction device

Hyung-Jo Jung, Dong-Doo Jang, Jeong-Hoi Koo

Proceedings Volume 7292, 72923X (2009) https://doi.org/10.1117/12.815979

KEYWORDS: Control systems, Electromagnetic coupling, Electromagnetism, Sensors, Power supplies, Civil engineering, Sensing systems, Feedback control, Bridges, Numerical simulations

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Magnetorheological (MR) damper-based semiactive control systems can be considered as one of the most advantageous control systems for natural hazard mitigation in the field of civil engineering because MR dampers have many good features such as small power requirement, reliability, and low price to manufacture. Those systems require feedback control and power supply parts to efficiently reduce the structural responses. The control system becomes complex when a lot of MR dampers are applied to large-scale civil structures, such as cable-stayed bridges and high-rise buildings, resulting in difficulties in its implementation and maintenance. To overcome the above difficulties, a new-class MR damper-based control system was recently proposed by replacing feedback control and power supply parts with an electromagnetic induction (EMI) part consisting of permanent magnets and a coil. According to the Faraday's law of electromagnetic induction, an EMI part produces electrical energy (i.e., electromotive force or induced voltage) from mechanical energy (i.e., reciprocal motions of an MR damper), which is proportional to the rate of the change of the movement of a damper. From this characteristic of an EMI part, it might be used as a response sensing device as well as an alternative power supply. In addition, some control algorithms used in the MR damper-based semiactive control systems require the measurement information on the response related to the relative velocity of the damper. In this study, the sensing capability of an EMI part is preliminarily examined for an application to the MR damper-based semiactive control system. To this end, experimental tests are carried out using the real-scale stay cable employing an MR damper with an EMI part. It is demonstrated from the tests that an EMI part could exactly extract the dynamic characteristics of the stay cable so that it might be used as a sensing device for estimating the tension force of the stay cable. In addition, numerical simulations are performed to verify the control performance of the MR damper-based semiactive control system adopting an EMI part as a power supply as well as a velocity sensor and the maximum energy dissipation algorithm, which requires the information on the relative velocity, as a control algorithm. The numerical result validates that the proposed control system can reduce the vibration of the stay cable effectively.

Proceedings Article | 8 April 2008 Paper

Large-scale smart passive system for civil engineering applications

Hyung-Jo Jung, Dong-Doo Jang, Heon-Jae Lee, Sang-Won Cho

Proceedings Volume 6932, 69320T (2008) https://doi.org/10.1117/12.776543

KEYWORDS: Electromagnetic coupling, Civil engineering, Control systems, Magnetism, Electromagnetism, Buildings, Bridges, Manufacturing, Numerical simulations, Design for manufacturability

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Proceedings Article | 8 April 2008 Paper

Integrated design method of MR damper and electromagnetic induction system for structural control

Heon-Jae Lee, Seok-Jun Moon, Hyung-Jo Jung, Young-Cheol Huh, Dong-Doo Jang

Proceedings Volume 6932, 69320S (2008) https://doi.org/10.1117/12.776160

KEYWORDS: Electromagnetic coupling, Control systems, Magnetism, Control systems design, Electromagnetism, Sensors, Head, Manufacturing, Bridges, Buildings

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Magnetorheological (MR) dampers are one of the most advantageous control devices for civil engineering applications to natural hazard mitigation due to many good features such as small power requirement, reliability, and low price to manufacture. To reduce the responses of a structural system by using MR dampers, a control system including a power supply, control algorithm, and sensors is needed. The control system becomes complex, however, when a lot of MR dampers are applied to large-scale civil structures, such as cable-stayed bridges and high-rise buildings. Thus, it is difficult to install and/or maintain the MR damper-based control system. To overcome the above difficulties, a smart passive system was proposed, which is based on an MR damper system. The smart passive system consists of an MR damper and an electromagnetic induction (EMI) system that uses a permanent magnet and a coil. According to the Faraday law of induction, the EMI system that is attached to the MR damper can produce electric energy and the produced energy is applied to the MR damper to vary the damping characteristics of the damper. Thus, the smart passive system does not require any power at all. Besides the output of electric energy is proportional to input loads such as earthquakes, which means the smart passive system has adaptability by itself without any controller or sensors. In this paper, the integrated design method of a large-scale MR damper and Electromagnetic Induction (EMI) system is presented. Since the force of an MR damper is controllable by altering the input current generated from an EMI part, it is necessary to design an MR damper and an EMI part simultaneously. To do this, design parameters of an EMI part consisting of permanent magnet and coil as well as those of an MR damper consisting of a hydraulic-type cylinder and a magnetic circuit that controls the magnetic flux density in a fluid-flow path are considered in the integrated design procedure. As an example, a smart passive control system for reducing stay cable responses is considered in this investigation and it will be fabricated and tested through experiment in the future.

Proceedings Article | 5 April 2006 Paper

MR damper-based smart passive control system for seismic protection of building structures

Hyung-Jo Jung, Kang-Min Choi, Ji-Eun Jang, Sang-Won Cho, In-Won Lee

Proceedings Volume 6174, 61740O (2006) https://doi.org/10.1117/12.657927

KEYWORDS: Control systems, Electromagnetic coupling, Sensors, Electromagnetism, Power supplies, Systems modeling, Fluid dynamics, Earthquakes, Civil engineering, Bridges

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Proceedings Article | 5 April 2006 Paper

A smart passive damping system for stay cables

S. W. Cho, J. S. Jo, J. E. Jang, J. H. Koo, H. J. Jung

Proceedings Volume 6174, 61740Q (2006) https://doi.org/10.1117/12.655183

KEYWORDS: Control systems, Electromagnetic coupling, Sensors, Power supplies, Electromagnetism, Numerical simulations, Magnetism, Bridges, Civil engineering, Smart materials

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