• Journal of Korean Institute of Industrial Engineers
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• v.42 no.3
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• pp.241-248
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• 2016

Plant life cycle consists of design, construction, certification, operation, and maintenance phases, and various and enormous plant life cycle data is involved in each phase. Plant life cycle data should be linked with each other based on its proper relationships, so that plant operators can access necessary plant data during their regular operations and maintenance works. Currently, the relationships of plant life cycle data may not be defined explicitly, or they are scattered over several plant information systems. This paper proposes high level design of a plant life cycle data management system based on pre-defined plant life cycle database design. ISO-15926 standard is adapted for the database design. User-interface designs of the plant life cycle data management system are explained based on analysis of plant owners' requirements. A conceptual design of the database is also described with the entity-relationship diagram.

• Smart Structures and Systems
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• v.13 no.2
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• pp.235-255
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• 2014

This paper mainly introduces recently developed technologies pertaining to the design and implementation of Active Mass Damper (AMD) control system on a high-rise building subjected to wind load. Discussions include introduction of real structure and the control system, the establishment of analytical model, the design and optimization of a variety of controllers, the design of time-varying variable gain feedback control strategy for limiting auxiliary mass stroke, and the design and optimization of AMD control devices. The results presented in this paper demonstrate that the proposed AMD control systems can resolve the issues pertaining to insufficient floor stiffness of the building. The control system operates well and has a good sensitivity.

• Journal of the Semiconductor & Display Technology
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• v.18 no.4
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• pp.105-109
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• 2019

LED lighting is used as artificial lighting for plant growth because it has high light efficiency and can radiate light of various wavelengths. In this paper, we have developed new structure LED lighting module to improve the performance of LED lighting for plant growth and proposed a lighting control system that can be controlled wirelessly. The proposed LED lighting module was fabricated using optical lens applied to tunnel light and simulated using Relux program. Results of simulation, we confirmed that the light distribution and average illuminance of the proposed lighting were improved. LED lighting control system was developed to wirelessly control R, G, B, W LED lighting according to plant type and growing season. Therefore, it is expected to provide the optimal lighting environment for plant growth and contribute to the improvement of farm productivity and convenience.

• The Bulletin of The Korean Astronomical Society
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• v.45 no.1
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• pp.66.3-66.3
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• 2020

We present the optical design of Linear Astigmatism Free - Three Mirror System (LAF-TMS) D200 for UVO-Multiband Polarizing Imager System (UVOMPIS). LAF-TMS D200 is the off-axis wide-field telescope with EPD = 200 mm, F/2, and Field of View (FoV) = 2° × 4°. Its optical mirrors are optimized to freeform surfaces for high-quality optical performance over a wide FoV. The proposed mirror holder consists of four aluminum optomechanical modules that have applied for LAF-TMS D150 which is a prototype of the LAF-TMS system. It can accurately mount mirrors and also can sustain from vibration environments. As a feasibility study, quasi-static, modal, harmonic, and random vibration analyses have been performed to LAF-TMS D150 optomechanical structure under the qualification level of the Soyuz-2/Fregat launch system. We evaluate the vibration analysis results in terms of von Mises stress and Margin of Safety.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.8
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• pp.1105-1111
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• 2010

The Korea Atomic Energy Research Institutes has been developing the SMART (System integrated Modular Advanced ReacTor), an environment-friendly nuclear reactor for the generation of electricity and to perform desalination. SMART reactors can be exposed to various external and internal loads caused by seismic and coolant flows. The CRDM(control rod drive mechanism), one of structures of the SMART, is a component which is adjusting inserting amount of a control rod, controlling output of reactor power and in an emergency situation, inserting a control rod to stop the reactor. The purpose of this research is performing the analysis of dynamic characteristic to ensure safety and integrity of structure of CRDM. This paper presents two FE-models, 3-D solid model and simplified Beam model of the CRDM in the coolant, and then compared the results of the dynamic characteristic about the two FE-models using a commercial Finite Element tool, ABAQUS CAE V6.8 and ANSYS V12. Beam 4 and beam 188 of simplified-model were also compared each other. And simplified model is updated for accuracy compare to 3-D solid.

• Smart Structures and Systems
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• v.25 no.3
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• pp.323-335
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• 2020

Magnetorheological elastomer (MRE), a smart material, is an innovative material for base isolation system. It has magnetorheological (MR) effect that can control the stiffness in real-time. In this paper, a new hybrid base isolation system combining two electromagnetic closed circuits and the roller bearing is proposed. In the proposed system, the roller part can support the vertical load. Thus, the MRE part is free from the vertical load and can exhibit the maximum MR effect. The MRE magnetic loop is constructed in the free space of the roller bearing and forms a strong magnetic field. To demonstrate the performance of the proposed hybrid base isolation system, dynamic characteristic tests and performance evaluation were carried out. Dynamic characteristic tests were performed under the extensive range of strain of the MRE and the change of the applied current. Performance evaluation was carried out using the hybrid simulation under five earthquakes (i.e., El Centro, Kobe, Hachinohe, Northridge, and Loma Prieta). Especially, semi-active fuzzy control algorithm was applied and compared with passive type. From the performance evaluation, the comparison shows that the new hybrid base isolation system using fuzzy control algorithm is superior to passive type in reducing the acceleration and displacement responses of a target structure.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.14 no.3
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• pp.193-200
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• 2004

The Active Constrained Layer Damping(ACLD) combines the simplicity and reliability of passive damping with the low weight and high efficiency of active control to attain high damping characteristics. The proposed ACLD treatment consists of a viscoelastic damping which is sandwiched between an active piezoelectric layer and a host structure. In this manner, the smart ACLD consists of a Passive Constrained Layer Damping(PCLD) which is augmented with an active control in response to the structural vibrations. The arc type shell model is introduced to describe the interactions between the vibrating host structure, piezoelectric actuator and viscoelastic damping. The system is modeled by applying ARMAX model and changing a state-space form through the system identification method. An optimum control law for the piezo actuator is obtain by LQR(Linear Quadratic Regulator) method. The performance of the ACLD system is determined and compared with PCLD in order to demonstrate the effectiveness of the ACLD treatment. Also, the actuation capability of a piezo actuator is examined experimentally by varying thickness of viscoelastic material(VEM).

• Smart Structures and Systems
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• v.22 no.1
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• pp.13-25
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• 2018

Pedro $G{\acute{o}}mez$ Bosque footbridge is a slender and lightweight structure that creates a pedestrian link over the Pisuerga River, Valladolid, Spain. This footbridge is a singular stress ribbon structure with one span of 85 m consisting on a steel plate and precast concrete slabs laying on it. Rubber pavement and a railing made of stainless steel and glass complete the footbridge. Because of its lively dynamics, prone to oscillate, a simple and affordable structural health monitoring system was installed in order to continuously evaluate its structural serviceability and to estimate its modal parameters. Once certain problems (conditioning and 3D orientation of the triaxial accelerometers) are overcome, the monitoring system is validated by comparison with a general purpose laboratory portable analyzer. Representative data is presented, including acceleration magnitudes and modal estimates. The evolution of these parameters has been analysed over one-year time.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.1032-1038
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• 2002

The Active Constrained Layer Damping(ACLO) combines the simplicity and reliability of passive damping with the low weight and high efficiency of active control to attain high damping characteristics. The proposed ACLD treatment consists of a viscoelastic damping which is sandwiched between an active piezoelectric layer and a host structure. In this manner, the smart ACLD consists of a Passive Constrained Layer Damping(PCLD) which is augmented with an active control in response to the structural vibrations. The Arc type shell model is introduced to describe the interactions between the vibrating host structure, piezoelectric actuator and visco damping, The system is modeled by applying ARMAX model and changing a state-space form through the system identification method. An optimum control law for piezo actuator is obtain by LQR(Linear Quadratic Regulator) Method. The performance of ACLD system is determined and compared with PCLD in order to demonstrate the effectiveness of the ACLD treatment, Also, the actuation capability of a piezo actuator is examined experimentally by using various thickness of Viscoelastic Materials(VEM).

• Structural Engineering and Mechanics
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• v.32 no.6
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• pp.787-809
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• 2009

Recent interest in the use of wireless sensor networks for structural health monitoring (SHM) is mainly due to their low implementation costs and potential to measure the responses of a structure at unprecedented spatial resolution. Approaches capable of detecting damage using distributed processing must be developed in parallel with this technology to significantly reduce the power consumption and communication bandwidth requirements of the sensor platforms. In this investigation, a damage detection system based on a distributed processing approach is proposed and experimentally validated using a wireless sensor network deployed on two laboratory structures. In this distributed approach, on-board processing capabilities of the wireless sensor are exploited to significantly reduce the communication load and power consumption. The Damage Location Assurance Criterion (DLAC) is used for localizing damage. Processing of the raw data is conducted at the sensor level, and a reduced data set is transmitted to the base station for decision-making. The results indicate that this distributed implementation can be used to successfully detect and localize regions of damage in a structure. To further support the experimental results obtained, the capabilities of the proposed system were tested through a series of numerical simulations with an expanded set of damage scenarios.