• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.8
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• pp.50-55
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• 2012

Grounding is very important for electrical safety. But it is very difficult to secure enough space for the installation and management of grounding in the city because of the congestion of the buildings. Therefore, to solve this problem, this paper suggest structure-grounding application taking advantage of building structure as protective grounding. And, to verify its feasibility, this paper shows the result to measure and analyze grounding-resistance of structure for 12 buildings mainly structed in the city.

• Structural Engineering and Mechanics
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• v.62 no.3
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• pp.303-310
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• 2017

The model updating problems, which are to find the optimal approximation to the discrete quadratic model obtained by the finite element method, are critically important to the vibration analysis. In this paper, the structured model updating problem is considered, where the coefficient matrices are required to be symmetric and positive semidefinite, represent the interconnectivity of elements in the physical configuration and minimize the dynamics equations, and furthermore, due to the physical feasibility, the physical parameters should be positive. To the best of our knowledge, the model updating problem involving all these constraints has not been proposed in the existed literature. In this paper, based on the semidefinite programming technique, we design a general-purpose numerical algorithm for solving the structured model updating problems with incomplete measured data and present some numerical results to demonstrate the effectiveness of our method.

• Smart Structures and Systems
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• v.22 no.1
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• pp.57-70
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• 2018

For the long-term structural health monitoring of civil structures, the effect of ambient temperature variation has been regarded as one of the critical issues. In this study, a principal component analysis (PCA)-based algorithm is proposed to filter out temperature effects on electromechanical impedance (EMI) monitoring of prestressed tendon anchorages. Firstly, the EMI monitoring via a piezoelectric interface device is described for prestress-loss detection in the tendon anchorage system. Secondly, the PCA-based temperature filtering algorithm tailored to the EMI monitoring of the prestressed tendon anchorage is outlined. The proposed algorithm utilizes the damage-sensitive features obtained from sub-ranges of the EMI data to establish the PCA-based filter model. Finally, the feasibility of the PCA-based algorithm is experimentally evaluated by distinguishing temperature changes from prestress-loss events in a prestressed concrete girder. The accuracy of the prestress-loss detection results is discussed with respect to the EMI features before and after the temperature filtering.

• Journal of Pharmaceutical Investigation
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• v.35 no.4
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• pp.243-247
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• 2005

Although many scientists have used pectin, its feasibility in terms of tablet manufacturability with a high speed machine has never been evaluated. Therefore, compactibility of different pectin types for large scale tableting operation has been evaluated. The compactibility behavior of powder pectins was studied by a compaction simulator. It was found that pectin on its own does not produce tablets of acceptable quality even at a punch velocity as low as 20 rpm (e.g. low tensile strengths, capping and lamination irrespective of applied compression force). Thus, dwell time was introduced and more hard compact was produced as relaxation time in die increases. It was concluded that frequent structural failure observed in both pectin types was due to lack of plastic deformation, poor compactibility and high elastic recovery.

• Structural Engineering and Mechanics
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• v.16 no.1
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• pp.101-114
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• 2003

A base isolation system is proposed for earthquake protection of structures. The system incorporates spherical supports for the base, a specially designed spring-cam system to keep the base rigidly supported under normal condition and to allow it to move for the duration of the earthquake under the constraint of a spring with optimized non-linear characteristics. A single-story model is constructed to investigate the feasibility of the concept. Numerical simulations of the system as well as experimental results show that 95% reduction of the transmitted force to the structure can be achieved. To demonstrate the effectiveness of this isolation mechanism, the maximum dynamic bending stress developed at predetermined critical points within the frame of the structure is measured. Significant reduction of the dynamic stresses is obtained.

• Structural Engineering and Mechanics
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• v.37 no.5
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• pp.561-573
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• 2011

For efficient calculation of natural modes of structures, a numerical scheme which accelerates convergence of the subspace iteration method by employing accelerated starting Lanczos vectors was proposed in 2005. This paper is an extension of the study. The previous study simply showed feasibility of the proposed method by analyzing structures with smaller degrees of freedom. While, the present study verifies efficiency of the proposed method more rigorously by comparing closeness of conventional and accelerated starting vectors to genuine eigenvectors. This study also analyzes an example structure with larger degrees of freedom and more complex constraints in order to investigate applicability of the proposed method.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.255-255
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• 2006

Polymeric nanoparticles are recognized as promising drug carriers [1]. Here, novel tri-block copolymers based on poly PPDO, PCL and PEG were synthesized and employed for the formulation of reproducible polymeric nanoparticles [2]. To estimate the feasibility of the polymer to form polymeric nanoparticles, nanoparticles were prepared by co-solvent evaporation technique. Polymerization and structural features of the polymer were analyzed by different physico-chemical techniques. Existence of hydrophobic domains as a core of nanoparticles was characterized by $^{1}H-NMR$ spectroscopy, and further confirmed by fluorescence technique using pyrene as probe.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2011.05b
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• pp.133-136
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• 2011

This study concerned with the steel beam of bonding method and bonded steel beams by this method and both ends of different height, steel beams and steel beams in the center makes the junction. Both ends and the central part of steel beams connecting the lower flange by additional combining steel plates to convey stress, the stress to focus on the beam connections are passed to both ends of steel beams, and strength of beam connections is improved and steel structural beams is proposed to minimize the loss by Incision. If you use the developed method, the construction period is shortened, and reducing the amount of material can decrease the cost and reduction in floor height can be maximized business feasibility.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2011.05b
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• pp.81-83
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• 2011

A modular house is a house that is assembled on-site from modularized units. As such units are manufactured in a factory, the construction period is reduced, resources are recycled, and quality is improved. However, the construction technique applied to conventional modular houses has not overcome certain structural restrictions, as it is currently used to build houses less than 4 stories in height, which means that it lacks economic feasibility. For this reason, this research aims to develop a scenario of a construction method for Korean modular housing that can be applied to urban-type housing higher than 12 stories. This research is expected to provide fundamental data necessary for the future development of a construction method for Korean modular housing.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.13 no.2
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• pp.85-93
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• 1993

Base isolation systems are economic and efficient for the control of structural vibration. In this study, the base isolators of LRB(laminated rubber bearing) type which have been generally used are fabricated and tested. From the static and dynamic tests, the characteristics of the base isolators, considering strain-hardening, hysteretic damping and horizontal stiffnesses, etc., are verified and particularly the feasibility as base isolation devices is discussed. Consequently, the test results are compared with the analytical ones that are derived from idealization as a bilinear model.