• Journal of the Korea institute for structural maintenance and inspection
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• v.14 no.1
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• pp.148-155
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• 2010

The purpose of this study is to propose and evaluate the continuous joint constructed with MRS system which is utilized for floor system in the parking structures or commercial retail buildings. Four specimens were fabricated and tested to examine the structural performance of the continuous joint with different joint detailing. Structural test for the specimens was undertaken to simulate the actual stress condition of the negative moment resisting connection in the prestressed precast concrete parking structures with 8m span. Based on the experimental results, the MRS system could be designed as the ductile continuous joint governed by flexural behavior. Therefore the MRS system developed in this study would provide a superior joint behavior to conventional double-tee system when constructing monolithic joint composed of simply supported precast members.

• Journal of the Korea Concrete Institute
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• v.22 no.2
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• pp.247-254
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• 2010

The purpose of study is to investigate the load resistance mechanism of MRS continuous joint designed with different details. Six full-scale specimens, which could simulate the negative moment region of the 8 m long MRS system, were prepared to evaluate the structural performance of the continuous joint. According to the experimental results, all specimens which include the specimen with dapped ends designed by loads at the construction stage were failed in a flexural manner and showed the load carrying capacity over the nominal flexural strength. Therefore it is recommended that the dapped ends for MRS continuous joints be designed for the loads of the construction stage. And the shear key, which was installed on the top of rib for MRS slab, helps the enhancement of strength and especially deformation capacity.

• Journal of the Korea Concrete Institute
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• v.23 no.2
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• pp.177-184
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• 2011

This paper describes an analytical study on the design approach of PC system with continuous connections at member ends. In multi-ribbed moment resisting slab (MRS) system, double tee members are connected continuously over inverted tee beams with the continuous reinforcements placed within topping concrete. Thus, negative moments are concentrated within the narrow connection area. In order to propose a design method, experimental results of the companion study were examined using detailed nonlinear analysis. Then nonlinear static analysis was used to evaluate the partial continuity effect and the moment redistribution mechanism. Material and cross sectional properties were obtained from experimental results of the companion study. Plastic hinge properties for nonlinear static analysis were modeled with cracking moment, nominal moment, corresponding member deformations, etc. The analysis results showed that a large amount of negative moment of MRS slab can be reduced by applying partial continuity and moment redistribution in MRS joint.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.9
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• pp.4326-4341
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• 2016

In this paper, an adjustable multiple relay selection (MRS) scheme for cooperative communication with amplify-and-forward (AF) relay under frequency selective channels is proposed. In the proposed scheme, the relays are ordered firstly by the steady-state mean square error (MSE), then the relays are sequentially selected out from N relays and the number of cooperating relays is adjusted dynamically according to the steady-state mean square joint error (MSJE). The aim of this work is to dynamically estimate the optimum number N_o of cooperating relays. Optimum means the minimum number of cooperating relays, N_o, achieving the minimum level of steady-state MSJE. Numerical results verify the analyses and show that the scheme can adaptively adjust the number of cooperating relays, and outperform conventional relay selection schemes. Hence, the proposed scheme provides better tradeoff between BER performance and spectral efficiency and to save more energy in cooperative wireless networks.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.41 no.3
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• pp.17-24
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• 2004

We present a P-type iterative learning control(ILC) scheme for uncertain robotic systems that perform the same tasks repetitively. The proposed ILC scheme comprises a linear feedback controller consisting of position error, and a feedforward and feedback teaming controller updated by current velocity error. As the learning iteration proceeds, the joint position and velocity mrs converge uniformly to zero. By adopting the learning gain dependent on the iteration number, we present joint position and velocity error bounds which converge at the arbitrarily tuned rate, and the joint position and velocity errors converge to zero in the iteration domain within the adopted error bounds. In contrast to other existing P-type ILC schemes, the proposed ILC scheme enables analysis and tuning of the convergence rate in the iteration domain by designing properly the learning gain.