• Proceedings of the Korea Contents Association Conference
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• 2011.05a
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• pp.493-494
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• 2011

국내에서의 NTIS의 높은 인지도와 달리 해외에서 세계 최초의 국가R&D정보 종합포털로서의 NTIS의 인지도는 전무한 현실이다. 한국과학기술정보연구원에서는 2010년도부터 이러한 문제를 인식하여 NTIS 브랜드의 국제화 및 국내 외 홍보강화를 통해 국내 외 협업 공동연구 활성화를 촉진하고 이를 통한 고부가가치 연구성과의 창출 확산을 위하여 NTIS 영문포털 서비스를 개발하여 서비스 중이다. NTIS에서 제공 중인 주요 서비스에 대한 소개, 과제, 연구자 영문이력정보, 및 영문초록 정보 등 다양한 정보를 제공하고 있으며 2011년도에는 EU의 CORDIS, 미국의 NSF등과의 연계체계 구축을 통해 국내 연구자들에게 주요국의 R&D정보를 제공할 예정이다. 본 논문에서는 NTIS 영문포털의 개요 및 향후 발전방향에 대하여 논하고자 한다.

• Journal of the Earthquake Engineering Society of Korea
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• v.9 no.3 s.43
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• pp.59-68
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• 2005

The energy-based seismic design method Is more rational in comparison with current seismic design code in that it can directly account for the effects of cumulative damage by earthquake and hysteretic behavior of the structure. However there are research results that don't reach a consensus depending on the ground motion characteristic and structural properties. For that reason in this study the influences of ground motion characteristics and structural properties on energy demands were evaluated using 100 earthquake ground motions recorded in different soil conditions, and the results obtained were compared with those of previous works. Results show that ductility ratios and sue conditions have significant influence on input energy. The results show that the ratio of hysteretic to input energy is considerably influenced by the ductility ratio, damping ratio, and strong motion duration, while the effect of site condition is insignificant.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.05a
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• pp.172-172
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• 2004

형상기억합금 작동기는 스마트 작동기의 대표주자로서 부피 대비 발생력이 다른 어느 재료보다 우수하고, 모터와 같은 작동소음이 발생하지 않으며, 온도변화에 의한 간단한 작동원리로 근래에 많은 연구자들의 관심을 받아왔다 그러나, 온도변화 대 변위 곡선을 살펴보게 되면 이력곡선, 포화현상 등의 강한 비선형성을 내제하고 있고, 대류조건에 따른 온도외란에 민감하다. 이로 말미암아 정밀한 위치제어에 상당한 문제를 수반하고 있으며, 기존의 PID제어기나, 모델기저 제어기를 사용하게 될 경우 정상 상태오차와 한계싸이클 등의 현상이 나타나는 것으로 문헌에 보고되고 있다.(중략)

• Journal of the Korea Concrete Institute
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• v.15 no.5
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• pp.662-669
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• 2003

Recently, the serviceability and durability of concrete structures under thermal load have received great attention. The thermal stress and clacking behavior of concrete at early ages are one of the important factors that affect such serviceability and durability of concrete structures. Nevertheless, most studies on the behavior of early-age concrete have been confined to the temperature and strain development itself in the laboratory. The desirable efforts to explore the material properties of concrete at early-ages have not been made extensively so far. The purpose of the present study is, therefore, to identify some important material properties that affect the stress behavior of concrete at early-ages. To this end, full-scale concrete base-restrained wall members have been fabricated, and many sensors including thermocouples, strain meters and stress meters were installed inside of the wall members. These sensors were to measure the development of temperatures, strains and stresses at several location in concrete walls during the hardening and curing phase of early-age concrete. By using these measured values of strain and stress, the compliance function at early-age was identified. The basic form of compliance function derived in this study follows the double-power law. However, the results of present study indicate that the values of existing compliance functions are much lower than actual values, especially at very early-ages. It can be seen that the prediction of stresses of early-age concrete based on the proposed compliance function agrees very well with test data. The present study allows more realistic evaluation of varying stresses in early-age concrete under thermal load.

• Journal of the Earthquake Engineering Society of Korea
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• v.3 no.1
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• pp.55-66
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• 1999

This paper presents an analytical prediction of the hysteresis behavior of reinforced concrete long column with rectangular section under the cyclic loading state. The mechanical characteristic of cracked concrete and reinforcing bar in concrete has been modeled, considering the bond effect between reinforcing bar and concrete, the effect of aggregate interlocking at crack surface and the stiffness degradation after the crack has taken place. The strength increase of concrete due to the lateral confining reinforcement has been also taken into account to model the confined concrete. The formulation of these models for concrete and reinforcing bar has been based on the smeared crack concept that the stress-strain relationship of reinforced concrete element would be defined using the average values. In addition to the material nonlinear properties, the algorithm for large displacement problem that may give an additional deformation has been formulated using total Lagrangian formulation. The analytically predicted behavior was compared with test result and they showed good agreement in overall behavior.

• Journal of the Earthquake Engineering Society of Korea
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• v.7 no.3
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• pp.31-38
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• 2003

Lap splices were located in the plastic hinge region of most bridge piers that were constructed before the adoption of the seismic design provision of Korea Highway Design Specification on 1992. But sudden brittle failure of lap splices may occur under inelastic cyclic loading. The purpose of this study is to analytically predict nonlinear hysteretic behavior and ductility capacity of reinforced concrete bridge piers with lap splices under cyclic loading. For this purpose, a nonlinear analysis program, RCAHEST(Reinforced Concrete Analysis in Higher Evaluation System Technology) is used. Lap spliced bar element is developed to predict behaviors of lap spliced bar. Maximum bar stress and slip of lap spliced bar is also considered, The proposed numerical method for seismic performance evaluation of reinforced concrete bridge piers with lap splices is verified by comparison with reliable experimental results.

• Polymer(Korea)
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• v.28 no.6
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• pp.455-459
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• 2004

Ionic conductivities of poly(ethylene oxide) (PEO)-based electrolytes are in a considerable inconsistency in many papers, varying more than three orders of magnitude for just same compositions. In PEO-salt-ceramic composite electrolytes, it has been also reported that the conductivity can be variant by almost three orders of magnitude according to thermal treatment and it has been regarded as a consequence of polymer-ceramic particle interaction. In this paper, we present a more systematic study on the change of ionic conductivity for ceramic-free PEO$_{10}$LiClO$_4$ polymer electrolytes, and found that the ionic conductivity can be variant more than hundred times according to thermal history. The slow recrystallization kinetics of PEO polymer is discussed to be responsible for the thermal history effect. Present results reveal that the effect of ceramic filler is not a main cause of the conductivity relaxation phenomenon.n.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.13 no.2
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• pp.189-196
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• 2000

The objective of this paper is to propose an analysis technique to predict the behavior of PC wall structures subjected to cyclic load. While PC wall panel is idealized by finite elements, the joints at which PC walls are connected each other are idealized by nonlinear spring elements. Axial and shear spring elements are developed for simulating shear, compression and tension behaviors of joints. The strength and stiffness of each spring elements we presented from the previous research results and incorporated into the computer program of DRAIN-2DX. The proposed analysis technique is evaluated by analyzing specimens previously tested and comparing with those. On the strength, stiffness, energy dissipation and lateral drift, analytical results show good agreements with test results. This means the proposed technique is effective to predict the response of the PC wall structures.

• Journal of the Earthquake Engineering Society of Korea
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• v.8 no.1
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• pp.39-58
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• 2004

It is very important that predict the inelastic seismic behavior exactly for seismic performance evaluation of a building in the performance based seismic design. Evaluation method of seismic performance based on the pushover analysis reflected in PBSE was developed by some researchers. For the evaluation of inelastic global and local seismic responses by pushover analysis exactly. lateral load distribution should be adjusted and reflected the dynamic characteristics of structural system and various seismic ground motions. And performance point should be determined based on the evaluation of reasonable deformation capacity of a building more exactly. An effective method based on the improved the adaptive lateral load distribution and the equivalent responses of a multistory building is proposed in this study to efficiently estimate the accurate inelastic seismic responses. The proposed method can be used to evaluate the seismic performance for the global inelastic behavior of a building and to accurately estimate its local inelastic seismic responses. In order to demonstrate the accuracy and validity of this method, inelastic seismic responses estimated by the proposed method are compared with those obtained from other analytical methods.

• Journal of the Earthquake Engineering Society of Korea
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• v.1 no.4
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• pp.1-9
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• 1997

This paper examined various aspects of a linear and a nonlinear response spectrum method in seismic response analysis of multi-story building structures. The response spectrum method that has been widely used in the analysis of linear structures was proposed different mode superposition method by several ivestigators, and the differences between combinations with an elastic modal analysis reviwed closely. It seems, however, that this method is not used to nonlinear seismic analysis. It is the purpose of this paper to propose an alternative method by means of which a nonlinear MDOF structure with long period may be analysed by an extention of response spectrum method. For nonlinear seismic analysis of high-rise building structures using technique proposed in this study, it is intended to serve primarily as a tool in preliminary designs instead of time history analysis.