• Journal of the Korea Concrete Institute
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• v.12 no.4
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• pp.3-14
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• 2000

Structural performance of the walls subjected to lateral load reversals depends on various parameters such as loading history, sectional shape, reinforcement, lateral confinement, aspect ratio, axial compression, etc. Thus, the performance of the shearwall for wall-type apartment should be evaluated properly considering above parameters. This study investigates the effect of sectional shape on the structural performance of the wall. Sectional shape of the specimen is rectangular, barbell and T. Based on this experimental results, all specimens behaved as ductile fashion and failed by concrete crushing of the compression zone. Deformation index of those specimens evaluated better than 3 of ductility ratio, and 1.5% of deformability specified by seismic provision. Moreover, the performance of the rectangular shaped specimen, whose compression zone was confined with U-bar and cross tie, was as good as the barbell shaped specimen. Therefore, if we considered construction practice such as workmanship and detailing, shearwall with rectangular section may be more economical lateral load resisting system.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1999.10a
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• pp.214-224
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• 1999

The design response spectrum has been widely used in seismic design to estimate force and deformation demands of structures imposed by Earthquake Ground Motion (EQGM). Inelastic Design Response Spectra (IDRS) to specify design yielding strength in seismic codes are obtained by reducing the ordinates of Linear Elastic Design Response Spectrum (LEDRS) by strength reduction factor (R). Since a building is designed using reduced design spectrum (IDRS) rather than LEDRS in current seismic design procedures it allows structures behave inelastically during design level EQGM. Inelastic Response Spectra (IRS) depend not only on the characteristics of the expected ground motion at a given site, but also on the dynamic properties and nonlinear characteristics of a structure. However, it has not been explicitly investigated the effect of different hysteretic models on IRS. In this study, the effect of hysteretic models on IRS is investigated.

• Journal of Ocean Engineering and Technology
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• v.7 no.1
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• pp.33-55
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• 1993

선수충격파의 문제를 푸는데 있어서 Boundary Integral Method(BIM)의 여러가지 수치 해석방법이 검토되었으며, 특히 여러가지 Time stepping scheme, Green function, far-field 조건등에 따른 수치해석안정성과 정확성의 상관관계가 연구되었다. von Neumann 안정성해석과 matrix 안정성해석 등을 이용한 선형 안정성해석을 기초로하여, 수치해석방법의 안정성 여부를 체계적으로 조사할 수 있는 parameter(Free Surface Stability number)를 설정하고, 이 parameter의 변화에 따른 비선형 운동해석을 연구하였다. 그 결과 비선형성이 심하지 않은 기진파의 경우에서는 비선형 운동해석의 수치해석 안정성의 선형 수치해석 안정성과 큰 차이가 없음을 알 수 있게 된다.

• 보존과학연구
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• s.28
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• pp.149-168
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• 2007

This project aims to develop a partnership between France and Korea; the field of paper conservation with two mains objectives. The first object is to study the possibilities of implementing the use of traditional Korean paper in conservation workshops in France and Europe. The second one is to establish a long term collaborative research program to investigate the degradation mechanisms of ancient papers and particularly early waxed manuscripts founded in Korea and France which are now brittle and fallen into parts. This problem deserves an investigation using analytical tools such as SEC/MALS, GC/MS to understand the interactions between wax and cellulose during the ageing process and to recommend proper conservation treatment. A research plan could be establish for both institution in order to facilities an exchange of visiting scholars (scientist, post-doc) to implement and share knowledge and for carrying out the research.

• The KIPS Transactions:PartC
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• v.12C no.2 s.98
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• pp.229-234
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• 2005

We propose a fuzzy logic-based buffer management algorithm to improve internet traffic over ATM-GFR service. The proposed algorithm employs the strategies of early congestion detection and selective packet discard to achieve its design goals. A key feature of proposed algorithm is its ability to accept or drop a new incoming packet dynamically based on buffer condition and load rate of VCs. This is achieved by using fuzzy logic controller for the production of a drop factor. Simulation results show that proposed scheme significantly has improved fairness and TCP throughput compared with previous schemes.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1634-1635
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• 2007

본 논문은 갠트리 크레인의 시뮬레이터를 제작하여 적응형 흔들림 제어기를 설계한다. 흔들림 감지는 디지털 카메라 센서를 이용하였으며 모델기반 적응제어를 이용하여 제어규칙을 산출한다. 제어규칙은 리아푸노브 안정성이론을 적용하였으며 정의된 리아푸노브 함수의 미분식이 음수를 갖기 위한 크레인의 적응형 제어입력을 계산한다. 제안한 제어기의 성능을 검토하기 위하여 실시간 제어실험을 실시하였으며 이송체의 무게 변화에 대한 적응성을 검토한다. 또한 기존의 PI 제어기도 함께 실험하여 성능의 비교 검토한다.

• International Journal of Advanced Culture Technology
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• v.10 no.1
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• pp.196-203
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• 2022

Developing smart cities increasingly relies on metaverse technology. This has become much more apparent in the post-COVID-19 pandemic urban environment. The demand for fast processing of huge amounts of data and the convergence of various media types is essential for keeping city residents well-informed and safe. This paper builds on recent research on metaverse, smart cities, and digital outdoor advertising media. It proposes that "space culture media", which collectively functions by using physical or virtual spatial information, will play a key role in the smart city, functioning as an augmented city. Specifically, this paper deals with significant issues related to the smart city changes created by tecoration, a metaverse urban media space facilitated and enhanced through digital outdoor advertising.

• Journal of Information Management
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• v.43 no.4
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• pp.143-167
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• 2012

In this study, survey analysis was conducted to determine the demands of science & technology information service by the groups of users. The questionnaire was composed of the need for 20 services in the science & technology information, the need for personal information to people-to-people exchanges, and information that can be shared with others. KOSEN users 1,013 people participated in the survey, and the analysis of variance was conducted depending on institution, profession, final degree and the age of the respondents. Results of frequency analysis, there were in high demands for trend analysis, papers, research reports, patents, knowledge queries, project announcements, jobs, experimental methods, information society and study abroad/Post-doc information, and all services except mentoring, community and blog were appeared to have the significant differences depending on the groups of users. Also the personal information deemed to be necessary for interaction with others was resulted in specialization, thesis/research performances, career, organization, jobs, final degree and education in order, there were partially difference depending on the user's groups. In addition, 97% of respondents had their own scientific and technical information to be shared with other people in order of papers, presentations (ppt), reports, experimental methods and the images. The results of this study can be used as useful information for scientists and engineers to develop a user-centered personalized services and are expected to be helpful to set the direction of science information services in the future.

• Tunnel and Underground Space
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• v.31 no.1
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• pp.41-51
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• 2021

The hydraulic fracturing developed to improve permeability of tight reservoir is one of key stimulation technologies for developing unconventional resources such as shale gas and deep geothermal energy. The experimental study was conducted to improve disadvantage of hydraulic fracturing which has simple fracture pattern and poor fracturing efficiency. The fracturing experiments was conducted for tight rock using various fracturing fluids, water, N2, and CO2 and the created fracture pattern and fracturing efficiency was analyzed depending on fracturing fluids. The borehole pressure increased rapidly and then made fractures for hydraulic fracturing with constant injection rate, however, gas fracturing shows slowly increased pressure and less fracture pressure. The 3D tomography technic was used to generate images of induced fracture using hydraulic and gas fracturing. The stimulated reservoir volume (SRV) was estimated increment of 5.71% (water), 12.72% (N2), and 43.82% (CO2) respectively compared to initial pore volume. In addition, permeability measurement was carried out before and after fracturing experiments and the enhanced permeability by gas fracturing showed higher than hydraulic fracturing. The fracture conductivity was measured by increasing confining stress to consider newly creating fracture and closing induced fracture right after fracturing. When the confining stress was increased from 2MPa to 10MPa, the initial permeability was decreased by 89% (N2) and 50% (CO2) respectively. This study shows that the gas fracturing makes more permeability enhancement and less reduction of induced fracture conductivity than hydraulic fracturing.

• Journal of Korean Library and Information Science Society
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• v.35 no.4
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• pp.423-449
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• 2004

In the knowledge society the main resource is knowledge, and the role of library to manage knowledge and information is very important. Therefore it is necessary to knowledge and information management that provides on demand service to user. The purpose of this research is to design model for web-based help-desk knowledge management system. This study used Qualitative methods as interviews and surveys through BBS and e-mail on information service in the university libraries. Here the investigated component factors are followings Q/A service user's education service to use the library, user's online reference service, e-mail service, FAQ service electronic service(BBS), lecture and research service for faculty, my library, SDI service, and open data service. This study was financially supported by Chonnam National University in the program, Post-Doc. 2002.