• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.53-56
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• 2008

Reinforced concrete rahmen structures has been required ductility as well as strength of beam-column joint in seismically hazard area. Some investigations have been presented for retrofitting and/or strengthening structural elements in structure. Strain-hardening cementitious composite(SHCC) has been expected excellent reinforcement performance in beam-column joint area. The properties of reinforcing fiber, as tensile strength, aspect ratio and elastic moudulus, have great effect on the fracture behavior of SHCC. The purpose of this experimental study is to evaluate structural performance of exterior reinforced concrete beam-column joint strengthened with SHCC under cyclic loading.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.12 no.4_1
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• pp.23-32
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• 1992

The objective of this study is to identify the quantitative relationships among the important physical factors associated with failure of steel members under strong seismic excitations through very low-cycle fatigue tests. Very low-cycle fatigue is meant to be structural fatigue causing cracks and rupture in about 5~30 cycle ranges. The angle specimen was subjected to repeated axial Ioad after undergoing inelastic buckling. The test results reveal that the energy absorption capacities vary heavily with the history of loading and the failure mode. The maximum values of residual local strain at the initiation of a visible crack due to the very low-cycle fatigue were of the order of 25~40%, regardless of loading patterns, deflection modes, and width-to-thickness ratios.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2003.11a
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• pp.59-62
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• 2003

Kinds, shapes and fraction ratios of fibers have influence on properties of HPFRCC(High-Performance Fiver Reinforced Cementitious Concrete) like bending strength, strain capacity and fracture toughness. For example, hydrophilic fibers have different chemical bond strength from hydrophobic fibers, fiber shapes influence on fiber pull-out and rupture, and fiber volume fraction influence on bending strength. In this study, to estimate influences of kinds, shapes and fraction ratios of fibers, we make HFRCC with 3 kind of fiber in various volume fraction of fiber and compare cracking, bending strength and fracture toughness. As the results, bending strength of HPFRCC was increased as fiber volume fraction was increase and fiber tensile strength was increase, and strain capacity and fracture toughness of HFRCC was higher in fiber pull-out fracture than in fiber rupture fracture. And HFRCC showing pseudo strain hardening has higher fiber reinforce efficiency than others.

• Composites Research
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• v.24 no.3
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• pp.25-30
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• 2011

The studies on the non-destructive testing methods of the composite materials are very important for improving their reliability and safety. AE(Acoustic Emission) can evaluate the defects by detecting the emitting strain energy when elastic waves are generated by the generation and growth of a crack, plastic deformation, fiber breakage, matrix cleavage or delamination. In this paper, the AE signals of the filament wound composite cylinder and sandwich cylinder during the pressure test were measured and analyzed. The signal characteristics of PVDF sensors were measured, and an AE signal analyzer which had the band-pass filter and L-C resonance filter were designed and fabricated. Also, the crack detection capability of the fabricated AE signal analyzer wes evaluated during the pressure tests of the filament wound composite cylinder and the sandwich cylinder.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.10a
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• pp.479-482
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• 2001

IDS has been studied mainly in the field of the detection decision and collecting of audit data. The detection decision should decide whether successive behaviors are intrusions or not, the collecting of audit data needs ability that collects precisely data for intrusion decision. Artificial methods such as rule based system and neural network are recently introduced in order to solve this problem. However, these methods have simple host structures and defects that can't detect transformed intrusion patterns. So, we propose the method using data mining that can retrieve and estimate the patterns and retrieval of user's behavior in the distributed different hosts.

• Journal of the Korea Society of Computer and Information
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• v.10 no.3 s.35
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• pp.183-188
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• 2005

Parallel processing in block cryptographic algorithm is difficult, because Feistel structure that is basis structure of block cryptographic algorithm is sequential processing structure. Therefore this paper changes these sequential processing structure and Feistel structure made parallel processing to be possible. This paper that apply this modified structure designed DES that have parallel Feistel structure. Proposed parallel Feistel structure could prove greatly block cryptographic algorithm's performance such as DES and so on that could not but have trade-off relation the data processing speed and data security interval because block cryptographic algorithm can not use pipeline method because of itself structural problem. Therefore, modified Feistel structure is going to display more superior security function and processing ability of high speed than now in case apply way that is proposed to SEED, AES's Rijndael, Twofish etc. that apply Feistel structure.

• Journal of the Korea institute for structural maintenance and inspection
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• v.14 no.5
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• pp.161-168
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• 2010

Practicing engineers and researchers need computational tools that estimate accurately the cyclic response of RC walls, and in particular, force and deformation capacities and their materials strains. So this paper describes a nonlinear truss modeling approach for reinforced concrete walls, or in general, for plane stress reinforced concrete elements subjected to cyclic reversals. Nonlinear vertical, horizontal, and diagonal truss elements are used to represent concrete and steel reinforcement. The wall having aspect ratio of 1.2 was chosen to be compared with the experimental results. Here, four types of main diagonal member models and three types of diagonal members models were applied to find out more accurate results of analysis.

• The Journal of the Korean bone and joint tumor society
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• v.17 no.1
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• pp.11-16
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• 2011

Purpose: This study was aimed to analyze the incidence and the anatomical distributions of HME (Hereditary Multiple Exostoses) on upper limbs and its related change in alignment of the upper limbs in HME patients. Materials and Methods: Thirty eight patients who had been diagnosed HME between 2001 and 2009, were categorized into two groups; (1) group A (1-2 involvements); (2) group B (${\geq}$3 involvements). We checked the carrying angle, VAS (Visual Analogue Scale), limitations in daily activities, cosmetic satisfaction according to the number of exostoses invasion. Results: Among the 38 patients, 23 patients (43 cases) had exostoses in the upper limbs. The locations of exostoses in the upper limbs were proximal humerus in 33 cases (30%), distal ulna in 31 cases (28.2%), and distal radius in 24 cases (21.8%). The carrying angle of group A and B was $10.7^{\circ}$, $13.8^{\circ}$, VAS was 1.3, 3.5, and the limitations in daily activities was 7.3, 6.6 of 8 points. The cosmetic satisfactory cases were 13 and 10 cases, respectively. Conclusion: The deformity in upper limbs was observed in 65% of the HME patients. As the number of invasion increases, carrying angle and VAS were increased but limitations in daily activities and cosmetic satisfaction were decreased.

• Journal of the Korean Society for Library and Information Science
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• v.25
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• pp.295-324
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• 1993

최근 정보기술의 급속한 발달 따라 사회 전반적인 체제의 정보화 현상으로 개인이나 조직의 활동이 정보와 밀접한 관련성을 가지게 됨으로써 이용자의 정보 수요에 적합한 정보원을 제공하는 매개자의 기능을 수행하고 있는 정보전문가의 역할이 한층 더 부각되고 있다. 이러한 영향이 도서관이나 정보센터의 모든 활동에 파급됨에 따라 정보를 수집, 가공, 분석. 저장 및 전달을 담당하고 있는 정보 전문가는 종래의 문헌중심봉사(book-based service)에서 정보중심봉사(information-based service) 형태로 역할 변환이 요구되고 있다. 특히 주제전문 봉사를 담당하고 있는 사서나 정보전문가는 이러한 정보기술의 파급효과를 더욱 실감하고 있는 실정이다. 이러한 상황에서 본 연구는 첫째, 정보기술의 발달이 사회과학 분야의 정보봉사에 미치는 영향과 효과를 살펴보고. 둘째로 사회과학 분야 정보제공을 위한 정보시스템의 특성 분석과 정보기술을 매체로 이용하고 있는 정보전문가의 정보기술에 대한 인식을 실증적으로 분석하고 있으며, 마지막으로 정보사회에서 다양한 정보제공을 담당할 사회과학 정보전문가의 새로운 역할 모델을 제시하고 있다. 사회과학 분야의 정보제공을 효율적으로 수행하기 위한 정보시스템의 구축은 학제적 성을 지니고 있는 사회과학 전반에 대한 이해와 특성을 파악함으로써 가능하다. 사회과학의 연구대상은 인간 상호작용에 관한 지식의 전반적인 분야를 포괄하고 있어 많은 주제분야가 서로 중복되거나 상호 호환적인 성격을 지니고 있기에. 사회과학 정보시스템이 이용자의 정보요구에 만족을 주기 위해서는 이용자의 유형, 정보요구의 형태 및 그 해결방안에 일차적 관심을 가져야한다. 사회과학 분야의 정보유통 체제를 살펴보면, 대부분 통계자료나 단편적인 데이타로 시작되는 원자료가 사회과학자나 연구자에 의해 "지적 변환(intellectual transformation)" 과정을 거쳐 논문이나 저서 등과 같은 정형화된 문헌의 형태로 나타나게 된다. 정형화된 문헌이 다른 이용자의 요구에 효율적으로 이용되기 위하여 다시 "서지적 변형(bibliographic transformation)" 과정이 수반됨으로써 도서관이나 정보센터의 정보시스템에서 문헌검색이 가능하게 된다. 정보기술의 발달과 보급 이전에는 서지적 변형 단계에서 대부분 정보제공시스템의 역할이 종결되었으나, 최근 정보기술의 활용으로 서지적 변형 후 각종 정보자료의 색인과 초록 및 네트웍 화를 통한 자동화 과정이 이루어짐으로써 이용자의 정보요구에 최대의 만족을 제공할 수 있는 정보자료의 체계적인 분석과 효율적인 통제로 포괄적인 정보관리 차원으로 이전되고 있음을 알 수 있다. 사회과학 분야를 담당하고 있는 사서를 대상으로 실시한 설문조사에서 새로운 정보기술의 활용에 따른 정보전문가의 인지적 혹은 업무 적 변화가 매우 긍정적인 방향으로 뚜렷이 나타나고 있음을 알 수 있다. 정보기술을 이용하고 있는 대부분의 사서들은 정보기술이 그들의 정보봉사 업무를 쉽게, 빠르게. 그리고 정확하게 처리하고 있으며, 새로운 정보기술 습득에 호의적인 반응을 보이고 있다. 아울러 정보기술의 이용에 따른 추가적인 책임이나 의무가 수반되고 있는 것으로 나타나고 있으며, 정보기술이 정보전문가의 역할을 완전히 대체할 정도로 위협을 느끼고 있지는 않는 것으로 조사되고 있다. 종합적인 반응은 대부분의 사서들이 정보 봉사 업무에 정보기술의 활용을 매우 바람직한 것으로 보고 있으며. 이용자 요구를 극대화하기 위한 정보관리에 필수불가결 한 도구로 인식하고 있다. 과거의 유능한 사서나 정보전문가는 자관의 정보원에 대한 철저한 이해로 이용자의 요구에 봉사하는 것으로 간주되었으나, 현재 그리고 미래의 유능한 정보전문가는 자관은 물론 국가적 혹은 세계적인 정보원에 접근할 수 있는 정보원 관리 능력은 물론 정보기술의 활용과 이용자에 대한 교육적 능력을 동시에 지녀야 할 것으로 여겨진다. 이러한 관점에서 사회과학 분야의 정보제공을 담당하고 있는 정보전문가의 새로운 역할을 크게 이용자 보조 역할, 주제전문가 역할. 시스템 전문가 역할, 그리고 정보원 관리자 역할로 구분할 수 있다.

• Journal of the Korea Concrete Institute
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• v.28 no.5
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• pp.563-570
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• 2016

The composited structural member in which two or more materials having different stress-strain relationships (steel & concrete) has increased greatly in recent years. This paper presents the experimental results of flexural capacity of the composited H-Pile subjected to bending moment. Eight composited beams were tested under direct loading condition using the frame tester. Based on the experimental results it is noted that flexural capacity of composited H-Pile increased about 20~30% and ductility ratio significantly increased. Limit state analysis of the specimens was conducted and the result shows that flexural strength by limit state analysis is conservative.