• Structural Engineering and Mechanics
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• 제6권7호
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• pp.747-756
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• 1998

In this paper the influence of rotary inertia, shear and compressibility on the value of the critical force for the Beck's column is analyzed. The constitutive equation is of Engesser's type. As a result, the critical load parameter for which instability of flutter type occurs is calculated for several values of the column's parameters.

• 한국섬유공학회:학술대회논문집
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• 한국섬유공학회 1998년도 가을 학술발표회논문집
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• pp.394-397
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• 1998

Characteristics of air-jet textured yarns are determined by linear density, strength, and instability together with structural properties. Such characteristics are affected by various processing parameters and supply yam properties. In this Paper, specially, we have studied on the effect of air jet texturing conditions not only on texturing characteristics but also on splitting behavior using split-type ultrafine P/N filaments and their draw textured yarns as raw materials. (omitted)

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 1998년도 추계 학술발표회 논문집 Proceedings of EESK Conference-Spring 1998
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• pp.93-99
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• 1998

Mathematical model can be obtained by physical law or engineering theory. However it is always incomplete expression of the real system. In active controls to suppress vibration due to earthquake or wind load, modeling errors can often cause the problems of instability and performance degradation. In this paper, robust optimal controller design method using H$\infty$ control theory is developed for the systems which have uncertain natural frequency and design constraints. Numerical results show that the proposed H$\infty$ controller can avoid the performance degradation due to several errors and has better performance than conventional LQR method.

• Structural Engineering and Mechanics
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• 제8권2호
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• pp.193-205
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• 1999

A formulation for the dynamic stability analysis of cylindrical shells resting on elastic foundations is presented. In this previously not studied problem, a normal-mode expansion of the partial differential equations of motion, which includes the effects of the foundation as well as a harmonic axial loading, yields a system of Mathieu-Hill equations the stability of which is analyzed using Bolotin's method. The present study examines the effects of the elastic foundation on the instability regions of the cylindrical shell for the transverse, longitudinal and circumferential modes.

• Steel and Composite Structures
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• 제22권2호
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• pp.399-409
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• 2016

The fracture propagation mechanism and fractured rock mass failure mechanism were important research in geotechnical engineering field. Many failures and instability in geotechnical engineering were related on fractures propagation, coalescence and interaction in rock mass under the external force. Most of the current research were limited to two-dimensional for the brittleness and transparency of three-dimensional fracture materials couldn't meet the requirements of the experiment. New materials with good transparent and brittleness were developed by authors. The making method of multi fracture specimens were established and made molds that could be reused. The tension-compression ratio of the material reached above 1/6 in normal temperature. Uniaxial and biaxial loading tests of single and double fracture specimens were carried out. Four new fractures were not found in the experiment of two-dimensional fractures such as the fin shaped crack, wrapping wing crack and petal crack and anti-wing crack. The relationship between stress and strain of the specimens were studied. The specimens with the load had experienced four stages of deformation and the process of the fracture propagation was clearly seen in each stage. The expansion characteristics of the fractured specimens were more obvious than the previous research.

• 한국전산구조공학회논문집
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• 제17권3호
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• pp.225-239
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• 2004

이 논문에서는 철근콘크리트 골조 구조물의 시공 시 작용하는 사하중, 활하중, 시공하중 등의 하중에 대한 지지 및 안전한 시공을 위해 설치되는 지지시스템에 대하여 보다 체계적인 분석이 이루어졌다. 지지시스템의 종류, 비계의 강성과 간격 등의 변화에 따른 구조물의 거동특성을 비교, 분석하였고, 기존의 설계규준 및 해석방법과의 비교를 위해 크리프 등의 시간의존적 거동을 고려한 경우와 괴려하지 않은 경우에 대하여 해석이 수행되었으며, 나무 비계를 사용한 경우와 강재 비계를 사용한 경우에 대한 비교 검토가 이루어졌다. 또한, 대표적인 3-경간 구조물에 대한 해석을 수행하여 내측 기둥과 외측 기둥의 부등축소에 따른 영향을 반영한 검토가 이루어졌다. 나아가 다양한 설계인자의 변화에 따른 거동분석을 통해 2SlR 지지시스템이 가장 효율적임을 제시하였다.

• 국제초고층학회논문집
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• 제2권3호
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• pp.271-283
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• 2013

This paper introduces the current status of high-rise building design in Japan, with reference to some recent projects. Firstly, the design approval system and procedures for high-rise buildings and structures in Japan are introduced. Then, performance-based wind-resistant design of a 300 m-high building, Abeno Harukas, is introduced, where building configuration, superstructure systems and various damping devices are sophisticatedly integrated to ensure a higher level of safety and comfort against wind actions. Next, design of a 213 m-high building is introduced with special attention to habitability against the wind-induced horizontal motion. Finally, performance-based wind-resistant design of a 634 m-high tower, Tokyo Sky Tree, is introduced. For this structure, the core column system was adopted to satisfy the strict design requirements due to the severest level of seismic excitations and wind actions.

• International Journal of Aeronautical and Space Sciences
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• 제18권3호
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• pp.485-497
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• 2017

The pogo phenomenon refers to a type of multidiscipline-related instability found in space launch vehicles. It is caused by coupling between the fuselage structure and other structural propulsion components. To predict the pogo phenomenon, it is essential to undertake adequate structural modeling and to understand the characteristics of the feedlines and the propulsion system. To do this, a modal analysis is conducted using axisymmetric two-dimensional shell elements. The analysis is validated using examples of existing launch vehicles. Other applications and further plans for pogo analyses are suggested. In addition, research on the pogo phenomenon of Saturn V and the space shuttle is conducted in order to constitute a pogo stability analysis using the results of the present modal analysis.

• Genomics & Informatics
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• 제6권3호
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• pp.142-146
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• 2008

In order to understand the protein functions that are related to disease, it is important to detect the correlation between amino acid mutations and disease. Many mutation studies about disease-related proteins have been carried out through molecular biology techniques, such as vector design, protein engineering, and protein crystallization. However, experimental protein mutation studies are time-consuming, be it in vivo or in vitro. We therefore performed a bioinformatic analysis of known disease-related mutations and their protein structure changes in order to analyze the correlation between mutation and disease. For this study, we selected 111 diseases that were related to 175 proteins from the PDB database and 710 mutations that were found in the protein structures. The mutations were acquired from the Human Gene Mutation Database (HGMD). We selected point mutations, excluding only insertions or deletions, for detecting structural changes. To detect a structural change by mutation, we analyzed not only the structural properties (distance of pocket and mutation, pocket size, surface size, and stability), but also the physico-chemical properties (weight, instability, isoelectric point (IEP), and GRAVY score) for the 710 mutations. We detected that the distance between the pocket and disease-related mutation lay within $20\;{\AA}$ (98.5%, 700 proteins). We found that there was no significant correlation between structural stability and disease-causing mutations or between hydrophobicity changes and critical mutations. For large-scale mutational analysis of disease-causing mutations, our bioinformatics approach, using 710 structural mutations, called "Structural Mutatomics," can help researchers to detect disease-specific mutations and to understand the biological functions of disease-related proteins.

• Wind and Structures
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• 제4권5호
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• pp.367-382
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• 2001

Wind tunnel tests were conducted on a model of deck section from the Ting Kau cable stayed bridge. The purpose of the tests was to determine the set of aerodynamic derivatives conventionally used to describe the motion-induced forces arising from the wind flow, and to investigate the stability of the deck under different conditions of turbulence and angle of attack. The study shows that except for large negative angles of attack the deck section itself is stable up to a high wind speed, and that when instability does occur it is essentially a single degree of freedom (torsional) flutter.