• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 1996년도 추계학술대회논문집; 한국과학기술회관, 8 Nov. 1996
• /
• pp.224-230
• /
• 1996

In the mechanical systems with large damping, the conventional SDM method developed for no damping systems will lead to an error solution. Here, we introduce a SDM method based on the experimental modal model for large damping systems. The sensitivities of natural frequencies and mode shapes with respect to mass, damping, and stiffness coefficients of structures are used to calculate the position and quantity of modification, and predict the new dynamic characteristics. Through numerical simulation and experiment, the effectiveness of the proposed method is tested.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2009년도 춘계학술대회 논문집
• /
• pp.811-812
• /
• 2009

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2010년도 춘계학술대회 논문집
• /
• pp.328-329
• /
• 2010

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2002년도 춘계학술대회논문집
• /
• pp.651-659
• /
• 2002

Component Mode Synthesis (CMS) is a dynamic substructuring technique to get an approximate eigensolutions of large degree-of-freedom structures divisible into several components. But, In practice. most of large structures are modeled by different teams of engineers. and their respective finite element models often require different mesh resolutions. As a result, the finite element substructure models can be non-conforming and/or incompatible. In this work, A hybrid version of component mode synthesis using a localized lagrange multiplier to treat the non-conforming mesh problem was derived. Evolution Strategies (ESs) is a stochastic numerical optimization technique and has shown a robust performance for solving deterministic problems. An ESs conducts its search by processing a population of solutions for an optimization problem based on principles from natural evolution. An optimization example for raising the first natural frequency of a plate structure using beam stiffeners was presented using hybrid component mode synthesis and robust evolution strategies (RES) optimization technique. In the example. the design variables are the positions and lengths of beam stiffeners.

• 한국유체기계학회 논문집
• /
• 제14권5호
• /
• pp.48-54
• /
• 2011

Structural modifications of a ship may cause a fatal accident such as sinking and wrecking of ship. Especially, barge ship can be easily reconstructed to load more bulk cargo. In this study, for a real accident case, change of mooring force due to structural modification was analyzed to evaluate accident risk. A two dimensional dynamic model for the barge ship was constructed to compute mooring forces with related to floating motion. The equation of motion was established in Matlab code and buoyancy was calculated by using direct integration of submerged volume. The results showed that wind force, current force, and mooring force after rebuilding was approximately 4.3 kN, 14 kN, 1,561 kN respectively. The maximum force of mooring force according to the length of mooring cable were 1,614 kN at 30 m of mooring cable. Thus, an arbitrary modification of ship lead instability and unreliable result so that illegal rebuilding of ship should be avoided.

• BMB Reports
• /
• 제34권1호
• /
• pp.1-7
• /
• 2001

Structural and physical properties of type wild type and various selected mutants of the vnd/NK-2 homeodomain, the protein product of the homeobox, and the implication in genetic disease are reviewed. The structure, dynamics and thermodynamics have been Investigated by NMR and by calorimetry. The interactions responsible for the nucleotide sequence-specific binding of the homeodomain to its consensus DNA binding site have been identified. There is a strong correlation between significant structural alterations within the homeodomain or its DNA complex and the appearance of genetic disease. Mutations in positions known to be important in genetic disease have been examined carefully For example, mutation of position 52 of vnd/NK-2 results in a significant structural modification and mutation of position 54 alters the DNA binding specificity and amity The $^{15}N$ relaxation behavior and heteronuclear Overhauser effect data was used to characterize and describe the protein backbone dynamics. These studies were carried out on the wild type and the double mutant proteins both in the free and in the DNA bound states. Finally, the thermodynamic properties associated with DNA binding are described for the vnd/NK-2 homeodomain. These thermodynamic measurements reinforce the hypothesis that water structure around a protein and around DNA significantly contribute to the protein-DNA binding behavior. The results, taken together, demonstrate that structure and dynamic studies of proteins combined with thermodynamic measurements provide a significantly more complete picture of the solution behavior than the individual studies.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2005년도 추계학술대회논문집
• /
• pp.852-855
• /
• 2005

Structural Dynamic Modification(SDM) is a technique to improve structure's dynamic characteristics by adding and removing substructures or changing material properties and shape of structures. This paper describes SDM techniques applied to a large structure with too many DOFs. The goal of this SDM technique is to modify a targe structure efficiently for its natural frequencies to avoid excitation frequencies. In this case, models reduced by Component Mode Synthesis(CMS) method that is a coupling technique are used to analyze a large structure efficiently. This paper considers a helicopter deck model with 55,000 DOFs as an application.

• 정보저장시스템학회논문집
• /
• 제5권2호
• /
• pp.76-81
• /
• 2009

Mobile devices have become an important part of daily life. This is especially true of laptop PCs, which are portable enough to be used almost anywhere. Laptop PCs, however, cannot be nomadic if each component is not robust enough to endure rugged laptop operating environment. Generally, external shock makes collision on head-disk interface and damage to read-write performance. To minimize the likelihood of failure, shock analysis must be incorporated into the design of hard disk drive in laptop. This research explores the structure modification of laptop HDD base, for improving shock performance using finite element analysis which considers the flexibility of whole HDD structure. FE model is verified by modal test and finely tuned. Then we obtained the transmitted acceleration of spindle and pivot and the relative displacement between disk and slider head as shock response. Based on shock simulation, the structural dynamics modification is performed and the primary design parameters are extracted.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2002년도 추계학술대회논문초록집
• /
• pp.335.1-335
• /
• 2002

Among many structural dynamics modification methods for plate and shell vibration problems, embedding an emboss to the surface is very efficient. But deciding an optimal position and shape using optimization algorithm needs defining geometry and remeshing the model for every iteration step to implement the method, which takes much numerical cost. (omitted)

• BMB Reports
• /
• 제51권5호
• /
• pp.211-218
• /
• 2018

Chromatin is an intelligent building block that can express either external or internal needs through structural changes. To date, three methods to change chromatin structure and regulate gene expression have been well-documented: histone modification, histone exchange, and ATP-dependent chromatin remodeling. Recently, a growing body of literature has suggested that histone tail cleavage is related to various cellular processes including stem cell differentiation, osteoclast differentiation, granulocyte differentiation, mammary gland differentiation, viral infection, aging, and yeast sporulation. Although the underlying mechanisms suggesting how histone cleavage affects gene expression in view of chromatin structure are only beginning to be understood, it is clear that this process is a novel transcriptional epigenetic mechanism involving chromatin dynamics. In this review, we describe the functional properties of the known histone tail cleavage with its proteolytic enzymes, discuss how histone cleavage impacts gene expression, and present future directions for this area of study.