• Title/Summary/Keyword: Structure and dynamics

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Nonlinear Characteristics of Low-speed Flow Induced Vibration for the Safety Design of Micro Air Vehicle

  • Chang, Tae-Jin;Kim, Dong-Hyun;Lee, In
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.12 no.11
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    • pp.873-881
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    • 2002
  • The fluid induced vibration (FIV) phenomena of an equivalent airfoil system of MAV have been investigated in low Reynolds number flow region. Unsteady flows with viscosity are computed using two-dimensional incompressible Navier-Stokes equations. The present fluid/structure interaction analysis is based on one of the most accurate computational approach with computational fluid dynamics (CFD) and computational structural dynamics (CSD) techniques. The highly nonlinear fluid/structure interaction phenomena due to severe flow separations have been analyzed for the low Reynolds region that has a dominancy of flow viscosity. The effects of Reynolds number and initial angle of attack on the fluid/structure coupled vibration instability are shown and the qualitative trend of FIV phenomenon is investigated.

The Pseudo-Covariational Reasoning Thought Processes in Constructing Graph Function of Reversible Event Dynamics Based on Assimilation and Accommodation Frameworks

  • Subanji, Rajiden;Supratman, Ahman Maedi
    • Research in Mathematical Education
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    • v.19 no.1
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    • pp.61-79
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    • 2015
  • This study discussed about how pseudo-thinking process actually occurs in the mind of the students, used Piaget's frame work of the assimilation and accommodation process. The data collection is conducted using Think-Out-Loud (TOL) method. The study reveals that pseudo thinking process of covariational reasoning occurs originally from incomplete assimilation, incomplete accommodation process or both. Based on this, three models of incomplete thinking structure constructions are established: (1) Deviated thinking structure, (2) Incomplete thinking structure on assimilation process, and (3) Incomplete thinking structure on accommodation process.

Coherent Two-Dimensional Optical Spectroscopy

  • Cho, Min-Haeng
    • Bulletin of the Korean Chemical Society
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    • v.27 no.12
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    • pp.1940-1960
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    • 2006
  • Theoretical descriptions of two-dimensional (2D) vibrational and electronic spectroscopy are presented. By using a coupled multi-chromophore model, some examples of 2D spectroscopic studies of peptide solution structure determination and excitation transfer process in electronically coupled multi-chromophore system are discussed. A few remarks on perspectives of this research area are given.

THE ROBUST CONTROLLER DESIGN FOR UNCERTAIN MULTIVARIABLE SYSTEM USING SWITCHING DYNAMICS

  • Park, Gwi-Tae;Kuo, Chun-Ping;Kim, Dong-Sik;Lim, Sung-Jun
    • 제어로봇시스템학회:학술대회논문집
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    • 1989.10a
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    • pp.924-930
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    • 1989
  • This paper presents the design of simple robust controller for a class of uncertain multivariable systems. We introduce switching dynamics instead of switching logics unlike variable structure control scheme. Also, we can construct the continuous control law from this switching dynamics and consequently remove the chattering motion. The dynamic equations of the range-space of a switching surface matrix C and uniform ultimate boundedness in the presence of parameter uncertainties are described mathematically.

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Intramolecular Hydrogen Bonds in Proteinase Inhibitor Protein, A Molecular Dynamics Simulation Study

  • Chung, Hye-Shin
    • BMB Reports
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    • v.29 no.4
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    • pp.380-385
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    • 1996
  • Ovomucoid third domain is a serine proteinase inhibitor protein which consists of 56 amino acid residues. A fifty picosecond molecular dynamics (MD) simulation was carried out for ovomucoid third domain protein with 5 $\AA$ layer of water molecules. A comparison of main chain atoms in the MD averaged structure with the crystal structure showed that most of the backbone structures are maintained during the simulation. Investigation of the intramolecular hydrogen bondings indicated that most of the interactions between main chain atoms were conserved, whereas those between side chains were reorganized for the period of the simulation. Especially, the side chain interactions around the scissile bond of reactive site P1 (Met18) were found to be more extensive for the MD structures. During the simulation, hydrogen bonds were maintained between the side chains of Glu19 and Arg21 as well as those of Thr17 and Glu19. Extensive side chain interactions observed in the MD structures may shed light on the question of why protein proteinase inhibitors are strong inhibitors for proteinases rather than good substrates.

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Dynamic Modeling of Green Building Certification Criteria Using System Dynamics (시스템 다이내믹스를 활용한 친환경건축물 인증기준의 동태모형 개발에 관한 연구)

  • Choi, Woo Ram;Lee, Hyo Won
    • KIEAE Journal
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    • v.9 no.5
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    • pp.53-61
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    • 2009
  • Green Building Certification System currently going into effect is a static evaluation model. Therefore, as far as the sustainable development of certification system is concerned, further long-term evaluation is required. The main purpose of this study is to offer a model in a way of developing and verifying a dynamic model in Green Building Certification. A dynamic model development has been given System Dynamics based on the causal structure. Thus, this study focused on searching the causal structure of certification criteria and verifying the reality of the model through simulation processing after developing a model. In conclusion, the development of dynamic evaluation method can be attributed to systematic evaluation for the criteria of Certification System.

Gambler's Fallacy Bias on the Supply Chain (도박사 오류 바이어스가 공급사슬에 미치는 영향에 관한 연구)

  • Moon, Seong-Am;Park, Young-Il;Seok, Sun-Bok
    • Korean System Dynamics Review
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    • v.12 no.4
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    • pp.157-175
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    • 2011
  • The purpose of this paper is to find out the effects of the gambler's fallacy bias on the supply chain. For this study, the simulation was based on a casual structure of the Beer Distribution Game from Sterman(2000)'s Business Dynamics and designed into 2 different models : the first model carries the exact same structure as the reference mentioned above and for the second model, the comparison model is used reflecting gambler's fallacy bias. Each model has 2 different demand patterns. The 4 cases of models was tested with 1,000 different random number seeds. The results for the simulation are following : In the aspect of the inventory and out of stock, the basic model resulted better than the comparison. However, in the bullwhip effect, the comparison model has less than the basic in terms of the level demand pattern. But there was no significant difference in the cycle demand.

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Error elimination for systems with periodic disturbances using adaptive neural-network technique (주기적 외란을 수반하는 시스템의 적응 신경망 회로 기법에 의한 오차 제거)

  • Kim, Han-Joong;Park, Jong-Koo
    • Journal of Institute of Control, Robotics and Systems
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    • v.5 no.8
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    • pp.898-906
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    • 1999
  • A control structure is introduced for the purpose of rejecting periodic (or repetitive) disturbances on a tracking system. The objective of the proposed structure is to drive the output of the system to the reference input that will result in perfect following without any changing the inner configuration of the system. The structure includes an adaptation block which learns the dynamics of the periodic disturbance and forces the interferences, caused by disturbances, on the output of the system to be reduced. Since the control structure acquires the dynamics of the disturbance by on-line adaptation, it is possible to generate control signals that reject any slowly varying time-periodic disturbance provided that its amplitude is bounded. The artificial neural network is adopted as the adaptation block. The adaptation is done at an on-line process. For this , the real-time recurrent learning (RTRL) algoritnm is applied to the training of the artificial neural network.

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Molecular Dynamics Simulation Studies of Zeolite-A. Ⅰ. Structure and Dynamics of $Na^+$ Ions in Rigid Dehydrated Zeolite-A Framework

  • Moon Gyeong Keun;Choi Sang Gu;Kim Han Soo;Lee Song Hi
    • Bulletin of the Korean Chemical Society
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    • v.13 no.3
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    • pp.317-324
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    • 1992
  • Structure and dynamics of $Na^+$ ions are investigated by molecular dynamics simulations of rigid dehydrated zeolite-A at several temperatures using a simple Lennard-Jones potential plus Coulomb potential. A best-fitted set of electrostatic charges is chosen from the results of simulation at 298.15 K and Ewald summation technique is used for the long-ranged character of Coulomb interaction. The calculated x, y, and z coordinates of $Na^+$ ions are in good agreement with the positions determined by X-ray crystallography within statistical errors, their random movings in different types of closed cages are well described by time-correlation functions, and $Na_Ⅰ$ type ions are found to be less diffusive than $Na_Ⅱ$ and $Na_{III}$. At 600.0 K, the unstable $Na_{III}$ type ion pushes down one of nearest $Na_{I}$ ions into the $\beta-cage$ and sits on the stable site Ⅰ, and the captured ion in the $\beta-cage$ wanders over and attacks one of 8 $Na_{I}$ type ions.