• International Journal of Control, Automation, and Systems
• /
• v.2 no.4
• /
• pp.530-535
• /
• 2004

This paper deals with the unknown input observer (UIO) design problem for a class of linear time-delay systems. A case in which the observer error can completely be decoupled from an unknown input is treated. Necessary and sufficient conditions for the existences of such observers are present. Based on Lyapunov stability theory, thedesign of the observer with internal delay is formulated in terms of linear matrix inequalities (LMI). The design of the observer without internal delay is turned into a stabilization problem in linear systems. Two design algorithms of UIO are proposed. The effect of the proposed approach is illustrated by two numerical examples.

• English Language & Literature Teaching
• /
• v.10 no.1
• /
• pp.1-22
• /
• 2004

The primary purpose of this study is to investigate the applicability of content and formal schemata for processing the scientific texts which encompass the human knowledge of the physical world. In general, schema theory is based on the culture-oriented background of a text. From this point of view, the problem as to whether both content and formal schemata are applicable to the comprehension of a scientific text deserves a focal attention in terms of information processing modes. The results of empirical study indicate that whereas the universality of general knowledge content about the natural world attenuates the tenets of schema theory, the rhetorical organization of scientific texts encourages the application of the schema-based approach; the reader's familiarity with the structural patterns of a text facilitates his reading comprehension.

• Steel and Composite Structures
• /
• v.13 no.2
• /
• pp.157-169
• /
• 2012

Shell structures are very interesting from the design point of view and these are well recognized in the scientific literature. In this paper the analysis of the buckling loads and stability paths of a sandwich conical shell with unsymmetrical faces under combined load based on the assumptions of moderately large deflections (geometrically nonlinear theory) is considered and elastic-plastic properties of the material of the faces are taken into considerations. External load is assumed to be two-parametrical one and it is assumed that the shell deforms into the plastic range before buckling. Constitutive relations in the analysis are those of the Nadai-Hencky deformation theory of plasticity and Prandtl-Reuss plastic flow theory with the H-M-H (Huber-Mises-Hencky) yield condition. The governing stability equations are obtained by strain energy approach and Ritz method is used to solve the equations with the help of analytical-numerical methods using computer.

• Language and Information
• /
• v.6 no.2
• /
• pp.129-152
• /
• 2002

This paper argues for a need to adopt a conceptually radical approach to zero anaphora resolution in Korean. It is shown that a number of apparently conflicting constraints, mostly motivated by lexical, syntactic, semantic, and pragmatic factors, are involved in determining the referential identity of zero pronouns in Korean. It is also argued that some of the major concepts of Optimality Theory can provide a good theoretical framework to predict the antecedents to zero pronouns in general. A partial formalization of 07-based constraints at the morpho-syntactic and lexico-semantical level is provided. It is argued that the lexico-semantic restrictions on adjacent expressions play the most important role in the anaphora resolution process along with a variant of the binding principle, formulated in semantic terms. Other pragmatically motivated constraints that incorporate some important intuitions of Centering Theory are proposed too.

• Bulletin of the Korean Chemical Society
• /
• v.18 no.9
• /
• pp.976-981
• /
• 1997

The magnetic susceptibilities of molybdenum ions with 4d1 electronic configuration in the octahedral crystal field were calculated on the basis of ligand field theory. The experimental magnetic susceptibilities for molybdenum ions, which are stabilized at the octahedral site in the perovskite lattice of Ba2ScMoⅤO6 and Sr2YMoⅤO6, were compared with the theoretical ones. We have tried to fit their temperature dependence of magnetic susceptibility with ligand field parameters, spin-orbit coupling constant ζSO, and orbital reduction parameter κ according to intermediate field coupling and strong field theory. Strong field coupling theory could not explain experimental curves without unrealistically large axial ligand field, since it ignores the mixing up between different state via spin-orbit interaction and ligand field. On the other hand, the intermediate field coupling theory could successfully reproduce experimental data in octahedral and trigonal ligand field. The fitting result demonstrates not only the fact that spin-orbit interaction is primarily responsible for the variation of magnetic behavior but also the fact that effective orbital overlap, enhanced by cubic crystal structure, reduces significantly orbital angular momentum as indicated by κ parameter.

• Bulletin of the Korean Chemical Society
• /
• v.7 no.3
• /
• pp.224-228
• /
• 1986

A nonlinear theory is presented for the fluctuations of intermediates in the Brusselator near the critical point caused by diffusion. The method used is the two time scaling method different from the conventional method in the sense that a slight nonlinear effect is included in the initial time region where the linear approximation is conventionally valid. The result obtained by the nonlinear theory shows that fluctuations close to the critical point approach the value of a stable steady state or deviate infinitely from an unstable steady state, as time goes to infinity, while the linear theory gives approximately time-independent fluctuations. A brief discussion is given for the correlation at a time between fluctuating intermediates when the system approaches a stable steady state.

• 중국학논총
• /
• no.66
• /
• pp.85-103
• /
• 2020

We use prototypes (also known as referent in semiotics) when we understand the outside world. Different language users use different prototypes to decode the same sound. When we learn Chinese language as a foreign language, during it's sound perceptual process, Korean learners' target language prototypes are different from Chinese native speakers'. The purpose of the paper is to examine the theory of speech perception and the theory of constructivism teaching, and to suggest to the Chinese language teachers to have Cunstructivist approach while they design there teaching course. For this, we concerned three things: First is to review speech perception theory and constructivism teaching theory. Second based on the preceding study, we review that learner's prototypes are different from Chinese native speaker and this cause the error of listening and pronunciation. Finally, we introduced two simple speech visualization programs developed to help us learn pronunciation.

• Structural Engineering and Mechanics
• /
• v.82 no.5
• /
• pp.629-641
• /
• 2022

This study deals with the spinning impact on flap-wise vibration characteristics of nonlocal functionally graded (FG) cylindrical beam based on the Hyperbolic shear deformation beam theory. The nonlocal strain gradient theory is used to investigate the small-scale impact on the nonlocal motion equation as well as corresponding nonlocal boundary conditions. Based on the mathematical simulation and according to the Hamilton principle, the computerized modeling of a rotating functionally graded nanotube is generated, and then, via a numerical approach, the obtained mathematical equations are solved. The calculated outcomes are helpful to the production of Nano-electro-mechanical-systems (NEMS) by investigating some designed parameters such as rotating speed, hub radius, length-scale parameters, volume fraction parameters, etc.

• Structural Engineering and Mechanics
• /
• v.81 no.4
• /
• pp.461-479
• /
• 2022

A finite element method analysis framework is introduced for the free vibration analyses of functionally graded porous beam structures by employing two variables trigonometric shear deformation theory. Both Young's modulus and material density of the FGP beam element are simultaneously considered as grading through the thickness of the beam. The finite element approach is developed using a nonlocal strain gradient theory. The governing equations derived here are solved introducing a 3-nodes beam element. A comprehensive parametric study is carried out, with a particular focus on the effects of various structural parameters such as the dispersion patterns of GPL reinforcements and porosity, thickness ratio, boundary conditions, nonlocal scale parameter and strain gradient parameters. The results indicate that porosity distribution and GPL pattern have significant effects on the response of the nanocomposite beams.

• The Pure and Applied Mathematics
• /
• v.29 no.2
• /
• pp.141-160
• /
• 2022

From the past until now, political and economic relations among countries have been one of the most important issues among analysts and numerous studies have tried to analyze these relations from different theoretical perspectives. The dynamic system of games has introduced a new modeling method in the game theory. In this study, we use behavioral models (level- k) along with the dynamic system in games to model rational agent behavior. As an application, we study Russia- Norway economic and political relations (1970-2019). The dynamic system in games along with behavioral games theory can be used to predict the players behavior in the future.