• Journal of Mechanical Science and Technology
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• 제17권10호
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• pp.1443-1449
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• 2003

Primary goal of adaptive observers would be to estimate the true states of a plant. Identification of unknown parameters is of secondary interest and is achieved frequently with the persistent excitation condition of some regressors. Nevertheless, two problems are linked to each other in the classical approaches to adaptive observers; as a result, we get a good state estimate once after a good parameter estimate is obtained. This paper focuses on the state estimation without parameter identification so that the state is estimated regardless of persistent excitation. In this direction of research, Besancon (2000) recently summarized that most of adaptive observers in the literature share one common canonical form, in which unknown parameters do not affect the unmeasured states. We enlarge the class of linear systems from the canonical form of (Besancon, 2000) by proposing an adaptive observer (with additional dynamics) that allows unknown parameters to affect those unmeasured states. A recursive algorithm is presented to design the proposed dynamic observer systematically. An example confirms the design procedure with a simulation result.

• Communications for Statistical Applications and Methods
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• 제19권1호
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• pp.65-75
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• 2012

실험영역을 벗어난 점에서의 분산을 최소화 하는 외삽-최적의 문제는 모형의 불확실성을 내재하고 있다. 즉, 실험영역을 벗어나게 되면 모형의 불확실성이 높아지므로 모형의 타당성 여부를 진단하여야 한다. 본 연구에서는 외삽(extrapolation) 문제하에서 기본적인 3가지 실험, 즉 제약 실험과 최대최소 실험, 그리고 복합실험 등을 융합한 새로운 제약조건형의 실험 2가지를 제안하였다. 그리고 실험영역의 바깥에 위치한 점의 위치가 실험영역을 얼마나 벗어나느냐에 따른 실험결과에 대한 영향력도 고려하여 보았다. 문제의 특성상 유전 알고리즘을 이용하여 해를 구하였다.

• 대한물리의학회지
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• 제3권1호
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• pp.21-25
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• 2008

Purpose : The objective of this study was conducted to find out the facilitation therapy. Therapeutic exercise concepts are changed from classical therapeutic exercise and neurophysiolosical approach to facilitation therapy. Methods : This is literature study with books and PNF international course books. Results : Facilitation concepts are changed. Complex movements are the result of spinal reflex-mechanism. It was changed the to reflex-reponses are variable and organization of complex movements are determined by the necessity to move. Therefore therapy goals and concepts of spasticity have to change. Conclusion : Facilitation therapy approach by use input systems, which are needed to interact with environmental and task demands. The systems are visual, tactile, propriocepsis, vestibular, acoustical and olfactory. Facilitation therapy need these system all together with shaping.

• 대한한의학원전학회지
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• 제27권3호
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• pp.67-86
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• 2014

Objectives : In this study, I want to work on efficacious porridges through inquiry into the Jukmiryu(粥穈類) based on the classical literature. It is intended to serve as a basic study to explore the modern-day application of dishes that are good as patient meals or healthy foods for elderly people. Methods : I have taken the original text of Jukmiryu(粥穈類) included in Junsaengpaljeon(遵生八牋) and translated it. Further, I have compared it to those porridges treated in Nonohangeon (老老恒言), a book in geriatrics from Ming Dynasty. Results : Nonohangeon(老老恒言) describes sources and effects of 100 porridges. With recipes too simplified, however, it doesn't provide any practical help. In contrast, Junsaengpaljeon(遵生八牋) presents 40 porridges together with their effects and recipes. It is practically more beneficial, as it provides recipes more specific than Nonohangeon(老老恒言). Conclusions : Jukmiryu(粥穈類) in Junsaengpaljeon(遵生八牋) set great store on the pharmacological effects of food. As it provides detailed description of porridge recipes and ingredients as well as their effects, readers can easily apply them to symptoms. Since individuals may choose what would be appropriate for their own symptoms, it could be helpful in not only providing patient meals and foods for elderly people but also improving dietary practice.

• 터널과지하공간
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• 제5권4호
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• pp.363-375
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• 1995

Critical literature review in this study revealed that there can be a significant influence of the residual stress on the engineering properties of rock. The review also showed that few number of research works on the quantification of the influence was attributed to the limitation of the two classical measurement techniques, viz, X-ray diffraction and mechanical relaxation method. In this study, a new way of approach was sought based on the assumption that residual stress up to the failure. A series of hoop tests conducted onthe samples from the limb of Carboniferous Limestone in Clevedon, England, revealed that (i) there is no preferential orientations of microcracks and minerals which have been widely believed as the main source of the strength anisotropy of rock; (ii) the anisotropy of the tensile strength of the limestone results from the influence of the residual stress; (iii) since jointing commenced within the fold, residual stored strain energy has been released preferentially in the direction perpendicular to the major joints(o$^{\circ}$ and 90$^{\circ}$); (ⅳ) during the hoop test making it much easier to create tensile fracture in these directons, viz 45$^{\circ}$ and 135$^{\circ}$)was released during the hoop test making it much easier to create tensile fracture in these directions, viz 45$^{\circ}$and 135$^{\circ}$;(v) the direction in which the stored strain energy may be presumed to be the least, required the greatest work to cause failure.

• 한국전산유체공학회지
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• 제3권1호
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• pp.11-21
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• 1998

A vorticity-based method for the numerical solution of the two-dimensional incompressible Navier-Stokes equations is presented. The governing equations for vorticity, velocity and pressure variables are expressed in an integro-differential form. The global coupling between the vorticity and the pressure boundary conditions is fully considered in an iterative procedure when numerical schemes are employed. The finite volume method of the second order TVD scheme is implemented to integrate the vorticity transport equation with the dynamic vorticity boundary condition. The velocity field is obtained by using the Biot-Savart integral. The Green's scalar identity is used to solve the total pressure in an integral approach similar to the surface panel methods which have been well established for potential flow analysis. The present formulation is validated by comparison with data from the literature for the two-dimensional cavity flow driven by shear in a square cavity. We take two types of the cavity now: (ⅰ) driven by non-uniform shear on top lid and body forces for which the exact solution exists, and (ⅱ) driven only by uniform shear (of the classical type).

• Structural Engineering and Mechanics
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• 제45권1호
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• pp.111-127
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• 2013

In this paper, a new version of gravitational search algorithm based on opposition-based learning (OBGSA) is introduced and applied for optimum design of reinforced concrete retaining walls. The new algorithm employs the opposition-based learning concept to generate initial population and updating agents' position during the optimization process. This algorithm is applied to minimize three objective functions include weight, cost and $CO_2$ emissions of retaining structure subjected to geotechnical and structural requirements. The optimization problem involves five geometric variables and three variables for reinforcement setups. The performance comparison of the new OBGSA and classical GSA algorithms on a suite of five well-known benchmark functions illustrate a faster convergence speed and better search ability of OBGSA for numerical optimization. In addition, the reliability and efficiency of the proposed algorithm for optimization of retaining structures are investigated by considering two design examples of retaining walls. The numerical experiments demonstrate that the new algorithm has high viability, accuracy and stability and significantly outperforms the original algorithm and some other methods in the literature.

• Smart Structures and Systems
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• 제25권4호
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• pp.409-422
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• 2020

This article deals with the flexural analysis of anti-symmetric cross-ply laminated plates under nonlinear thermal loading using a refined plate theory with four variables. In this theory, the undetermined integral terms are used and the number of variables is reduced to four, instead of five or more in other higher-order theories. The boundary conditions on the top and the bottom surfaces of the plate are satisfied; hence the use of the transverse shear correction factors is avoided. The principle of virtual work is used to obtain governing equations and boundary conditions. Navier solution for simply supported plates is used to derive analytical solutions. For the validation of the present theory, numerical results for displacements and stresses are compared with those of classical, first-order, higher-order and trigonometric shear theories reported in the literature.

• Structural Engineering and Mechanics
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• 제18권1호
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• pp.41-58
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• 2004

The postbuckling behaviour of thin shells has fascinated researchers because the theoretical prediction and their experimental verification are often different. In reality, shell panels possess small imperfections and these can cause large reduction in static buckling strength. This is more relevant in thin laminated composite shells. To study the postbuckling behaviour of thin, imperfect laminated composite shells using finite elements, explicit incremental or secant matrices have been presented in this paper. These incremental matrices which are derived using Marguerre's shallow shell theory can be used in combination with any thin plate/shell finite element (Classical Laminated Plate Theory - CLPT) and can be easily extended to the First Order Shear deformation Theory (FOST). The advantage of the present formulation is that it involves no numerical approximation in forming total potential energy of the shell during large deformations as opposed to earlier approximate formulations published in the literature. The initial imperfection in shells could be modeled by simply adjusting the ordinate of the shell forms. The present formulation is very easy to implement in any existing finite element codes. The secant matrices presented in this paper are shown to be very accurate in tracing the postbuckling behaviour of thin isotropic and laminated composite shells with general initial imperfections.

• Computers and Concrete
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• 제25권1호
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• pp.83-94
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• 2020

The use of fly ash in modern-day concrete technology aiming sustainable constructions is on rapid rise. Fly ash, a spinoff from coal calcined thermal power plants with pozzolanic properties is used for cement replacement in concrete. Fly ash concrete is cost effective, which modifies and improves the fresh and hardened properties of concrete and additionally addresses the disposal and storage issues of fly ash. Soft computing techniques have gained attention in the civil engineering field which addresses the drawbacks of classical experimental and computational methods of determining the concrete compressive strength with varying percentages of fly ash. In this study, models based on soft computing techniques employed for the prediction of the compressive strengths of fly ash concrete are collected from literature. They are classified in a categorical way of concrete strengths such as control concrete, high strength concrete, high performance concrete, self-compacting concrete, and other concretes pertaining to the soft computing techniques usage. The performance of models in terms of statistical measures such as mean square error, root mean square error, coefficient of correlation, etc. has shown that soft computing techniques have potential applications for predicting the fly ash concrete compressive strengths.