• Journal of the Computational Structural Engineering Institute of Korea
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• v.22 no.4
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• pp.335-341
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• 2009

In this paper, review of developed MLS-based finite elements and a proposal for their applications are described. The shape functions and their derivatives of MLS-based finite elements are constructed using Moving-Least Square approximation. In MLS-based finite element, using the adequate influence domain of weight function used in MLS approximation, kronecker delta condition could be satisfied at the element boundary. Moreover, because of the characteristics of MLS approximation, we could easily add extra nodes at an arbitrary position in MLS-based finite elements. For these reasons, until now, several variable-node elements(2D variable element for linear case and quadratic case and 3D variable-node elements) and finite crack elements are developed using MLS-based finite elements concept. MLS-based finite elements could be extended to 2D variable-node triangle element, 2D finite crack triangle element, variable-node shell element, finite crack shell element, and 3D polyhedron element. In this paper, we showed the feasibility of 3D polyhedron element at the case of femur meshing.

• YAKHAK HOEJI
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• v.50 no.3
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• pp.199-203
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• 2006

A new type of macrolides, lincosamides and streptogramin B antibiotics (MLS) resistance, showing the characteristic phenotype growing within the inhibition zone area around the clindamycin disk, was identified among clinically isolated Staphylococcus aureus. We named the phenotype as MLS resistance with foggy-D shape (fMLS). The average frequency of MLS isolates was 9%. All of fMLS isolates have only erm(A) for the resistance determinant. The growth pattern of the challenged MLS isolate looks intermediate phase between the patterns of inducible MLS resistance and constitutive MLS resistance.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.29 no.3
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• pp.237-244
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• 2016

This paper presents a nonlinear Moving Least Squares(MLS) difference method for material nonlinearity problem. The MLS difference method, which employs strong formulation involving the fast derivative approximation, discretizes governing partial differential equation based on a node model. However, the conventional MLS difference method cannot explicitly handle constitutive equation since it solves solid mechanics problems by using the Navier's equation that unifies unknowns into one variable, displacement. In this study, a double derivative approximation is devised to treat the constitutive equation of inelastic material in the framework of strong formulation; in fact, it manipulates the first order derivative approximation two times. The equilibrium equation described by the divergence of stress tensor is directly discretized and is linearized by the Newton method; as a result, an iterative procedure is developed to find convergent solution. Stresses and internal variables are calculated and updated by the return mapping algorithm. Effectiveness and stability of the iterative procedure is improved by using algorithmic tangent modulus. The consistency of the double derivative approximation was shown by the reproducing property test. Also, accuracy and stability of the procedure were verified by analyzing inelastic beam under incremental tensile loading.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.25 no.2
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• pp.139-148
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• 2012

The MLS(Moving Least Squares) Difference Method is a numerical scheme that combines the MLS method of Meshfree method and Taylor expansion involving not numerical quadrature or mesh structure but only nodes. This paper presents an dynamic algorithm of MLS difference method for solving transient solid mechanics problems. The developed algorithm performs time integration by using Newmark method and directly discretizes strong forms. It is very convenient to increase the order of Taylor polynomial because derivative approximations are obtained by the Taylor series expanded by MLS method without real differentiation. The accuracy and efficiency of the dynamic algorithm are verified through numerical experiments. Numerical results converge very well to the closed-form solutions and show less oscillation and periodic error than FEM(Finite Element Method).

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1633-1637
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• 2008

In this study, we developed 3D MLS-based variable-node elements for easy meshing. These elements should be derived from 2D MLS-based variable-node elements and would be utilized as key elements of easy meshing technique we proposed. Using developed 3D MLS-based variable-node elements, we demonstrated several examples having complex configuration compared with conventional meshing technique. Moreover, we compared with the stress results of our model and conventional one.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1996.10a
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• pp.386-393
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• 1996

The paper describes how a Maximum Length Sequence(MLS) and correlation technique in the form of Hadamard transformation may be applied for the measurement of airborne sound reduction. It is shown that in most cases, the values obtained by the MLS technique will be equal to the expected values obtained by the classical method. However, due to the correlation process involved, the MLS method will be much less sensitive to disturbances from extraneous noise. The described method has been implemented in an RTA acoustic analyser.

• Korean journal of food and cookery science
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• v.23 no.6
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• pp.977-986
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• 2007

This study was conducted to evaluate the mechanical (texture and color) and sensory characteristics of mulberry leaf sulgi (MLS) and lotus leaf sulgi (LLS) that contained different ratios of ingredients. MLS and LLS with final concentrations of 0%, 1%, 3% and 5% of powdered mulberry and lotus leaf respectively, were prepared. The texture characteristics (hardness, adhesiveness, springiness, cohesiveness, gumminess, chewiness), color values (lightness, redness, yellowness), and sensory characteristics (color, flavor, moistness, taste, brittleness, chewiness and after-taste) of the different sulgis were then measured and compared. With the exception of gumminess and chewiness, the texture characteristics of 0% MLS, 1% MLS and 3% MLS were not significantly different. The sensory characteristics of 0% MLS had the highest scores, whereas those of 5% MLS were the lowest for all factors except for brittleness. However, with the exception of chewiness, the scores obtained from 0% and 1 % MLS did not differ significantly. In addition, 1% MLS and 3% MLS were not significantly different from each other. Furthermore, the texture characteristics of 0% LLS and 1 % LLS were not different significantly, although the characteristics of 1% LLS were significantly different from those of 3% and 5% LLS when springiness, cohesiveness, and chewiness were considered. Additionally, the sensory characteristics of 0% LLS and 1% LLS were not significantly different, with the exception of brittleness, and the characteristics of 1% LLS and 3% LLS were not significantly different, with the exception of taste and after-taste.

• YAKHAK HOEJI
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• v.51 no.2
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• pp.108-114
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• 2007

The predominant Macrolides-Lincosamide-Streptogramin B (MLS$_B$) antibiotics resistance genes in staphylococci are erm(A) and erm(C). There is the phenomenon that the ratio of constitutively MLS$_B$ antibiotics resistance (cMLS) in erm(A) is much higher than in erm(C). Thus, we confirmed that the difference of the mutation ratio between erm(A) and erm(C) makes the phenomenon. We examined 8 staphylococci carrying inducibly expressed (iMLS) erm(A) or erm(C) genes. After overnight incubation in the presence of the non-inducer MLS$_B$ antibiotics, spontaneous mutants constitutively expressed MLS$_B$ resistance were selected. Against our expectation, the mutation ratio of erm(A) was lower than erm(C). Therefore, possibilities of other factors determining the ratio of cMLS phenotype might be concerned. All the mutants showed sequence alterations in translational attenuator and all the alterations seemed to give rise to change the second structure of mRNA to express constitutively. For erm(A), 4 different types of sequence deletions ranging from 72 bp to 122 bp and 3 different types of duplications ranging 24 bp to 93 bp were detected. Also, there were 9 different types of duplications ranging 15bp to 154bp in erm(C).

• Journal of the Computational Structural Engineering Institute of Korea
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• v.31 no.6
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• pp.331-337
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• 2018

This paper presents dynamic algorithm of the MLS(moving least squares) difference method using first order differential Approximation. The governing equations are only discretized by the first order MLS derivative approximation. The system equation consists of an assembly of the approximate function, so the shape of system equation is similar to FEM(finite element method). The CDM(central difference method) is used for time integration of dynamic equilibrium equation. The natural frequency analyses of the MLS difference method and FEM are performed, and two analysis results are compared. Also, the accuracy of the proposed numerical method is verified by displaying the dynamic analysis results together with the results by the existing second order differential approximation. In the process of assembling the first order MLS derivative approximation, the oscillation error was suppressed and the stress distribution was interpreted as relatively uniform.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2009.04a
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• pp.51-54
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• 2009

본 논문에서는 MLS기반 유한요소에 대한 개략적인 현재 개발상황과 향후 예상할 수 있는 응용분야에 대한 제안을 하였다. 이동최소제곱근사를 이용하여 형상함수를 생성하는 MLS기반 유한요소는, 요소의 경계에서 기존 유한요소의 성질-크로네커 델타 조건-을 가지면서도 기존 요소가 갖지 못했던 임의의 절점추가가 자유롭다는 장점이 있어 다양한 변절점요소로의 개발이 이루어져왔다. 선형 또는 이차형상함수를 갖는 2차원 변절점요소 뿐 아니라, 균열선단과 균열면을 포함하고 있는 2차원 균열요소와 3차원에서의 제한적인 변절점요소 등이 개발되어 다양한 불연속성 문제에 적용 가능함이 입증되었다. 이러한 MLS기반 유한요소는 향후 2차원 변절점 3각요소, 2차원 삼각균열요소, 변절점 쉘요소, 균열 쉘요소, 마칭큐브알고리즘에 적합한 3차원 변절점요소로의 개발이 가능할 것으로 예상되며, 본 논문에서는 3차원 변절점요소를 이용한 복잡한 요소망 생성에 대한 예제로 대퇴골의 요소망 생성을 보였다.