• Journal of Advanced Marine Engineering and Technology
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• v.25 no.5
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• pp.1130-1139
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• 2001

Springs are widely utilized in machine element. To find out stiffness of coil spring, the space beam theory using the finite element method is adopted in this paper. In three dimensional space, a space frame element is a straight bar of uniform cross section which is capable of resisting axial forces, bending moments about two principal axes in the plane of its cross section and twisting moment about its centroidal axis. The corresponding displacement degrees of freedom are twelve. The displacements of nodal points due to small increment of force are calculated by the finite element method and the calculated nodal displacements are added to coordinates of nodal points. The new stiffness matrix of the system using the new coordinates of nodal points is adopted to calculated the another increments of nodal displacements, that is, the step by step method is used in this paper. The results of the finite element method are fairly well agreed with those of various experiments. Using MATLAB program developed in this paper, spring constants can be predicted by input of few factors.

• Journal of Advanced Marine Engineering and Technology
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• v.21 no.3
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• pp.246-255
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• 1997

The wave washer springs are expected to behave non-linearly between forces and displace¬ments due to contractions of the height and due to expansions in radial direction. To find out the non -linearity of wave washer springs, the three dimensional plate analysis theory using the finite element method is adopted in this paper. The wave washer springs are considered to be three dimensional plate structures rather than frame structures, because their thickness is normally much smaller than their width. The displacements of nodal points due to small increment of force are calculated by the finite element method and the calculated nodal displacements are added to X - Y Z coordinates of nodal points. The new stiffness matrix of the system using the new coordinates of nodal points is adopted to calculate the another nodal displacements, that is, the step by step method is used in this paper. The relations between the increments of forces and displacements in each step are recorded and plotted in chart. The experimental results are compared with the calculated chart and it is shown that there are good coincidences between measured values and calculated ones.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2001.11a
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• pp.21-27
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• 2001

Springs are widely utilized in machine element. To find out stiffness of frustum-shaped coil spring, the space beam theory using the finite element method is adopted in this paper In three dimensional space, a space frame element is a straight bar of uniform cross section which is capable of resisting axial forces, bending moments about two principal axes in the plane of its cross section and twisting moment about its centroidal axis. The corresponding displacement degrees of freedom are twelve. To find out load vector of coil spring subjected to distributed compression, principle of virtual work is adapted The displacements of nodal points due to small increment of force are calculated by the finite element method and the calculated nodal displacements are added to coordinates of nodal points. The new stiffness matrix of the system using the new coordinates of nodal points is adopted to calculate the another increments of nodal displacements, that is, the step by step method is used in this paper. The results of the finite element method are fairly well agreed with those of various experiments. Using MATLAB program developed in this paper, spring constants and stresses can be predicted by input of few factors.

• Journal of Advanced Marine Engineering and Technology
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• v.23 no.4
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• pp.504-513
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• 1999

Usually bellows are designed for the purpose of absorbing axial movement. To find out axial stiffness of bellows the axisymmetric shell theory using the finite element method is adopted in this paper. Bellows can be idealised by series of conical frustum-shaped elements because it is axisymmetric shell structure. The force required to deflect bellows axilly is a function of the dimensions of the bellows and the materials from which they are made. The displancements of nodal points due to small increment of force are calculated by the finite element method and the calculated nodal displacements are added to r-z cylinderical coordinates of nodal points. The new stiffness matrix of the system using the new coordinates of nodal points is adopted to calculate the another increments of nodal dis-placements that is the step by method is used in this paper. spring constant is analyzed according to the changing geometric factors of u-shaped bellows. The FEM results were agreed with experiment. Using developed FORTRAN PROGRAM spring constant can be predicted by input of a few factors.

• Journal of Advanced Marine Engineering and Technology
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• v.23 no.5
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• pp.702-710
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• 1999

U-shaped bellows are usually used to piping system pressure sensor and controller for refriger-ator. Bellows subjected to internal pressure are designed for the purpose of absorbing deformation. Internal pressure on the convolution sidewall and end collar will be applied to an axial load tend-ing to push the collar away from the convolutions. To find out deformation behavior of bellow sub-jected to internal pressure the axisymmetric shell theory using the finite element method is adopted in this paper. U-shaped bellows can be idealized by series of conical frustum-shaped ele-ments because it is axisymmetric shell structure. The displacements of nodal points due to small increment of force are calculated by the finite element method and the calculated nodal displace-ments are added to r-z cylindrical coordinates of nodal points. The new stiffness matrix of the sys-tem using the new coordinates of nodal points is adopted to calculate the another increments of nodal displacement that is the step by step method is used in this paper. The force required to deflect bellows axially is a function of the dimensions of the bellows and the materials from which they are made. Spring constant is analyzed according to the changing geometric factors of U-shaped bellows. The FEM results were agreed with experiment. Using developed FORTRAN PROGRAM the internal pressure vs. deflection characteristics of a particu-lar bellows can be predicted by input of a few factors.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.31 no.3 s.258
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• pp.300-305
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• 2007

Many practical flow problems are defined with the circular boundary. Fluid flows within a circular boundary are however susceptible to a singularity problem when the cylindrical coordinates are employed. To remove this singularity a method has been developed in this study which uses the local harmonic functions in discretization of derivatives as well as interpolation. This paper describes the basic reason for introducing the harmonic functions and the overall numerical methods. The numerical methods are evaluated in terms of the accuracy and the stability. The Lamb-dipole flow is selected as a test flow. We will see that the harmonic-function method indeed gives more accurate solutions than the conventional methods in which the polynomial functions are utilized.

• Journal of Biomedical Engineering Research
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• v.23 no.1
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• pp.39-47
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• 2002

The objective of this study is to provide a Precise form of spatial normalization with affine transformation. The quantitative comparison of the brain architecture across different subjects requires a common coordinate system. For the common coordinate system, not only global brain but also a local region of interest should be spatially normalized. Registration using mutual information generally matches the whose brain well. However. a region of interest may not be normalized compared to the feature-based methods with the landmarks. The hybrid method of this Paper utilizes feature information of the local region as well as intensity similarity. Central gray nuclei of a brain including copus callosum, which is used for feature in Schizophrenia detection, is appropriately normalized by the hybrid method. In the results section. our method is compared with mutual information only method and Talairach mapping with schizophrenia Patients. and is shown how it accurately normalizes feature .

• Proceedings of the Korea Society of Information Technology Applications Conference
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• 2002.11a
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• pp.502-511
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• 2002

컴퓨터의 기술적 발전은 사회 여러 분야에 막대한 영향을 끼쳤다. 그중 악보 인식분야에도 커다란 영향을 주었다 그러나, On-line 상에서 그린 악보를 실시간으로 정형화된 악보형태로 변환하는 처리에 대한 연구가 미흡하여 이에 대한 연구가 필요하다. 본 논문에서는 실시간으로 악보를 인식하고, 사용자의 편의를 도모하기 위해 DP(Dynamic Programming) 매칭법을 이용한 On-Line 악보인식에 관한 방법을 제안하였다. 본 연구에서는 실시간으로 입력되는 악상기호를 인식하기 위해, 가장 유효한 정보인 악상 기호내의 방향, x, y 좌표를 이용하여 벡터형태로 추출한 후 음표와 비음표(쉼표, 기타기호)의 두개의 그룹으로 나누어진 표준패턴과의 DP매칭을 통해 인식한다. 먼저 tablet을 통해 실시간으로 악상 기호를 입력할 때 생기는 x, y좌표를 이용하여, 펜의 움직임에 대한 16방향 부호화를 수행한다. 음표와 비음표를 구분하기 위한 시간을 줄이고자 16방향 부호화를 적용하치 않고 사사분면부호화를 적용한다. 음표를 약식으로 그릴 경우 음표 머리에 해당하는 부분의 좌표는 삼사분면에 분포하고, 폐곡선의 음표일 경우에는 좌표가 사사분면에 고르게 나타난다. 폐곡선을 제외한 음표의 머리는 폐곡선과 같은 조건이면서 입력받은 y좌표값들 중에서 최소값과 최대값을 구한 다음 2로 나눈 값을 지나는 y좌표의 개수가 임의의 임계값 이상이면 음표로 판단한다. 위 조건을 만족하지 않을 경우 비음표로 취급한다. 음표와 비음표를 결정한 다음, 입력패턴과 표준패턴과의 DP매칭을 통하여 벌점을 구한다. 그리고 경로탐색을 통해 벌점에 대한 각각의 합계를 구해 최소값을 악상기호로 인식 하였다. 실험결과, 표준패턴을 음표와 비음표의 두개의 그룹으로 나누어 인식함으로써 DP 매칭의 처리 속도를 개선시켰고, 국소적인 변형이 있는 패턴과 특징의 수가 다른 패턴의 경우에도 좋은 인식률을 얻었다.r interferon alfa concentrated solution can be established according to the monograph of EP suggesting the revision of Minimum requirements for biological productss of e-procurement, e-placement, e-payment are also investigated.. monocytogenes, E. coli 및 S. enteritidis에 대한 키토산의 최소저해농도는 각각 0.1461 mg/mL, 0.2419 mg/mL, 0.0980 mg/mL 및 0.0490 mg/mL로 측정되었다. 또한 2%(v/v) 초산 자체의 최소저해농도를 측정한 결과, B. cereus, L. mosocytogenes, E. eoli에 대해서는 control과 비교시 유의적인 항균효과는 나타나지 않았다. 반면에 S. enteritidis의 경우는 배양시간 4시간까지는 항균활성을 나타내었지만, 8시간 이후부터는 S. enteritidis의 성장이 control 보다 높아져 배양시간 20시간에서는 control 보다 약 2배 이상 균주의 성장을 촉진시켰다.차에 따른 개별화 학습을 가능하게 할 뿐만 아니라 능동적인 참여를 유도하여 학습효율을 높일 수 있을 것으로 기대된다.향은 패션마케팅의 정의와 적용범위를 축소시킬 수 있는 위험을 내재한 것으로 보여진다. 그런가 하면, 많이 다루어진 주제라 할지라도 개념이나 용어가 통일되지 않고 사용되며 검증되어 통용되는 측정도구의 부재로 인하여 연구결과의 축적이 미비한 상태이다. 따라서, 이에 대한 재고와 새로운 방향 모색이 필요하다고 사료된다.로 사료되며, 임신관련 cytokine에 대한 다양한 연구가 요구되고 있다.₂/Hf(Variable)/Si 계에서 HfO₂ 박막이 Si 기판위에 직접 증착되면, 순수 HfO₂ 박막의

• The Korean Journal of Nuclear Medicine
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• v.36 no.6
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• pp.317-324
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• 2002

Purpose: The use of statistical parametric mapping (SPM) program has increased for the analysis of brain PET and SPECT images. Montreal Neurological Institute (MNI) coordinate is used in SPM program as a standard anatomical framework. While the most researchers look up Talairach atlas to report the localization of the activations detected in SPM program, there is significant disparity between MNI templates and Talairach atlas. That disparity between Talairach and MNI coordinates makes the interpretation of SPM result time consuming, subjective and inaccurate. The purpose of this study was to develop a program to provide objective anatomical information of each x-y-z position in ICBM coordinate. Materials and Methods: Program was designed to provide the anatomical information for the given x-y-z position in MNI coordinate based on the Statistical Probabilistic Anatomical Map (SPAM) images of ICBM. When x-y-z position was given to the program, names of the anatomical structures with non-zero probability and the probabilities that the given position belongs to the structures were tabulated. The program was coded using IDL and JAVA language for 4he easy transplantation to any operating system or platform. Utility of this program was shown by comparing the results of this program to those of SPM program. Preliminary validation study was peformed by applying this program to the analysis of PET brain activation study of human memory in which the anatomical information on the activated areas are previously known. Results: Real time retrieval of probabilistic information with 1 mm spatial resolution was archived using the programs. Validation study showed the relevance of this program: probability that the activated area for memory belonged to hippocampal formation was more than 80%. Conclusion: These programs will be useful for the result interpretation of the image analysis peformed on MNI coordinate, as done in SPM program.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.5
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• pp.943-951
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• 1992

The objectives of this study are to analyse the thermal response behavior occurring in the charring ablative material more realistically by considering ablation and char phenomena occurring in several material layers, and to increase the reliability of thermal analysis by being able to get stable solutions through using the finite analytic method. A program has been developed to predict the temperature distribution, ablation thickness, char thickness, ablation velocity and char velocity by solving non-linear one-dimensional heat conduction equation. Results of calculation were compared with results of published papers. From this compariosn this program was proved to be a very good tool for thermal design and analysis of charring ablative materials used in the rocket propulsion system.