• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.05a
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• pp.971-977
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• 2005

Power Flow Analysis (PFA) is developed for the effective predictions of frequency-averaged vibrational response in medium-to-high frequency ranges. In PFA, the power coefficients of semi-infinite structure and for-field energy density are used to predict the vibrational responses of structures. Generally, at high frequencies, PFA can predict narrow-band frequency-averaged vibrational responses of built-up structures. However, in low- to medium frequency ranges, the dynamic responses obtained by PFA represent broad-band frequency-averaged vibrational energy densities. For the prediction of vibrational response variance in Power Flow Finite Element Method (PFFEM), the variances of input power and joint element matrix describing structural coupling relationship are derived. Finally, for the validity of developed formulation, numerical examples for two co-planer plates are performed and the vibrational response variance of the structure are compared with the results of classical and PFFEM solutions.

• Korean Management Science Review
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• v.4
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• pp.76-83
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• 1987

The machine-part group formation(MPGF) problem arises frequently in FMS planning. By viewing the problem as one of finding good assignments, a powerful solution algorithm is presented. The new algorithm solves the threshold dilemma found in previous solution procedures employing similarity coefficients. It also compared favorably with other existing MPGF algorithms by finding minimum exceptional elements for the tested problems. Furthermore the new algorithm can solve dynamic and more realistic MPGF problems by considering production volumes or costs. Such diverse machine-part relationship values were not considered in previous MPGF studies, which included only 0,1 incidence values. An example problem is solved where production volumes are the elements of MPGF incidence matrix.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.7
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• pp.155-160
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• 2001

A milling process with 45 degree chamfered inserts produces a perfect flat surface only in theory. It is due to many unwanted factors including thermal effect, dynamic effect, the problem of the controller used and the problem of accuracy of the machine tool. In this study, introduced is a method to improve the surface roughness by redesigning of the chamfer angle of the insert, which traditionally has been 45 degree. First, the relationship between the fixed machine coordinate and the relative coordinate on the insert is derived. This transfer matrix is used to determine the new insert angle to maximize the flatness of the machined surface. A newly designed insert is manufactured, and used to carry out the experiment. It is proved that she insert designed by the proposed method produced a much flatter surface than a traditional one.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.1124-1128
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• 1995

This paper presents the appplication of computer vision for the purpose of determing the position of the unknown point in the plane. The presented contrik method is estimate the six view parameters reqresenting the relationship between the image plane coordinates and the real physical coordinates. The estimation of six parameters is indispensable for transforming the 2-dimensional camera coordinates to the 3-dimensional spatial coordinates. Then, the position of unknown point is estimated based on the estimated parameters depending on the cameras. The suitability of this control scheme is demonstrated experimentally by determining of position the unknown point in the plane.

• Korean Management Science Review
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• v.12 no.1
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• pp.51-60
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• 1995

This paper presents a workload based model and cell design support system (CDSS) in manufacturing cell design. The proposed model consider manufacturing factor such as machine capacity, production volume, process time, and cell size. Based on those information, workload is calculated and according to the workload, the relationship between machine and part is represented by the workload matrix. To form the manufacturing cell, correlation similarity coefficient (CSC) among machines are calculated and a pair of machines that has the highest value of CSC is assigned to a machine cell. Repeat the above steps until the desired manufacturing cells are obtained. Finally, a cell design support system that could increase the efficiency in the application of a proposed model is developed. The proposed model and CDSS are illustrated by a numerical example.

• Wind and Structures
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• v.12 no.5
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• pp.401-412
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• 2009

A method is applied for the estimation of structural damage of tall slender structures using natural frequency and displacements measurements by GPS. The relationship between the variation in the global stiffness matrix (or in the stiffness of each finite element) and the change in the natural frequencies of the structure is given. In engineering practice the number of frequencies which can be derived by GPS measurement of long-period structures will be equal to one, two or three first natural frequencies. This allows us in initial studies to detect damage with frequency changes based on forward methods in which the measured frequencies are compared with the predicted analytical data. This idea, of health monitoring from possible changes to natural frequencies, or from a statement of excessive displacements is applied to the Stuttgart TV Tower.

• Computers and Concrete
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• v.9 no.1
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• pp.21-33
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• 2012

This paper presents the numerical simulation of the rigid 12.6 mm diameter kinetic energy ogive-nosed projectile impact on plain and fiber reinforced concrete (FRC) targets with compressive strengths from 45 to 235 MPa, using a three-dimensional finite element code LS-DYNA. A combined dynamic constitutive model, describing the compressive and tensile damage of concrete, is implemented. A modified Johnson_Holmquist_Cook (MJHC) constitutive relationship and damage model are incorporated to simulate the concrete behavior under compression. A tensile damage model is added to the MJHC model to analyze the dynamic fracture behavior of concrete in tension, due to blast loading. As a consequence, the impact damage in targets made of plain and fiber reinforced concrete with same matrix material under same impact velocities (650 m/s) are obtained. Moreover, the damage distribution of concrete after penetration is procured to compare with the experimental results. Numerical simulations provide a reasonable prediction on concrete damage in both compression and tension.

• Wind and Structures
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• v.8 no.1
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• pp.13-34
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• 2005

This paper presents an analysis of wind velocity and pressure data obtained in a rural environment with a view to identifying the vortex structures present within the flow and examining the relationship between pressure and dynamic pressure. The data is analysed using both conventional analysis and conditional sampling. A method examining the eigenvalues of a matrix formed by the addition of the square of the strain tensor and the square of the vorticity tensor is also investigated. This method illustrates that there are a number of vortex structures present in the flow. The work presented in this paper suggests that the extreme events occur as a result of the superposition of two independent mechanisms.

• Journal of Microbiology and Biotechnology
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• v.20 no.9
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• pp.1266-1275
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• 2010

Isozyme and protein electrophoresis data from mycelial extracts of 27 isolates of Trichoderma harzianum, 10 isolates of T. aureoviride, and 10 isolates of T. longibrachiatum from Southern Peninsular Malaysia were investigated. The eight enzyme and a single protein pattern systems were analyzed. Three isozyme and total protein patterns were shown to be useful for the detection of three Trichoderma species. The isozyme and protein data were analyzed using the Nei and Li Dice similarity coefficient for pairwise comparison between individual isolates, species isolate group, and for generating a distance matrix. The UPGMA cluster analysis showed a higher degree of relationship between T. harzianum and T. aureoviride than to T. longibrachiatum. These results suggested that the T. harzianum isolates had high levels of genetic variation compared with the other isolates of Trichoderma species.

• Kyungpook Mathematical Journal
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• v.58 no.1
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• pp.91-103
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• 2018

In this paper, we generalize the concept of deferred density to that of deferred f-density, where f is an unbounded modulus and introduce a new non-matrix convergence method, namely deferred f-statistical convergence or $S^f_{p,q}$-convergence. Apart from studying the $K{\ddot{o}}the$-Toeplitz duals of $S^f_{p,q}$, the space of deferred f-statistically convergent sequences, a decomposition theorem is also established. We also introduce a notion of strongly deferred $Ces{\grave{a}}ro$ summable sequences defined by modulus f and investigate the relationship between deferred f-statistical convergence and strongly deferred $Ces{\grave{a}}ro$ summable sequences defined by f.