• Computational Structural Engineering
• /
• v.9 no.2
• /
• pp.115-120
• /
• 1996

The main concern of numerical dynamic analysis of large structures is to find an acceptable solution with fewer mode shapes and less computational efforts. Component mode method utilizes substructure technique to reduce the degree of freedom but have a disadvantage to not consider the dynamic characteristics of loads. Ritz Vector method consider the load characteristics but requires many integrations and errors are accumulated. In this study, to improve the effectiveness of component mode method, Lanczos algorithm is introduced. To prove the effectiveness of this method, example structure are analyzed and the results are compared with SAP90.

• Journal of Korean Association for Spatial Structures
• /
• v.19 no.2
• /
• pp.101-108
• /
• 2019

In this paper, the characteristic of intrinsic mode function(IMF) and its orthogonalization of ensemble empirical mode decomposition(EEMD), which is often used in the analysis of the non-linear or non-stationary signal, has been studied. In the decomposition process, the orthogonal IMF of EEMD was obtained by applying the Gram-Schmidt(G-S) orthogonalization method, and was compared with the IMF of orthogonal EMD(OEMD). Two signals for comparison analysis are adopted as the analytical test function and El Centro seismic wave. These target signals were compared by calculating the index of orthogonality(IO) and the spectral energy of the IMF. As a result of the analysis, an IMF with a high IO was obtained by GSO method, and the orthogonal EEMD using white noise was decomposed into orthogonal IMF with energy closer to the original signal than conventional OEMD.

• Korean Journal of Optics and Photonics
• /
• v.30 no.1
• /
• pp.15-22
• /
• 2019

$Si_3N_4$ rib-optical waveguides for evanescent-wave integrated-optical biosensors were analytically interpreted, to derive the single-mode propagation conditions. The integrated-optical biosensor structure based on two-mode interference was proposed, and the rib width and thickness and core thickness for a single-mode and two-mode waveguide (sensing region) were proposed to be $3{\mu}m$, 2 nm, and 150 nm and $3{\mu}m$, 20 nm, and 340 nm respectively. The optical characteristics of each guided-wave mode were investigated utilizing the film mode-matching (FMM) analysis.

• ETRI Journal
• /
• v.29 no.6
• /
• pp.736-744
• /
• 2007

We propose a fast macroblock (MB) mode prediction and decision algorithm based on temporal correlation for P-slices in the H.264/AVC video standard. There are eight block types for temporal decorrelation, including SKIP mode based on rate-distortion (RD) optimization. This scheme gives rise to exhaustive computations (search) in the coding procedure. To overcome this problem, a thresholding method for fast inter mode decision using a MB tracking scheme to find the most correlated block and RD cost of the correlated block is suggested for early stop of the inter mode determination. We propose a two-step inter mode candidate selection method using statistical analysis. In the first step, a mode is selected based on the mode information of the co-located MB from the previous frame. Then, an adaptive thresholding scheme is applied using the RD cost of the most correlated MB. Secondly, additional candidate modes are considered to determine the best mode of the initial candidate modes that does not satisfy the designed thresholding rule. Comparative analysis shows that a speed-up factor of up to 70.59% is obtained when compared with the full mode search method with a negligible bit increment and a minimal loss of image quality.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 1999.04a
• /
• pp.159-168
• /
• 1999

In seismic analysis, there are two main ways - uniform load method and dynamic analysis, dynamic analysis can be divided into response spectrum analysis and time history analysis. In case of which get the complexion of the vibration with 3-axis of coordinate direction in each mode of free vibration mode happened owing to complication of the shape, 3-dimensional dynamic analysis is recommended to perform as multi-mode spectral analysis in standard specification for highway bridge. The purpose of this study is to understand the dynamic behavior by performing multi-mode seismic analysis according to responses analysis and time history anal)'sis in using record of earthquake. In accordance with the criterion of seismic design as defined in standard specification for highway bridge by using modified records of the El Centre and Coyote Lake earthquake, response spectrum was constructed by using the tripartite logarithmic plot. The 3-span continuous space truss bridge was selected as model of numerical analysis. As the result performed time history analysis and analysis of response spectrum for the model of numerical analysis, the result of time history analysis was slightly larger than that of response spectrum analysis. This coincide with the tendency of the result came from the analysis when using a jagged response spectrum analysis, This coincide with the tendency of the result came from the analysis when using a jagged response spectrum for a single excitation. In the Process of performing these two analysis. response spectrum analysis is more effective than time history analysis in saving times in analyzing data.

• Proceedings of the IEEK Conference
• /
• 1998.10a
• /
• pp.131-134
• /
• 1998

This paper is describing an ADSL access network configuration by packet mode and analyzed the performance of this ADSL network. We are interesting in difference between ATM mode and packet mode concerning to the performance and service availability. So, this paper has described the characteristics of packet mode ADSL network.

• International Journal of Aeronautical and Space Sciences
• /
• v.14 no.2
• /
• pp.162-171
• /
• 2013

A general purpose aircraft mission performance analysis program has been developed. The program can be used in design mode or in analysis mode. Fuel weight for a given mission profile can be estimated when the design mode is chosen, while mission time or mission range for a given fuel can be estimated when the analysis mode is chosen. The mission analysis program is written with JAVA and includes GUI(Graphic User Interface) for users' conveniences. With a proper combination of databases for propulsion, aerodynamics and weight, the program can be configured to compute the performance of any type of aircraft. The program is validated by comparing its results with the results of a well known performance analysis program by ADD(Agency for Defense Development).

• Journal of KSNVE
• /
• v.7 no.5
• /
• pp.737-746
• /
• 1997

The substructure synthesis method is used for making it easy to analyze vibration systems generally in vibration field. In the past, this method has been to be used mainly because of shortage of computer memory and CPU time. But recently this method is used for analyzing complex structure or identifying the characteristics of systems precisely. The purpose of this study is to develop acoustic substructure synthesis method that can be applied to acoustic modal analysis of complex acoustic systems. Acoustic modal analysis method to be introduced here is a method that analyze acoustic natural mode shape of the complex acoustic system by the principle of CMS(component mode synthesis method). This paper describes the acoustic modal analysis of the acoustic finite element model of simple expansion pipe by acoustic substructure synthesis method. The resutls of acoustic modal analysis analyzed by Acoustic substructure synthesis method and the results by FEM(finite element method) shows good agreement.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.24 no.3
• /
• pp.207-214
• /
• 2019

In this study, discrete-time domain analysis is proposed to investigate the input current of a buck AC/DC light-emitting diode (LED) driver. The buck power factor correction converter can operate in both discontinuous conduction mode (DCM) and continuous conduction mode (CCM). Two discontinuous and two continuous conduction operating modes are possible depending on which event terminates the conduction of the main switch in a switching cycle. All four operating modes are considered in the discrete-time domain analysis. The peak current-mode control with slope compensation is used to design a low-cost AC/DC LED driver. A slope compensation design of the buck AC/DC LED driver is described on the basis of a discrete-time domain analysis. Experimental results are presented to confirm the usefulness of the proposed analysis.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 1992.03a
• /
• pp.83-102
• /
• 1992

As shear localization is observed in different deformation modes, an attempt is made to understand the conditions for shear localization in general deformation modes. Most emphasis in put upon the effects of pre-localization deformation mode on the onset of shear localization and all the other well-recognized effects of subtle constitutive features and imperfection sensitivity studied elsewhere are not investigated here. Rather, an approximate perturbation stability analysis is performed for simplified isotropic rigid-plastic solids subjected to general mode of homogeneous deformation. Shear localization is possible in any deformation mode if the material has strain softening. The incipient rate of shear localization and shear plane orientations are strongly dependent upon the pre-localization deformation mode. Significant strain softening is necessary for shear localization in homogeneous axisymmetric deformation modes while infinitesimal strain softening is necessary for shear localization in plane strain deformation mode. In any deformation mode, there are more than one shear plane orientation. Except for homogeneous axisymmetric deformation modes, there are two possible shear plane orientations with respect to the principal directions of stretching. Some well-known examples are discussed in the light of the current analysis.