• Journal of Korean Society of Steel Construction
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• v.13 no.3
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• pp.289-299
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• 2001

The purpose of this study was to analyze the characteristics of semi-igid behavior of the steel tubular column to H-beam connection reinforced with exterior square-plate diaphragms and to check the main parameters that affect this behavior. Steel tube connections without interior diaphragm and/or complicated exterior diaphragm show the considerable flexibility due to out of-plane deformation of tube flange. For the exact analysis well-reflected the effect of this flexibility on the overall frame performance. it need to find out the moment-rotation curve function that well trace the result of experiment in the whole region and the function should be simply transformed into an adequate form for the nonlinear analysis program. After collecting several test data same to the connection type considered. we carried out FEM analysis using ANSYS for the assumed beam-to-column connection developed from the simple tension test and the results are compared with experimental values. Based on the parametric study. we proposed the moment-relation curve function and performed the multiple-regression analysis procedure for three parameters consisting of this function with the main geometric parameter of this connection type.

• Journal of the Korea Computer Industry Society
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• v.7 no.4
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• pp.427-436
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• 2006

State-space method for the analysis of the dynamic characteristics of a body motion is set up as mathematical tool for the solution of differential equation by computer. Representation of a system is described as a simple form of matrix calculation and unique form of model is available for the linear or nonlinear, time variant or time invariant, mono variable or multi variable system etc. For the analysis of state-space method a complicated vector calculation is required, but this analysis can be simplified with the specific functions of a software package. Recently as the Graphical User Interface softwares are well-developed, then it is very simplified to execute the simulation of the dynamic characteristics for the state-space model with the interactive graphics treatment. The purpose of this study is to developed the simulator for the educational analysis of the dynamic characteristics of body motion, and for the analysis of the longitudinal dynamic characteristics of an aircraft that is primarily to design the simulator for the analysis of the transient response of an aircraft longitudinal stability.

• Computers and Concrete
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• v.12 no.2
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• pp.211-228
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• 2013

The structure analyzed in this paper has particular building style and special structural system. It is a rigid-connected twin-tower skyscraper with asymmetrical distribution of stiffness and masses in two towers. Because of the different stiffness between the north and the south towers, the torsion seismic vibration is significant. In this paper, in order to study the seismic response of the structure under both frequent low-intensity earthquakes as well as rare earthquakes at the levels of intensity 7, the analysis model is built and analyzed with NosaCAD. NosaCAD is an nonlinear structure analysis software based on second-development of AutoCAD with ObjectARX. It has convenient modeling function, high computational efficiency and diversity post-processing functions. The deformations, forces and damages of the structure are investigated based on the analysis. According to the analysis, there is no damage on the structure under frequent earthquakes, and the structure has sufficient capacity and ductility to resist rare earthquakes. Therefore the structure can reach the goal of no damage under frequent earthquakes and no collapse under rare earthquakes. The deformation of the structure is below the limit in Chinese code. The time sequence and distribution of damages on tubes are reasonable, which can dissipate some dynamic energy. At last, according to forces, load-carrying capacity and damage of elements, there are some suggestions on increasing the reinforcement in the core tube at base and in stiffened stories.

• The Journal of the Korea Contents Association
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• v.15 no.4
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• pp.479-489
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• 2015

The paradigm of communication is changing by the generalization of mobile computers and the extension of network service. In the mobile messenger communication, people are increasingly using character emoticons to substitute linear text. This means that the character emoticons are functioning as narrative characters so that they are becoming the nonlinear techno-code, which can substitute for the alphabet code. As Vil$\acute{e}$m Flusser said, the post-modern communication is arrived. In this kind of communication, storytelling with character emoticons are effective enough to tell various stories. In this point of view, this paper tries to prove the functions of character emoticons and suggests the classification of the character emoticon series. This paper also structures the post-modern communication model as a new paradigm of visual communication.

• The Korean Journal of Applied Statistics
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• v.29 no.3
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• pp.525-537
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• 2016

The paper considers a hybrid model to analyze and forecast time series data based on an empirical mode decomposition (EMD) that accommodates complex characteristics of time series such as nonstationarity and nonlinearity. We aggregate IMFs using the concept of cumulative energy to improve the interpretability of intrinsic mode functions (IMFs) from EMD. We forecast aggregated IMFs and residue with a hybrid model that combines the ARIMA model and an exponential smoothing method (ETS). The proposed method is applied to forecast KOSPI time series and is compared to traditional forecast models. Aggregated IMFs and residue provide a convenience to interpret the short, medium and long term dynamics of the KOSPI. It is also observed that the hybrid model with ARIMA and ETS is superior to traditional and other types of hybrid models.

• Journal of the Optical Society of Korea
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• v.15 no.4
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• pp.386-393
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• 2011

In this study, we report an effective k-domain linearization method with a pre-calibrated indexed look-up table. The method minimizes k-domain nonlinear characteristics of a swept source optical coherence tomography (SS-OCT) system by using two arrays, a sample position shift index and an intensity compensation array. Two arrays are generated from an interference pattern acquired by connecting a Fabry-Perot interferometer (FPI) and an optical spectrum analyzer (OSA) to the system. At real time imaging, the sample position is modified by location movement and intensity compensation with two arrays for linearity of wavenumber. As a result of evaluating point spread functions (PSFs), the signal to noise ratio (SNR) is increased by 9.7 dB. When applied to infrared (IR) sensing card imaging, the SNR is increased by 1.29 dB and the contrast noise ratio (CNR) value is increased by 1.44. The time required for the linearization and intensity compensation is 30 ms for a multi thread method using a central processing unit (CPU) compared to 0.8 ms for compute unified device architecture (CUDA) processing using a graphics processing unit (GPU). We verified that our linearization method is appropriate for applying real time imaging of SS-OCT.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.42 no.10
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• pp.884-892
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• 2014

In this paper, a meta model using neural network substituting for the simulator aerodynamic database is proposed to improve simulation fidelity near the critical flight area and real-time performance. It is shown that the accuracy of the meta model is relatively higher than the existing table lookup methods for arbitrary nonlinear database and the calculation speed is also improved for a specific F-16 maneuver simulation. The increase in the number of hidden nodes in the meta model for better accuracy of database representations causes a delay in function generation due to increased time required for computing exponential functions. In order to make up this drawback, we additionally study the fast exponential function method.

• Korean journal of applied entomology
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• v.56 no.1
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• pp.1-18
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• 2017

Temperature-dependent development model is an essential component for forecasting models of insect pests as well as for insect population models. This study reviewed the nonlinear models which explain the relationship between temperature and development rate of insects. In the present study, the types of models were classified largely into empirical and biophysical model, and the groups were subdivided into subgroups according to the similarity of mathematical equations or the connection with original idea. Empirical models that apply analytical functions describing the suitable shape of development curve were subdivided into multiple subgroups as Stinner-based types, Logan-based types, performance models and Beta distribution types. Biophysical models based on enzyme kinetic reaction were grouped as monophyletic group leading to Eyring-model, SM-model, SS-mode, and SSI-model. Finally, we described the historical development and characteristics of non-linear development models and discussed the availability of models.

• Proceeding of KASS Symposium
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• 2008.05a
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• pp.107-112
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• 2008

This paper investigates the variation of post-buckling behaviours of 2-dimensional shallow arch type truss after sizing optimization. The mathematical programming technique is used to produce the optimum member size of 2D arch truss against a central point load. Total weight of structure is considered as the objective function to be minimized and the displacement occurred at loading point and member stresses of truss are used as the constraint functions. The finite difference method is used to calculate the design sensitivity of objective function with respect to design variables. The postbuckling analysis carried out by using the geometrically nonlinear finite element analysis code ISADO-GN. It is found to be that there is a huge change of post-buckling behaviour between the initial structure and optimum structure. Numerical results can be used as useful information for future research of large spatial structures.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.41 no.6
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• pp.33-41
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• 2004

This paper proposes a color matching 3D look-up table simplifying the complex color matching procedure between a monitor and a mobile display device. In other to perform color matching, it is necessary to process color of image in the device independent color space like CIEXYZ or CIELAB. To obtain the data of the device independent color space from that of the device dependent RGB color space, we must perform display characterizations. LCD characterization error using S-curve model is larger than tolerance error since LCD is more nonlinear than CRT. This paper improves the S-curve model to have smaller characterization error than tolerance error using the electro-optical transfer functions of X, Y, and Z value. We obtained images having higher color fidelity on mobile display devices through color matching experiments between monitor and mobile display devices. As a result of this experiments, we concluded that the color matching look-up table with 64(4${\times}$4${\times}$4) is the smallest size allowing characterization error to be acceptable.