• Proceedings of the KIEE Conference
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• 1996.07b
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• pp.990-992
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• 1996

The design of I/O scaling factors for fuzzy controller system is proposed in this paper. The proposed method is for nonlinear input scaling factor and variable output scaling factor. The fuzzy controller is evaluated by computer simulation on the 1st order process and 2nd order process. Simulation results showed robust characteristics for variable reference signal.

• Earthquakes and Structures
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• v.5 no.2
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• pp.129-142
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• 2013

Linear and nonlinear time history analyses have been becoming more common in seismic analysis and design of structures with advances in computer technology and earthquake engineering. One of the most important issues for such analyses is the selection of appropriate acceleration time histories and matching these histories to a code design acceleration spectrum. In literature, there are three sources of acceleration time histories: artificial records, synthetic records obtained from seismological models and accelerograms recorded in real earthquakes. Because of the increase of the number of strong ground motion database, using and scaling real earthquake records for seismic analysis has been becoming one of the most popular research issues in earthquake engineering. In general, two methods are used for scaling actual earthquake records: scaling in time domain and frequency domain. The objective of this study is twofold: the first is to discuss and summarize basic methodologies and criteria for selecting and scaling ground motion time histories. The second is to analyze scaling results of time domain method according to ASCE 7-05 and Eurocode 8 (1998-1:2004) criteria. Differences between time domain method and frequency domain method are mentioned briefly. The time domain scaling procedure is utilized to scale the available real records obtained from near fault motions and far fault motions to match the proposed elastic design acceleration spectrum given in the Eurocode 8. Why the time domain method is preferred in this study is stated. The best fitted ground motion time histories are selected and these histories are analyzed according to Eurocode 8 (1998-1:2004) and ASCE 7-05 criteria. Also, characteristics of both near fault ground motions and far fault ground motions are presented by the help of figures. Hence, we can compare the effects of near fault ground motions on structures with far fault ground motions' effects.

• Science of Emotion and Sensibility
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• v.8 no.4
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• pp.415-422
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• 2005

The purpose of the present study was to investigate the differences of nonlinear characteristics of electroencephalogram (EEG) depending on different sensitivities of behavioral activation system (BAS) and behavioral inhibition system (BIS) of young and elderly groups. The EEGs from Fpl and Fp2 electrodes were recorded during resting condition. The young and elderly groups consisted of 19 and 31 healthy right-handed volunteers, respectively. We estimated 1/f scaling exponent which reflects the nonlinear dynamical complexity of EEG. As results, we found the differences of 1/f scaling exponent between young ant elderly BAS sensitive groups. The 1/f scaling exponent of young BAS sensitive group showed significantly higher values than those of elderly BAS sensitive group at the left prefrontal area (Fpl). The young BAS sensitive group had also a tendency to higher 1/f scaling exponent at the right prefrontal area (Fp2). Decrease of the 1/f scaling exponent indicates the increase of complexity and the decrease of the amount of information related to the statistical distribution. Therefore, the elderly BAS sensitive group has higher complexity than young BAS sensitive group, though they were all classified as BAS sensitive group by BAS/BIS scale. Our results suggest the possibility of correlation between BAS sensitivity an4 age.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.34 no.2
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• pp.60-67
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• 2011

Since the non-metric Multidimensional scaling (nMDS), a data visualization technique, provides with insights about engineering, economic, and scientific applications, it is widely used for analyzing large non-metric multidimensional data sets. The nMDS requires a fitness function to measure fit of the proximity data by the distances among n objects. Most commonly used fitness functions are nonlinear and have a difficulty to find a good configuration. In this paper, we propose a new fitness function, an absolute value type, and show its advantages.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.2562-2567
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• 2005

This paper suggests a new method discretization of nonlinear system using Taylor series expansion and zero-order hold assumption. This method is applied into the sampled-data representation of a nonlinear system with input time delay. Additionally, the delayed input is time varying and its amplitude is bounded. The maximum time-delayed input is assumed to be two sampling periods. Them mathematical expressions of the discretization method are presented and the ability of the algorithm is tested for some of the examples. And 'hybrid' discretization scheme that result from a combination of the ‘scaling and squaring' technique with the Taylor method are also proposed, especially under condition of very low sampling rates. The computer simulation proves the proposed algorithm discretized the nonlinear system with the variable time-delayed input accurately.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.8 no.2
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• pp.7-13
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• 2004

A Conjugate Gradient (CG) algorithm for unconstrained minimization is proposed which is invariant to a nonlinear scaling of a strictly convex quadratic function and which generates mutually conjugate directions for extended quadratic functions. It is derived for inexact line searches and is designed for the minimization of general nonlinear functions. It compares favorably in numerical tests with the original Dixon algorithm on which the new algorithm is based.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2011.04a
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• pp.278-281
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• 2011

The global coordinates generated from Isomap algorithm provide a simple way to analyze and manipulate high dimensional observations in terms of their intrinsic nonlinear degrees of freedom. Thus, Isomap can find globally meaningful coordinates and nonlinear structure of complex data sets, while neither principal component analysis (PCA) nor multidimensional scaling (MDS) are successful in many cases. It is demonstrated that the adapted Isomap algorithm successfully enhances the quality of pattern classification for damage identification in various numerical examples.

• Bulletin of the Korean Chemical Society
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• v.7 no.4
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• pp.283-288
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• 1986

A nonlinear analysis is presented for the treatment of fluctuations near the critical point in the presence of diffusion in the Schlogl models. The two time scaling method is used to obtain an evolution equation for the amplitude of fluctuations. It is shown that the fluctuations decay to zero in the stable region and they are enhanced to a finite value as time goes to infinity in the unstable region.

• Journal of the Korean Geotechnical Society
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• v.23 no.3
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• pp.141-147
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• 2007

Various approaches have been developed for the dynamic response analysis of piles. In one of the approaches, the soil-pile interaction is approximated by using parallel nonlinear springs, namely the p-y curves. Currently available p-y curve recommendations are based on static and cyclic lateral load tests. Other researchers have attempted to extend the p-y curves by incorporating the effects of liquefaction on soil-pile interaction and derived scaling factors of p-y curves to account fur the liquefaction. However, opinions on the scaling factors vary. In this study, the sealing factors, which reflect the variation of the elastic moduli of surrounding soils, were established combining the relationship between excess pore pressures and the natural frequencies of a soil-pile system obtained from Ig shaking table tests and the relationship between the elastic moduli of surrounding soils and the natural frequencies of a soil-pile system obtained from numerical analyses. As a result, the scaling factors were presented in an exponential function.

• Korean Journal of Agricultural and Forest Meteorology
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• v.7 no.1
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• pp.4-14
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• 2005

CarboKorea and HydroKorea are the domestic projects aiming to improve our understanding of carbon and water cycles in a typical Korean forest located in a complex terrain with a watershed connected to large rivers. The ultimate goal is to provide a nowcasting of these cycles for the whole Peninsula. The basic strategy to achieve such goal is through the inter- and multi-disciplinary studies that synthesize the in-situ field observation, modeling and remote sensing technology. The challenge is the fact that natural ecosystems are nonlinear and heterogeneous with a wide range of spatio-temporal scales causing the variations of mass and energy exchanges from a leaf to landscape scales. Our paradigm now shifts from temporal variation at a point to spatial patterns and from spatial homogeneity to complexity of water and carbon at multiple scales. Yet, a large portion of our knowledge about land-atmosphere interactions has been established based on tower observations, indicating that the development of scaling logics holds the key to the success of CarboKorea and HydroKorea. Here, we review the pioneering work of FIFE (First ISLSCP Field Experiment) on scaling issues in a temperate grassland and discuss the lessons from it for the application to Gwangneung forest site.