• 한국한의학연구원논문집
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• 제12권2호통권17호
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• pp.85-92
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• 2006

Pulse is one of the basic diagnostic information of TKM(Traditional Korean Medicine). To quantify and standardize pulse diagnosis, we had collected an amount of clinical data from May 2005 by using newly developed pulse analyzer. But there were many noises in pulse wave according to measuring method, environment, operator and condition of patient. So some data can’t be included for analyzing diagnosis. To reduce noises from measuring pulse and to collect reliable pulse wave data, we made the process map of measuring method and applied six sigma project. With this we can improved the method of measuring pulse wave in collecting clinical data. The project follows a disciplined process of five macro phases: define, measure, analyze, improve and control (DMAIC). A process map and C-E diagram are used to identify process input and output variables. The major input variables are selected by using C&E matrix, and process map is developed by analyzing input variables. And the optimum process conditions are going to be controled to avoid in increasing loss of collecting pulse wave data.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.336-341
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• 2004

In this paper, a hybrid stabilization approach involving both passivity observer/passivity controller and wave variables is addressed to stabilize a teleoperation system with fixed time delay. To guarantee the stability of master or slave side, passivity observer/passivity controller are applied. But, passivity observer/passivity controller cannot deal with communication delay, and thus even small communication delay cause the system to be unstable. To cope with this problem, wave variables are additionally employed to have robustness to fixed communication delays. To show the validity of our proposed approach, several computer simulation results are illustrated.

• 대한조선학회논문집
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• 제43권1호
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• pp.96-102
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• 2006

In this study, an optimization routine with genetic algorithms is coupled for the selection of free variables for the production of a control signal for the motion of wave board in the numerical wave tank. An excitation function for the controlling of the wave board is formulated on basis of amplitude modulation for the generation of nonlinear wave packets. The found variables by the optimization serve for the determination of wave board motion both with the computation and with the experiment. The breaking criterion of the water waves is implemented as boundary condition for the optimization procedure. With the analysis of the time registration on the local position in the wave tank the optimization routine is accomplished until the given design wave with defined surface elevation is found. Water surface elevation and associated fields of velocity and pressure are numerically computed.

• International Journal of Aeronautical and Space Sciences
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• 제7권2호
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• pp.26-32
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• 2006

This paper targets a direct and quantitative prediction of characteristics of unstable waves in a combustion chamber, which employs the governing equations derived in terms of amplification factors of flow variables. A freshly formulated nonlinear acoustic equation is obtained and the analysis of unsteady waves in a rocket engine is attempted. In the present formalism, perturbation method decomposes the variables into time-averaged part that can be obtained easily and accurately and time-varying part which is assumed to be harmonic. Excluding the use of conventional spatially sinusoidal eigenfunctions, a direct numerical solution of wave equation replaces the initial spatial distribution of standing waves and forms the nonlinear space-averaged terms. Amplification factor is also calculated independently by the time rate of changes of fluctuating variables, and is no longer an explicit function for compulsory representation. Employing only the numerical computation, major assumptions inevitably inherent, and in erroneous manner, in up to date analytical methods could be avoided. With two definitions of amplification factor, 1-D stable wave and 3-D unstable wave are examined, and clearly demonstrated the potentiality of a suggested theoretical-numerical method of combustion instability.

• Journal of applied mathematics & informatics
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• 제13권1_2호
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• pp.53-65
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• 2003

Here we present a study of small-amplitude, shallow water waves on sloping beds. The beds considered in this analysis are linear and quadratic in nature. First we start with stating the relevant governing equations and boundary conditions for the theory of water waves. Once the complete prescription of the water-wave problem is available based on some assumptions (like inviscid, irrotational flow), we normalize it by introducing a suitable set of non-dimensional variables and then we scale the variables with respect to the amplitude parameter. This helps us to characterize the various types of approximation. In the process, a summary of equations that represent different approximations of the water-wave problem is stated. All the relevant equations are presented in rectangular Cartesian coordinates. Then we derive the equations and boundary conditions for small-amplitude and shallow water waves. Two specific types of bed are considered for our calculations. One is a bed with constant slope and the other bed has a quadratic form of surface. These are solved by using separation of variables method.

• Journal of Mechanical Science and Technology
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• 제19권8호
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• pp.1682-1691
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• 2005

Direct numerical simulation database of an axial turbulent boundary layer is used to compute frequency and wave number spectra of the wall shear-stress fluctuations in a low-Reynolds number axial turbulent boundary layer. One-dimensional and two-dimensional power spectra of flow variables are calculated and compared. At low wave numbers and frequencies, the power of streamwise shear stress is larger than that of spanwise shear stress, while the powers of both stresses are almost the same at high wave numbers and frequencies. The frequency/streamwise wave number spectra of the wall flow variables show that large-scale fluctuations to the rms value is largest for the stream wise shear stress, while that of small-scale fluctuations to the rms value is largest for pressure. In the two-point auto-correlations, negative correlation occurs in streamwise separations for pressure, and in span wise correlation for both shear stresses.

• 제어로봇시스템학회논문지
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• 제17권3호
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• pp.258-263
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• 2011

In the bilateral tele-operation system, time delay may be a critical problem. Even if system modeling error or time delay occurs, when applied to wave transformation system, the system's stability can be achieved. Using the characteristic b which is an important parameter of wave transformation, the system can display robust performance for time delay. However, since assuming and that the time delay was fixed developing a theory, a stability cannot be guaranteed about the time-varying delay. Therefore, In the paper, Therefore, in this paper, we studied for the method that controls this by applying the fuzzy algorithm which surveyed the timevarying delay characteristics and can adjust the b according to it adaptively.

• 제어로봇시스템학회논문지
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• 제9권8호
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• pp.600-609
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• 2003

A hybrid stabilization approach involving both Passivity Observer/passivity Controller and wave variables is addressed to stabilize the teleoperation system with time delay. To guarantee the stability of master or slave side, Passivity Observer and Passivity Controller are applied. But Passivity Observer and Passivity Controller technique cannot deal with communication delay and even small communication delay cause the system to be unstable. To cope with this problem, wave variables are additionally employed to have robustness to arbitrary delays. To show the validity of our proposed approach, several computer simulation results are illustrated.

• 설비공학논문집
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• 제15권11호
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• pp.895-901
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• 2003

Direct numerical simulation database of an axial turbulent boundary layer is used to compute frequency and wave number spectra of the wall shear-stress fluctuations in a low-Reynolds number axial turbulent boundary layer. One-dimensional and two-dimensional power spectra of flow variables are calculated and compared. At low wave numbers and frequencies, the power of streamwise shear stress is larger than that of spanwise shear stress, while the powers of both stresses are almost the same at high wave numbers and frequencies. The frequency/streamwise wave number spectra of the wall flow variables show that large-scale fluctuations to the ms value is largest for the streamwise shear stress, while that of small-scale fluctuations to the rms value is largest for pressure. In the two-point auto-correlations, negative correlation occurs in streamwise separations for pressure and spanwise shear stress, and in spanwise correlation for both shear stresses.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2002년도 Proceedings of International Symposium on Remote Sensing
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• pp.429-434
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• 2002

The Synthetic Aperture Radar (SAR) data are considered to contain the greatest amount of information among various microwave techniques developed for measuring ocean variables from aircraft or satellites. They have the potential of measuring wavelength, wave direction and wave height of the ocean waves. But, it is difficult to retrieve significant ocean wave heights and surface current from conventional SAR data, since the imaging mechanism of ocean waves by a SAR is determined by the three basic modulation processes arise through the tilt modulation, hydrodynamic modulation and velocity bunching which are poorly known functions. Along-Track Interferometric (ATI) SAR systems can directly detect the Doppler shift associated with each pixel of a SAR image and have been used to estimate wave fields and surface currents. However, the Doppler shift is not simply proportional to the component of the mean surface current. It includes also contributions associated with the phase velocity of the Brags waves and orbital motions of all ocean waves that are longer than Brags waves. In this paper, we have developed a new method for extracting the surface current vector using multiple-frequency (L- & C-band) ATI SAR data, and have generated surface wave height information.