• Ocean and Polar Research
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• v.21 no.2
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• pp.87-97
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• 1999

To estimate absolute transports by advection in the southwestern East Sea (Japan Sea), an inverse method was applied to CTD data obtained in July 1993. The relative velocities are calculated using the thermal wind equation. The inverse model was formulated to obtain a reference velocity based on the mass conservation in each of four vertical layers within a region enclosed by hydrographic sections and the coastal boundary. The flow patterns in the surface layer are clockwise and anti-clockwise in the regions south and northwest of Ulleung Island, respectively, and a strong northward flow appears in between them. In the second layer, the flow fields are generally weak. The inverse calculation yields the southward flow along the coast, and this suggests that the subsurface low salinity water in the Ulleung Basin is supplied by the southward transport along the east coast of Korea.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.32 no.4
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• pp.136-144
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• 1983

In this paper, a new scheme of implicit MRAC is presented for single input single output discrete system. The MRAC can be applied to the nonminimum phase system, too. They have simple structure because the parameters of the controller are estimated directly by changing the plant output equation properly. In this scheme, the observation process is well seperated from the adaptation process, so the adaptation algorithm is derived from the exponentially weighted least square method which has fast convergence characteristics and can deal with the time varying plant. The consistency of the estimated parameter is proved. And it is also proved the whole system has the stabilizing property. The effectiveness of the algorithm and the structure is illustrated by the computer simulation of the model reference adaptive control for a third order plant. It is proposed how to select the selectable parameters in the adaptive control system from the simulation results.

• International Journal of Aeronautical and Space Sciences
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• v.3 no.1
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• pp.30-38
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• 2002

In multi-dimensional systems, various solution schemes for radiative transfer are suggested but the applicabilities and accuracies of these schemes have not yet fully tested due to the lack of reference solutions especially for nongray gases. In this paper we present some precise radiative transfer solutions for a black walled 3-dimensional cylindrical system filled with nongray gases having uniform temperature and concentration. The ray-tracing method with the $T_N$ quadrature set and the SNB model are used to obtain the radiative transfer solutions by the nongray gases. The solutions presented in this paper are proved to be quite accurate and can be regarded as the reference solutions for the radiative transfer by nongray gases.

• Journal of the Korea Institute of Military Science and Technology
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• v.10 no.3
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• pp.200-207
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• 2007

Single base propellant using a nitrate ester compound NC decomposes naturally during storage time. Therefore, the research for storage life extension is necessary to single base propellant. In this research, $CaCO_3$ inorganic stabilizer had been added into single base propellants up to 0.3%, and the accelerated aging test of the propellant was started. And then, with applying the Arrhenius equation, the storage life of the test of the propellant was contrasted with that of reference propellant. As a result, the storage life of the propellant containing $CaCO_3$ inorganic stabilizer was about twice longer than the reference propellant.

• Journal of the Korea Institute of Military Science and Technology
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• v.19 no.6
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• pp.712-720
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• 2016

The purpose of this study was to inspect ballistic match of copper bullet at 4 points by analyzing vertical deviation about shot group of the 5.56 mm common bullets and copper bullets. The 5.56 mm bullet with new copper core material was developed for mitigation of environmental pollution and harmfulness to human body. The results of this study are as follows; using the regression analysis, estimated reference value of ballistic match were 51.6 mm, 64.9 mm, 87.3 mm and 99.6 mm at 25 m, 100 m, 200 m and 250 m range respectively. When analyzing the shooting test data, alternative hypothesis(The vertical deviations are less than the reference value) was adopted as the result of analyzing data using t-test. And the values of data through tool(PRODAS) and standard trajectory equation meet requirements of estimated ballistic match respectively. In conclusion, the level of ballistic match of 5.56 mm copper bullets meets the estimated reference level through regression analysis at 4 points.

• Journal of The Korean Society of Agricultural Engineers
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• v.52 no.5
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• pp.1-9
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• 2010

Evapotranspiration (ET) is one of the basic components of the hydrologic cycle and is essential for estimating irrigation water requirements. In this study, artificial neural network (ANN) models for reference crop evapotranspiration ($ET_0$) estimation were developed on a monthly basis (May~October). The models were trained and tested for Suwon, Korea. Four climate factors, daily maximum temperature ($T_{max}$), daily minimum temperature ($T_{min}$), rainfall (R), and solar radiation (S) were used as the input parameters of the models. The target values of the models were calculated using Food and Agriculture Organization (FAO) Penman-Monteith equation. Future climate data were generated using LARS-WG (Long Ashton Research Station-Weather Generator), stochastic weather generator, based on HadCM3 (Hadley Centre Coupled Model, ver.3) A1B scenario. The evapotranspirations were 549.7 mm/yr in baseline period (1973-2008), 558.1 mm/yr in 2011-2030, 593.0 mm/yr in 2046-2065, and 641.1 mm/yr in 2080-2099. The results showed that the ANN models achieved good performances in estimating future reference crop evapotranspiration.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.2
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• pp.697-702
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• 2016

To control permanent magnet synchronous motors smoothly, it is important to know the exact parameter values of the stator resistance, various inductances, and the flux linkage of the permanent magnet. In practice, these parameters vary due to a variable operating point, temperature change, or a fault. This paper proposes a MRAS (Model Reference Adaptive System) based parameter estimator and adaptive control scheme. Owing to the non-linearity of the system equation with respect to these parameters, although many schemes proposed previously assumed that some parameters are known, all the parameters were assumed to be unknown. The simulation results revealed the effectiveness of the proposed algorithm.

• Progress in Superconductivity
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• v.3 no.2
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• pp.151-158
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• 2002

We developed a useful SQUID magnetometer for biomagnetic applications, magnetoencepha-logram(MEG) and magnetocardiogram(MCG), etc. The SQUIDs are based on Double Relaxation Oscillation SQUID(DROS). DROS consists of two SQUIDs(signal SQUID and reference SQUID) in series, and a relaxation circuit of an inductor and a resistor. Specially we used single reference junction instead of the reference SQUID. The SQUIDs are based on hysteretic $Nb/AlO_{x}$Nb junctions, fabricated by using a simple four level process. Because DROS magnetometer has large flux-to-voltage transfer coefficient, we can use simple flux-locked loop electronics fur SQUID operation. When the DROS magnetometer was operated inside a magnetically shielded room, its average magnetic field noise was about 3 (equation omitted) at 100 Hz. This noise level is low enough to measure biomagnetic fields. In this paper, we describe noise characteristics of DROS magnetometer, depending on the operation condition . .

• Journal of the Korean Society for Precision Engineering
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• v.22 no.7 s.172
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• pp.112-121
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• 2005

This paper is concerned with smooth trajectory generation of biped robot which has inverted pendulum type balancing weight. Genetic algorithm is used to generate the trajectory of the leg and balancing weight. Balancing trajectory can be determined by solving the second order differential equation under the condition that the reference ZMP (Zero moment point) is settled. Reference ZMP effect on gait pattern absolutely but the problem is how to determine the reference ZMP. Genetic algorithm can find optimal solution under the high order nonlinear situation. Optimal trajectory is generated when use genetic algorithm which has some genes and a fitness function. In this paper, minimization of balancing joints motion is used for the fitness function and set the weight factor of the two balancing joints at the fitness function. Inverted pendulum type balancing weight is very similar with human and this model can be used fur humanoid robot. Simulation results show ZMP trajectory and the walking experiment made on the real biped robot IWR-IV.

• Food Science and Biotechnology
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• v.18 no.1
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• pp.60-65
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• 2009

Near infrared reflectance spectroscopy (NIRS) was used as a rapid and non-destructive method to determine the protein content in intact and ground seeds of pea (Pisum sativum L.) germplasms grown in Korea. A total of 115 samples were scanned in the reflectance mode of a scanning monochromator at intact seed and flour condition, and the reference values for the protein content was measured by auto-Kjeldahl system. In the developed ground and intact NIRS equations for analysis of protein, the most accurate equation were obtained at 2, 8, 6, 1 math treatment conditions with standard normal variate and detrend scatter correction method and entire spectrum (400-2,500 nm) by using modified partial least squares regression (n=78). External validation (n=34) of these NIRS equations showed significant correlation between reference values and NIRS estimated values based on the standard error of prediction (SEP), $R^2$, and the ratio of standard deviation of reference data to SEP. Therefore, these ground and intact NIRS equations can be applicable and reliable for determination of protein content in pea seeds, and non-destructive NIRS method could be used as a mass analysis technique for selection of high protein pea in breeding program and for quality control in food industry.