• Journal of the Korean Data and Information Science Society
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• 제13권2호
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• pp.77-85
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• 2002

The statistical testing methods have been widely recognized to determine the plain and cipher texts. In fact, the randomness for a sequence from an encryption algorithm is necessary to guarantee security and reliance of cipher algorithm. Thus, the statistical randomness tests are used to discover cipher text. In this paper, we would provide the critical value for an approximate entropy test by estimating the nonlinear regression equation when the number of sequence and the level of significance are given. Thus, we can discern plan and cipher text for real problem with given number of sequence and the level of significance. Also, we confirm the fitness of the estimated critical values from the rate of success for plain or cipher text.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2001년도 가을 학술발표회 논문집
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• pp.257-262
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• 2001

There are only a few tests to ensure concrete quality before placing in domestic situ; One is slump test for workability, the other is air content test for durability, the concrete compressive strength which is one of important factors to influence on concrete Quality has been tested after 28 days placing. Methods on early judgement of concrete strength have been introduced for concrete quality management, but such methods are time consuming, expensive, and required special expertise. Therefore, these have difficulty in situ application for concrete management. This study aimed at reviewing application of estimated equation of compressive strength as means for ready-mixed concrete, making an estimated equation which enables to estimate 28 days compressive strength by using regression formula analysis on basis of mixing designs of ready mixed concrete and results of compressive strength.

• 한국기계연구소 소보
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• 통권10호
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• pp.35-48
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• 1983

When the hydrodynamic coefficients of the ship maneuvering equation are estimated by captive model test, it is difficult to take account of the scale effect between model and full scale ship. This scale effect problem can be overcome by processing the sea trial data with system identification. Extended Kalman filter is used as a system identification technique for the modification of the simulation equation as well as the estimation of hydrodynamic coefficients. The phenomena of simultaneous drifting of linear coefficients occur. It is confirmed that two coefficients in each pair-($Y_v$', $Y_r$' -m' u'), ($N_v$', $N_r$' )-are simultaneously drifting and all 4 coefficients are simultaneously drifting together. Particularly simultaneous drifting of 2 coefficients in each pair is more significant. It is also shown that the simultaneous drifting of 4 coefficients can be reduced by choosing the input data which have the random v'/r' curve and 4 coefficients are estimated within 2-4% error, which may be noise level. So, it is recommended to operate the rudder randomly in sea trial or model test for the application of system identification technique.

• Food Science and Biotechnology
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• 제14권2호
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• pp.301-303
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• 2005

State diagram of highly concentrated branched oligosaccharides (HBOS) was constructed to better understand phase behavior of mixtures with different size of oligosaccharides. It showed dramatic plasticizing effect on glass transition, which was successfully described based on Couchman-Karasz equation model. $T_g$' estimated from state diagram corresponded well with previous empirical data measured by maximum ice formation through isothermal holding (annealing) process. Estimated $T_g$' and $C_g$' values were $-36.3^{\circ}C$ and 79.99%, respectively. $T_g$' value of HBOS was approximately $10^{\circ}C$ higher than that of sucrose, while $C_g$' value was similar to those of general carbohydrate materials, which could be useful for applications in frozen system.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2008년도 International Symposium on Remote Sensing
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• pp.53-56
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• 2008

Generally, the quality of satellite images is expressed by GSD (Ground Sample Distance), MTF (Modulation Transfer Function) and SNR (Signal to Noise Ratio). However, these factors are technology-oriented and do not explain interpretability of satellite images. We need a standardized index which shows standard of interpretability. In this study, we estimated NIIRS (National Imagery Interpretability Rating Scale) through the GIQE (General Image Quality Equation) which is able to judge image interpretability with the standardized index. Traditionally, NIIRS has been determined manually by specialized image analysts. We used the GIQE in order to reduce inefficiency and high costs cause by manual interpretation and to produce accurate NIIRS. For monitoring image degradation, we estimated GIQE physical parameters from image analysis and carried out time series analysis about the quality of the KOMPSAT-1 images. On all of the tests, we were able to identify the image degradation due to the changing time. This indicates that NIIRS derived from GIQE will be used for image degradation indicator.

• 한국안전학회지
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• 제15권4호
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• pp.88-94
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• 2000

The adsorption characteristics of Tharonil on granular activated carbon were experimentally investigated in an adsorber and in a packed column. It was estabilished that the adsorption equilibrium of Tharonil on granular activated carbon was more successfully fitted by Freundlich isotherm equation than Langmuir isotherm equation in the concentration range from 1 to 1000 mg/1. Intraparticle diffusivities (pore and surface diffusivity) of Tharonil were estimated by the concentration-time curve and adsorption isotherm. The estimated values of pore diffusivity and surface diffusivity are $6.70{\times}10^{-6}$ and $2.0{\times}10^{-9}cm^2/s$, respectively. From comparison of intraparticle diffusivities, it was found that surface diffusion was the limiting step for adsorption rate. The break time and breakthrough curve predicted by constant pattern-linear driving force model were shown to agree with the experimental results.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2008년도 춘계학술대회논문집
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• pp.576-579
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• 2008

Electrical impedance(EIT) for the multi-phase flow visualization is an imaging modality in which the resistivity distribution of the unknown object is estimated based on the known sets of injected currents and measured voltages on the surface of the object. In this paper, an EIT reconstruction algorithm based on the extended Kalman filter(EKF) is proposed. The EIT reconstruction problem is formulated as a dynamic model which is composed of the state equation and the observation equation, and the unknown resistivity distribution is estimated recursively with the aid of the EKF. To verify the reconstruction performance of the proposed algorithm, experiments with simulated multi-phase flow are performed.

• Journal of Ship and Ocean Technology
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• 제7권3호
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• pp.56-65
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• 2003

The hull monitoring systems of container ships with four long-base gages give enough information for identifying the hull girder loads such as bending and torsional moments. But such a load-identification for container ships has not been known. In this paper, a load-identification method is suggested in terms of a linear matrix equation that the measured strain vector equals to the multiplication of the transformation matrix and the desired strain component vector. The equation is proved to be mathematically complete by the property of positive-definite determinant of the transformation matrix. The method is applied to a hull stress monitoring system for 8100TED container ship during sea trial, and the estimated external loads illustrate reasonable results in comparison with the pre-estimated results. This moment decomposition concept has also been tested in real operation conditions. The typical phenomena over the Suez Canal illustrated very suitable results comparing with the physical understandings. Henceforth, one can effectively use the proposed concept to monitor the hull girder loads such as bending and torsional moments.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제54권2호
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• pp.71-80
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• 2005

This paper presents the position sensorless vector control of a cylindrical permanent magnet synchronous motor(PMSM) in the field weakening region. The position sensorless algorithm using an instantaneous reactive power of the PMSM is proposed. An instantaneous reactive power can be obtained from the vector product of rotor currents and back emf of the PMSM. Back emf includes the information of rotor speed. So the estimated speed can be yielded from the voltage equation of the PMSM. In other words, the estimated speed is compensated by using an instantaneous reactive power. To extend the speed range of the PMSM in the constant horsepower region, the field weakening control is applied. The proposed algorithm is not affected by mechanical motor parameters because the mechanical equation is not used. The effectiveness of the proposed algorithm is verified by the experimental results.

• 대한산업공학회지
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• 제42권3호
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• pp.165-172
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• 2016

The purpose of this study is to investigate the ergonomic verification of suitability of the 4-wheeled hand cart to prevent musculoskeletal problems in the firing test range. Because of the increasing amount of firing test, the needs to develop a projectile transferring device such as 4-wheeled hand cart has been increased. For the 4-wheeled hand cart, the lifting and carrying activity in the manual handling method were transformed to pushing activity. The risk of low back pain for lifting and carrying the projectile by manual was estimated by NLE and 3D SSPP. On the other hand, the risk for pushing the 4-wheeled hand cart was estimated by psychophysical and biomechanical method such as Mital's equation, Snook's table and 3D SSPP. It was shown that the 4-wheeled hand cart reduced the risk of low back pain drastically with higher efficiency and design compatibility.