• Journal of the Institute of Electronics Engineers of Korea SP
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• v.38 no.4
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• pp.335-343
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• 2001

The conventional wavelet-based fractal image coding has the disadvantage that the encoding takes a long time, since each range block finds the best domain in the image. In this Paper, we propose wavelet-based fractal image coding using SAS(Self Affine System) method and multi-scale factor. It consists of the range and domain blocks in DWT(discrete wavelet transform) region. Using SAS method, the proposed method is that the searching process of the domain block is not required, and the range block selects the domain which is relatively located the same position in the upper level. The proposed method can perform a fast encoding by reducing the computational complexity in the encoding process. In order to improve the disadvantage of SAS method which is reduced image qualify, the proposed method is improved image qualify using the different scale factors for each level. As a result, there is not influence on an image quality, the proposed method is enhanced the encoding time and compression ratio, and it is able to the progressive transmission.

• The Korean Journal of Applied Statistics
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• v.17 no.1
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• pp.153-164
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• 2004

In this study, we compare multivariate R-techniques in the up-to-date versions of SAS, SPSS, Minitab and S-plus. The direct input method by typing in command is considered for SAS, while the menu-driven method is considered for SPSS, Minitab and S-plus. Comparison was made in terms of input data format, input option, charts and outputs.

• Journal of the Korean Solar Energy Society
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• v.22 no.1
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• pp.67-72
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• 2002

Solar Air Systems (SAS) have unique advantages for space heating and tempering ventilation air. Air, unlike water, needs no protection against freezing nor are leaks damaging to the building structure or its contents. In contrast to glazed collector, unglazed steel solar collector may have higher efficiencies over glazed flat collector due to the absence of the glass. Therefore, the monitoring of SAS is so important to evaluate actual performance of SAS for right applications. This study is to provide a testing method with a movable test cell developed in KIER to evaluate the thermal performance of SAS based on international standard method ASHRAE 93-86, "Method of Testing to Determine the Thermal Performance of Solar Collectors". The monitoring tool used advanced technique LabVIEW 6i with portable notebook computer. Sample results have been obtained to access the performance of a reference and a target SAS module. The process and tool introduced here could be used to provide a performance verification data for future implementation study applications.

• Communications for Statistical Applications and Methods
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• v.10 no.2
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• pp.433-443
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• 2003

In this study, we provide a comparison of multivariate Q-techniques in the up-to-date versions of SAS, SPSS, Minitab and S-plus well known to those who study statistics. We can analyze data through the direct Input method(command) in SAS and use of menu method in SPSS, Minitab and S-plus. The analysis performance method is chosen by the high frequency of use. Widely we compare with each Q-techniques form according to input data, input option, statistical chart and statistical output.

• Journal of Korean Society for Quality Management
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• v.28 no.1
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• pp.95-104
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• 2000

There exist many computer algorithms to solve a system of nonlinear equations. But in case nonlinear equations are complex it is not easy to solve a system of nonlinear equations. In this paper we consider the method of using NLIN procedure in SAS/STAT to solve a system of nonlinear equations.

• The Journal of the Acoustical Society of Korea
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• v.40 no.6
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• pp.546-554
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• 2021

In the signal processing of synthetic aperture sonar, it is subject that the platform in which the sensor array is installed moves along the straight line path. In practical operation in underwater, however, the sensor platform will have trajectory disturbances, diverting from the line path. It causes phase errors in measured signals and then produces deteriorated SAS images. In this study, in order to develop towed SAS, as tools to remove the phase errors associated with the trajectory disturbances of the towfish, motion compensation technique using Redundant Phase Center (RPC) and also Phase Gradient Autofocus (PGA) method is investigated. The performances of these two approaches are examined by means of a simulation for SAS system having a sway disturbance.

• Korean Journal of Mathematics
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• v.16 no.4
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• pp.471-480
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• 2008

As students with low basic knowledge of mathematics increase, they have had difficulties in studying statistics theory class. By using recent students' characteristics which prefer seeing directly and checking to thinking logically, we try to change the teaching method into teaching in the computer lab(SAS program). We investigate whether changing the teaching method has effects on students' achievements and interests or not. The purpose of this study is to grope for a better teaching and develop mathematics education's satisfaction and qualification.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.38 no.4
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• pp.11-11
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• 2001

기존의 웨이브릿 기반 프랙탈 압축 방법은 전 영역에 대하여 최적의 정의역을 탐색하므로, 부호화 과정에서 많은 탐색시간이 소요되는 단점이 있다. 그래서 본 논문에서는 웨이브릿 변환영역에서 SAS(Self Affine System) 기법과 다중 스케일 인자를 이용한 웨이브릿 변환 기반 프랙탈 영상 압축 방법을 제안한다. 웨이브릿 기반 영역에서 정의역과 치역을 구성하고, 각각의 치역 블럭에 대해 모든 정의역 블럭을 탐색하는 것이 아니라, 정의역 탐색과정이 필요 없는 SAS 기법을 도입하여 공간적으로 같은 위치에 있는 상위 레벨 블록을 정의역으로 선택한다 그래서 부호화 과정에서 곱셈 계산량을 감소시켜 고속 부호화를 가능하게 한다. 그리고 SAS 기법의 단점인 화질이 떨어지는 단점을 개선하기 위해, 각 레벨별로 서로 다른 스케일 인자를 사 용하여 화질을 개선한다. 그 결과 화질에는 영향을 미치지 않고 부호화 시간과 압축률이 개선되고, 점진적 전송이 가능한 알고리듬을 제안한다.

• Proceedings of the KIPE Conference
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• 2019.11a
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• pp.200-201
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• 2019

Due to uncontrollability and non-repeatability of natural irradiation and temperature, the solar array simulator (SAS) is required to conduct the MPPT power processing experiments precisely. However, the nonlinearity of PV curve characteristic is a crucial task for the control of SAS. In the literature, this issue is addressed by many authors and various methods are proposed. However, stability analysis of SAS is not enough to evaluate the control performance. In this paper, the limitations of conventional SAS are studied according to the small signal model. By using the proposed approach, the performance of two different control method for SAS system are analyzed and compared.

• Clean Technology
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• v.16 no.2
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• pp.80-87
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• 2010

In this study, micro- and submicron particles of itraconazole, a poorly water-soluble antifungal drug, were prepared for improving its aqueous solubility using an ultrasound-assisted supercritical fluid technique, called SAS-EM. The SAS-EM process used in our experiments was different from the conventional SAS-EM in that the ultrasound was applied directly to the spray nozzle. The effect of the ultrasonic power, temperature, and solvent on the formation of itraconazole particles were investigated. Smaller particles were obtained through our SAS-EM process compared with the ASES process, and the mean particle size decreased as the ultrasonic power increased. Our experimental results confirmed that the ultrasound-assisted supercritical fluid process is an efficient method for producing ultrafine particles.