• 한국신재생에너지학회:학술대회논문집
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• 2011.11a
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• pp.41.2-41.2
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• 2011

NREL NWTC Deside codes are analyzed and introduced to develop the system performance simulation program for wind turbine generator systems. In this paper, The AirfoilPrep generating the airfoil data, the IECWind generating hub-height wind data with extreme condition following IEC 61400-1, the TurbSim generating stochastic full-field turbulent wind data, the PreComp calculating structural and dynamic properties of composite blade and the BModes making mode shapes of blade and tower are explained respectively.

• 한국신재생에너지학회:학술대회논문집
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• 2011.11a
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• pp.42.1-42.1
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• 2011

NREL NWTC Deside codes are analyzed and introduced to develop the system performance simulation program for wind turbine generator systems. In this paper, The FAST performing multi-body and flexible body dynamics, control and the AeroDyn calculating aerodynamic forces with airfoil data and wind data are explained. Furthermore, initialization and process for transfer of aerodynamic force between AeroDyn and FAST at each time step are also introduced.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1997.10a
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• pp.254-261
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• 1997

In desingin plate bridges, the width-thickness ratio of flanges and webs are proportioned in such that the premature local buckling of flanges and webs prior to achievement of the full strength of plate-girders must be prevented. It is the common practive in most design codes that the flange local buckling strength and the web bend buckling strength are separately computed. In most practical plate girders, however, the flange buckles simultaneously when web bend-buckling occurs, vice versa. The primary purpose of the present study is to investigate the phenomenon, which may be called flange-web interactive buckling. Using the eight-node shell element available in the commercial multi-purpose program ABAQUS, the phenomenon was quantitatively investigated. Also presented are the effects of various factors such as the ratio of flange slenderness ratio to the web slenderness ratio, the ratio of flange width to the web depth, and the longitudinal stiffeners. A series of comparative studies with various design codes show that the present study provides more accurate and effective design basis in proportioning the flanges and webs.

• Proceedings of the IEEK Conference
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• 2002.07c
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• pp.2071-2074
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• 2002

This paper introduces an encoder design method of Turbo TCM (Trellis Coded Modulation) with symbol puncturing. TTCM consists of two simple trellis codes in parallel and modulator. To obtain an good encoder, we calculate the free distance by the assumption that the punctured symbol is transmitted from the subset that consist of signals with the same systematic bit at random. We develop a search program to find the component encoder which maximize the free distance. Especially, for 8-PSK with code rate 2/3, we search for the component codes. We find a new encoder which has better BER performance than that of Robertson′s encoder. We verify the results through the simulation."

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2003.10a
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• pp.71-78
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• 2003

In this study, the impact analysis for the steel fender system that designed for protection of collision between vessel and bridge was peformed. The size of objective collision vessel assumed as 3000 dead weight tonnage(DWT). The impact forces and the impact energies were estimated by formulas of several design codes, and the steel fender system was designed based on the estimated forces and energy. The bow of objective vessel was modeled as rigid body, and bridge substructure was modeled as fixed support. Since, the impact analysis have the dynamic nonlinear features, such as, material nonlinear, large deformation and contact, explicit structural analysis program was used. The analysis results presented that the impact forces formulas in codes have the sufficient conservativeness.

• Journal of Electrical Engineering and Technology
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• v.6 no.5
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• pp.723-730
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• 2011

The GPS modernization program offered a new civil signal on the L2 band, and the first modernized GPS Block IIR satellite was launched in September 2005. Currently, eight GPS Block IIRM satellites and two Block IIF satellites transmit L2C signal. The L2C signal contains two codes of CM and CL that are much longer than the L1 C/A code. Thus, the acquisition of the CM and CL codes takes more time compared with that of L1 C/A code. Under the assumption that the L2C signal is strong enough for detection, this paper suggests rapid acquisition methods for the GPS L2C signals for software receivers and compares its performance with that of other methods.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.18 no.2
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• pp.97-105
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• 2008

The various mutations of the malicious codes are fast generated on the network. Also the behaviors of them become intelligent and the damage becomes larger step by step. In this paper, we suggest the method to select the useful measures for the detection of the codes. The method has the advantage of shortening the detection time by using header data without payloads and uses connection data that are composed of TCP/IP packets, and much information of each connection makes use of the measures. A naive estimator is applied to the probability distribution that are calculated by the histogram estimator to select the specific measures among 80 measures for the useful detection. The useful measures are then selected by using relative entropy. This method solves the problem that is to misclassify the measure values. We present the usefulness of the proposed method through the result of the detection experiment using the detection patterns based on the selected measures.

• Journal of computational fluids engineering
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• v.8 no.1
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• pp.16-22
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• 2003

The present study introduces an architecture for performing efficient numerical analysis by using the Internet and three reconstructing methods of existing numerical analysis codes were presented in order to utilize the architecture. These methods were implemented into a computational fluid dynamics program for solving two-dimensional transient flow problems with free surface. The program was reconstructed with Java technologies and compared with the original one. This study will be a preparation for numerical analysis to participate in web services for engineering.

• Nuclear Engineering and Technology
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• v.46 no.5
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• pp.719-724
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• 2014

During the development process of a thermal-hydraulic system code, a non-regression test (NRT) must be performed repeatedly in order to prevent software regression. The NRT process, however, is time-consuming and labor-intensive. Thus, automation of this process is an ideal solution. In this study, we have developed a program to support an efficient NRT for the SPACE code and demonstrated its usability. This results in a high degree of efficiency for code development. The program was developed using the Visual Basic for Applications and designed so that it can be easily customized for the NRT of other computer codes.

• Journal of the Korea Society of Computer and Information
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• v.10 no.3 s.35
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• pp.75-88
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• 2005

This paper proposes a method to ensure security attacks caused by insertion of malicious codes in a real-time control system that can be accessed through networks. The proposed technique is for dynamically upgradable real-time software through networks and based on a static program analysis technique to detect the malicious uses of memory access statements. Validation results are shown using a remotely upgradable real-time control system equipped with a modified compiler where the proposed security technique is applied.