• Steel and Composite Structures
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• v.18 no.3
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• pp.711-737
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• 2015

Steel Plate Shear Walls (SPSWs) have been accepted widely as an effective lateral load resisting system. For seismic performance evaluation of a multi-story building with SPSWs, detailed finite element models or a strip model can be used to represent the SPSW components. However, such models often require significant effort for tall or medium height buildings. In order to simplify the analysis process, discrete elements for the framing members can be used. This paper presents development of a simplified equivalent braced model to study the behavior of the SPSWs. The proposed model is expected to facilitate a simplification to the structural modeling of large buildings with SPSWs in order to evaluate the seismic performance using regular structural analysis tools. It is observed that the proposed model can capture the global behavior of the structures quite accurately and potentially aid in the performance-based seismic design of SPSW buildings.

• Structural Engineering and Mechanics
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• v.38 no.2
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• pp.231-247
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• 2011

This study introduces a new load increment method for the ductile reinforced concrete (RC) frame structures by including strain-hardening effects. The proposed method is a nonlinear static analysis technique employed for RC frame structures subjected to constant gravity loads and monotonically increasing lateral loads. The material nonlinearity in RC structural elements is considered by adopting plastic hinge concept which is extended by including the strain hardening as well as interaction between bending moment and axial force. Geometric non-linearity, known as second order effect, is implemented to the method as well.

• Proceedings of the KIEE Conference
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• 1993.07a
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• pp.529-533
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• 1993

Recently, the analysis of power systems is transfering from analytical techniques to simulation because it is difficult to analyze accurately the phenomena occured in complicated and huge power systems. Digital computers are used popularly to analyze the phenomena of power systems. But real-time simulators were used due to the limitation of digital computer - real time analysis, non-linearity and so on - and rapid development of digital technologies. In this paper, we discuss the advanced foreign power system simulators and the conceptual designs for the KEPCO power system simulator have been drawn for the domestic development.

• Proceedings of the KIEE Conference
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• summer
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• pp.1025-1027
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• 2004

Recently, the Single phase SRM has been researched and developed in many appliances with various types. This paper presents a theoretical representation of the phase inductance of a single phase SRM, as function of position and current, taking into account the non-linearity of the magnetic circuit. The method is based on the Fourier series expansion. the theoretical expressions for the calculation of instantaneous phase inductance, flux linkage, coenergy and electromagnetic torque as a function of rotor position and winding currents are derived. And it is compared with the results of the finite element analysis.

• Journal of Power Electronics
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• v.9 no.1
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• pp.68-73
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• 2009

Automotive inverters may require current sensors for motor torque control, especially, in applications of hybrid electric vehicles or fuel cell vehicles. In this paper, to achieve a compact, integrated and low cost current sensor, a hall current sensor without magnetic core is introduced for integrating an automotive inverter. The compactness of the current sensor is possible by using integrated magnetic concentrators based on the Hall effect. Magnetic fields caused by three-phase currents are analyzed and a magnetic shield design is proposed for decoupling the cross-coupled field. It offers galvanic isolation, wide bandwidth (>100kHz), and accuracy(< 1%). Using 2D FEM analysis, its performance is demonstrated with design parameters at a U-shaped magnetic shield. The proposed coreless current sensor is tested with rated current to validate the linearity and accuracy.

• Analytical Science and Technology
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• v.17 no.6
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• pp.527-531
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• 2004

Treatment with aqueous sodium hydroxide solution plays an important role to impart certain desirable properties - feel and luster on the surface of polyester fiber. In this process alkali wastewater contains disodium terephthalate, ethylene glycol (EG) and residual sodium hydroxide. In this paper we report a new method containing the pretreatments of derivatization with benzoyl chloride and solvent extraction using pentane. The calibration curve of EG determined by GC/MS-SIM shows a good linearity in the range of 0.1 to $25{\mu}g/mL$ having the standard deviation of ${\leq}8.7%$. The recovery and the detection limit of this method are 91.9-93.7% and $0.05{\mu}g/mL$ respectively.

• Magazine of the Korean Society of Agricultural Engineers
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• v.36 no.3
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• pp.144-154
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• 1994

An efficient tidal model, TIDE which is an iterative type, nonlinear finite element model has developed for the analysis of the tidal movement in the coastal area which is characterized by irregular boundaries and bottom topography. Traditional time domain finite element models have been in difficulties with requirement for high eddy viscosity coefficients and small time steps to insure numerical instability. These problems are overcome by operating in the frequency domain with an elaborate grid system by combining the triangular and quadrilateral shape grids. Furthermore, in order to handle non-linearity which will be more significant in the shallow region, an iterative scheme with least square error minimization algorithm has been implemented in the model. The results of TIDE model are agreed with the analytical solutions in a rectangular channel under the condition of tidal waves entering the channel closed at one end.

• Natural Product Sciences
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• v.22 no.1
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• pp.1-12
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• 2016

Compositional differences in flavonoids are varied in the big family of Compositae. By summarizing our previous analytical studies and other scientific evidences, new strategy will be possible to further analyze flavonoids and utilize them for human health. The HPLC analytical method has been established in terms of linearity, sensitivity, accuracy, and precision. Herbs of the family of Compositae have considerable amounts of peroxynitrite ($ONOO^-$)-scavenging effects and their phenolic substances. These effects may contribute to the prevention of disease associated with excess production of $ONOO^-$, depending on the high content of flavonoid substances.

• Korean Journal of Remote Sensing
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• v.16 no.2
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• pp.135-143
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• 2000

Ocean Scanning Multispectral Imager (OSMI) is a payload on the Korean Multi-Purpose SATellite (KOMPSAT) to perform global ocean color monitoring for the study of biological oceanography. HOMPSAT was launched 21 December 1999. The radiometric performance of OSMI is analyzed for various gain settings in the viewpoint of the instrument developer for OSMI calibration and application based on its ground performance data measured before launch. The radiometric response linearity and dynamic range are analyzed and the dynamic range is compared with the nominal input radiance for the ocean and the land. The noise equivalent radiance (NER) corresponding to the instrument radiometric noise is compared with the radiometric resolution of signal digitization (1-count equivalent radiance). The best gain setting of OSMI for ocean monitoring is recommended. This analysis is considered to be useful for the OSMI mission and operation planning, the OSMI image data calibration, and users' understanding about OSMI image quality.

• Structural Engineering and Mechanics
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• v.22 no.1
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• pp.107-130
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• 2006

The paper deals with the numerical solution of the dynamic problem of masonry structures. Masonry is modelled as a non-linear elastic material with zero tensile strength and infinite compressive strength. Due to the non-linearity of the adopted constitutive equation, the equations of the motion must be integrated directly. In particular, we apply the Newmark or the Hilber-Hughes-Taylor methods implemented in code NOSA to perform the time integration of the system of ordinary differential equations obtained from discretising the structure into finite elements. Moreover, with the aim of evaluating the effectiveness of these two methods, some dynamic problems, whose explicit solutions are known, have been solved numerically. Comparisons between the exact solutions and the corresponding approximate solutions obtained via the Newmark and Hilber-Hughes-Taylor methods show that in the cases under consideration both numerical methods yield satisfactory results.