• Transactions of the Korean Society of Mechanical Engineers A
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• v.22 no.4
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• pp.924-938
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• 1998

Densification behavior of ceramic powder under cold compaction was investigated. Experimental data were obtained for zirconia powder and alumina powder under triaxial compression with various loading conditions. A special form of the Cap model was proposed from experimental data under triaxial compression for a yield function of ceramic powder. The proposed yield function was inplemented into a finite element program (ABAQUS) to study densification behaviors of zirconia and alumina powders under die compaction. The effect of friction between the powder and die wall was also investigated. Density distributions of powder compacts were measured and compared with finite element results.

• Journal of electromagnetic engineering and science
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• v.7 no.1
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• pp.7-11
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• 2007

PCB Power-Bus (comprising power/ground planes) impedance and fields are evaluated by an efficient series expansion method that is suggested in this paper. It is used to investigate the structure's radiated emission(RE) levels and find acceptable ways of loading the power/ground planes such as decoupling capcitor(DeCap)s, balanced feeding and slits, in order to reduce the interferences. Also, the calculations and measurements of a proposed geometry are verified by vector fitting as a analysis model to check the behavior of the slit.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.2 no.4
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• pp.473-484
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• 1998

The current interconnection charge regimes is based in fully distributed costing method. Basically this method doesn't give the incument carrier the incentive to promote efficient business operations. In this paper, 1 suggest the adoption of price cap regulation to interconnection charge as incentive schemes and review important considerations in its applications. Additionally I suggest the basic structure of the network costing model for applications of incremental costing method.

• Computers and Concrete
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• v.6 no.5
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• pp.377-390
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• 2009

In this paper an improved one-dimensional frame element for modelling of reinforced concrete beams and columns subjected to impact is presented. The model is developed in the framework of a flexibility fibre element formulation that ignores the shear effect at material level. However, a simple shear cap is introduced at section level to take account of possible shear failure. The effect of strain rate at the fibre level is taken into account by using the dynamic increase factor (DIF) concept for steel and concrete. The capability of the formulation for estimating the element response history is demonstrated by some numerical examples and it is shown that the developed 1D element has the potential to be used for dynamic analysis of large framed structures subjected to impact of air blast and rigid objects.

• Journal of electromagnetic engineering and science
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• v.7 no.4
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• pp.175-182
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• 2007

In this paper, a study on the reflector type frequency doubler, to suppress the undesired harmonics, is presented. A 12 to 24 GHz reflective frequency doubler is simulated and experimented. Design procedure of the frequency doubler with reflector is provided and the frequency doubler with good spectral purity is fabricated successfully. It has harmonic suppression of the $40{\sim}50\;dBc$ in the $1^{st}$ harmonic and the $50{\sim}60\;dB$ in the $3^{rd}$ harmonic with no additional filter. And, it has conversion gain with the input power of 0 dBm over bandwidth of 500 MHz. A NEC's ne71300(N) GaAs FET is used and the nonlinear model(EEFET3) using IC-CAP program is extracted for harmonic load pull simulation. Good agreement between simulated and measured results has been achieved.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.11
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• pp.84-93
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• 2009

In this paper, we propose to study the possibility of using a photovoltaic system combined with a high speed micro-turbine. This hybrid system can work as stand-alone system or grid connected system as it will be a part of a micro-grid. Initially, we propose Matlab/Simulink dynamic models of photovoltaic, micro turbine systems and supercapacitor. Then, we carry out a simulation comparison of the two systems, this is, with supercapacitor and without supercapacitor bank. We show that supercapacitor bank as short-term storage device was necessary to reduce the fast fluctuation of power in the case of sensitive loads. It is verified the simulation results of Matlab/Simulink based hybrid power system represent the effectiveness of the suggested hybrid power system.

• 한국신재생에너지학회:학술대회논문집
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• 2008.10a
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• pp.295-298
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• 2008

The major function of the nacelle cover is protecting the inside equipments. Therefore, it is required not only sufficient strength and stability but also light weight. In this paper, design loads are calculated according to the GL Wind guideline Ed. 2003. To ensure the structural safety, a composite structure is selected. The structural design is processed by two steps which are preliminary design and detail design. In the preliminary design step, a structural analysis is performed with initial thickness, 5mm. As reviewing above analysis results, weak regions of the nacelle cover reinforced using the spar cap structure which is same as the blade structure. In the analysis model, the support structure is connected with the nacelle cover and analyzed its structural safety at the same time.

• Journal of the Korean Institute of Navigation
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• v.18 no.2
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• pp.69-81
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• 1994

Studies on the ship's automatic navigation & berthing control have been continued by way of solving the ship's mathematical model, but the results of such studies have not reached to our satisfactory level due to its non-linear characteristics at low speed. In this paper, the authors propose a new berthing control system which can evaluate as closely as cap-tain's decision-making by using the FNN(Fuzzy Neural Network) controller which can simulate captain's knowledge. This berthing controller consists of the navigation subsystem FNN controller and the berthing subsystem FNN controller. The learning data are drawn from Ship Handling Simulator (NavSim NMS-90 MK Ⅲ) and represent the ship motion characteristics internally. According to learning procedure, both FNN controllers can tune membership functions and identify fuzzy control rules automatically. The verified results show the FNN controllers effective to incorporate captain's knowledge and experience of berthing.

• Proceedings of the KIEE Conference
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• 2003.07a
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• pp.615-617
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• 2003

In electricity market with a imperfect competition, participants make plans of biddings and transaction strategies to maximize their own profits. The market price and the quantity are determined by bidding systems and market demands. Practically the characteristics of power demand have rather two forms; elastic region and inelastic region, than constant slope elasticity. Furthermore the price cap in the market can be modelled as a region of perfect elasticity in the demand function. This paper analyses supplier's bidding strategies which are reflected the characteristics of practical demand. Equilibrium strategies are solved by using the Bertrand model and payoff matrices.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.12
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• pp.2194-2198
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• 2008

In this paper, the construction of secondary reaction plate is analyzed by 3-D Finite Element Method(3-D FEM) to consider the influence of its variation on the transverse edge effect of LIM. The effective 3-D analysis model for considering the transverse edge effect caused by the finite widths of the primary and the secondary is proposed. The simple method measuring the transverse edge effect by using the patterns of currents induced in the secondary reaction plate is also proposed. With this effective analysis method, various models of secondary reaction plate with overhang and cap has been analyzed to consider the relationship between the construction of secondary reaction plate and the transverse edge effect of LIM.