• Journal of applied mathematics & informatics
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• v.32 no.1_2
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• pp.211-225
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• 2014

A new class of smoothing functions is introduced in this paper, which includes some important smoothing complementarity functions as its special cases. Based on this new smoothing function, we proposed a smoothing Newton method. Our algorithm needs only to solve one linear system of equations. Without requiring the nonemptyness and boundedness of the solution set, the proposed algorithm is proved to be globally convergent. Numerical results indicate that the smoothing Newton method based on the new proposed class of smoothing functions with ${\theta}{\in}(0,1)$ seems to have better numerical performance than those based on some other important smoothing functions, which also demonstrate that our algorithm is promising.

• Journal of the Korean Magnetics Society
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• v.11 no.2
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• pp.78-83
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• 2001

The thermal characteristics of TMR devices by using Fast Linear Annealing method has been studied. A computer program that employs the finite differential method has been developed to simulate the temperature distribution of a diameter of 4" silicon wafer, which is subjected to radiation heat from the halogen lamp. We adopted the temperature of 350$\^{C}$, which is the highest temperature usually used in annealing for magnetic thin films. We changed moving velocity of the lamp from 0.05 mm/sec to 1 mm/sec. The moving velocity of halogen lamp has less effect on the local peak temperature of the sample only about 40$\^{C}$. Therefore, we may be able to anneal TMR devices in such short time of 1 minute and 40 seconds per one wafer, using the Fast Linear Annealing method.

• Structural Engineering and Mechanics
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• v.25 no.1
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• pp.53-73
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• 2007

In this study, an effective load increment method for multi modal adaptive non-linear static (pushover) analysis (NSA) for building type structures is presented. In the method, lumped plastisicity approach is adopted and geometrical non-linearties (second-order effects) are included. Non-linear yield conditions of column elements and geometrical non-linearity effects between successive plastic sections are linearized. Thus, load increment needed for formation of plastic sections can be determined directly (without applying iteration or step-by-step techniques) by using linearized yield conditions. After formation of each plastic section, the higher mode effects are considered by utilizing the essentials of traditional response spectrum analysis at linearized regions between plastic sections. Changing dynamic properties due to plastification in the system are used on the calculation of modal lateral loads. Thus, the effects of stiffness changes and local mechanism at the system on lateral load distribution are included. By using the proposed method, solution can be obtained effectively for multi-mode whereby the properties change due to plastifications in the system. In the study, a new procedure for determination of modal lateral loads is also proposed. In order to evaluate the proposed method, a 20 story RC frame building is analyzed and compared with Non-linear Dynamic Analysis (NDA) results and FEMA 356 Non-linear Static Analysis (NSA) procedures using fixed loads distributions (first mode, SRSS and uniform distribution) in terms of different parameters. Second-order effects on response quantities and periods are also investigated. When the NDA results are taken as reference, it is seen that proposed method yield generally better results than all FEMA 356 procedures for all investigated response quantities.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.3C
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• pp.234-240
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• 2002

A power amplifier with AlGaAs/InGaAs/GaAs HBT's has been developed for customer premise equipments of the quasi millimeter-wave frequency-band broadband wireless local loop(BWLL) system. Parameters of the linear and nonlinear equivalent circuits for a common base HBT have been extracted by a fitting method. The amplifier has been designed through the linear and nonlinear circuit simulations and fabricated on a ceramic substrate for a hybrid IC. The amplifier has produced a 25.5-dBm output power with 35% power-added efficiency(PAE) at 24.4 GHz and achieved a 7.5-dB linear power gain at 24.8 GHz. In 24.25 ∼24.75 GHz band, the amplifier has exhibited a saturated output over larger than 22 dBm and PAE higher than 25%.

• Korea Trade Review
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• v.46 no.2
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• pp.213-228
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• 2021

In recent year, US government requires local investment ,unlike in the past, when import restrictions and tariff were imposed. In this situation, many companies are considering new investment in the US and entering the local market. However, research on the optimal investment plan along with the case analysis on trade regulation is extremely limited and more research needs to be conducted. Accordingly, this study aims to suggest the implications and countermeasure of the SCM and logistical perspective by studying the optimal measures for the new investment of each company due to trade regulation. As a research method, the gravity location model, Mixed Integer Linear Programming Model were used to select the optimal automobile manufacturing factory considering each state's population. This study will be implication of SCM and logistics perspective not only for companies considering new investment in the US but also for the government to conduct trade negotiations. In the future, it is expected that the US trade pressure will increase and affect Korea in many ways. Therefore, in order to cope with such difficult situation in a timely manner, continuous research considering various possibilities is needed in the future.

• The Pure and Applied Mathematics
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• v.16 no.4
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• pp.427-441
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• 2009

The method of Lattice Dynamical System is used to establish a global model on an infinite chain of many local markets interacting each other through a diffusion of prices between them. This global model extends the Walrasian evolutionary cobweb model in an independent single local market to the global market evolution. We assume that each local market has linear decreasing demands and quadratic supplies with naive predictors, and investigate the stationary behaviors of global price dynamics and show that their dynamics are conjugate to those of $H{\acute{e}}non$ maps and hence can exhibit complicated behaviors such as period-doubling bifurcations, chaos, and homoclic orbits etc.

• International journal of steel structures
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• v.18 no.5
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• pp.1761-1771
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• 2018

In this paper, a hysteretic model of rectangular hollow section (RHS) columns that includes the deteriorating range caused by local buckling is proposed. The proposed model consists of the skeleton curve, the Bauschinger part that appears before reaching the maximum strength, the strength increasing part of the deteriorating range, and the unloading part. Of these, the skeleton curve, including the deterioration range caused by local buckling, which is considered to be equivalent to the load-deformation relationship under monotonic loading, is obtained through an analytical method. Bi-linear hysteretic models based on experimental results are applied to the Bauschinger part and the strength increasing part. The elastic stiffness is applied to the unloading part. The proposed model is verified by comparing with experimental results of RHS columns under monotonic and cyclic loading.

• Journal of the Korean Mathematical Society
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• v.52 no.3
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• pp.469-487
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• 2015

We consider a model of HIV infection with various compartments, including target cells, infected cells, viral loads and immune effector cells, to describe HIV type 1 infection. We show that the proposed model has one uninfected steady state and several infected steady states and investigate their local stability by using a Jacobian matrix method. We obtain equations for adjoint variables and characterize an optimal control by applying Pontryagin's Maximum Principle in a linear control problem. In addition, we apply techniques and ideas from linear optimal control theory in conjunction with a direct search approach to derive on-off HIV therapy strategies. The results of numerical simulations indicate that hybrid on-off therapy protocols can move the model system to a "healthy" steady state in which the immune response is dominant in controlling HIV after the discontinuation of the therapy.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.717-718
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• 2008

Fisher Linear Discriminant(FLD) is a sample and intuitive linear feature extraction method in pattern recognition. But in some special cases, such as un-separable case, one class data dispersed into several clustering case, FLD doesn't work well. In this paper, a new discriminant named K-means Fisher Linear Discriminant, which combines FLD with K-means clustering is proposed. It could deal with this case efficiently, not only possess FLD's global-view merit, but also K-means' local-view property. Finally, the simulation results also demonstrate its advantage against K-means and FLD individually.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.1409-1415
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• 2010

A linear induction motor have advantages for reducing mechanical frictions and noises because it has thrust force by induced torque instead of friction force between rail and wheels. An it has additional advantage for reducing volume of bogie frame for light rail transit. The small volume causes the cost of construction down. Recently, researches of linear induction motor for thrust force of the light rail transit have been actively studied. For the rail transit, vehicle is running as follow accelerating and constant speed, finally decelerating speed passing local stops between stations. The light rail transit have only these three patterns of operating. Thus, design of that has different design specifications from others. In this paper, the linear induction motor for the light rail transit was designed considering the goal speed, accelerating time, and accelerating distance for approaching the goal speed. The designed motor was proved that it could meet the requirement of accelerating performance by2-dimensional finite element method and mechanical dynamics equation.