• Journal of the Korean Operations Research and Management Science Society
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• v.34 no.1
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• pp.61-83
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• 2009

This study developed a variable demand traffic assignment model by stable dynamics. Stable dynamics, suggested by Nesterov and do Palma[19], is a new model which describes and provides a stable state of congestion in urban transportation networks. In comparison with the user equilibrium model, which is based on the arc travel time function in analyzing transportation networks, stable dynamics requires few parameters and is coincident with intuitions and observations on congestion. It is therefore expected to be a useful analysis tool for transportation planners. In this study, we generalize the stable dynamics into the model with variable demands. We suggest a three stage optimization model. In the first stage, we introduce critical travel times and dummy links and determine variable demands and link flows by applying an optimization problem to an extended network with the dummy links. Then we determine link travel times and path flows in the following stages. We present a numerical example of the application of the model to a given network.

• Journal of the Korean Operations Research and Management Science Society
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• v.32 no.3
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• pp.63-80
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• 2007

This study is a generalization of 'stable dynamics' recently suggested by Nesterov and de Palma[29]. Stable dynamics is a new model which describes and provides a stable state of congestion in urban transportation networks. In comparison with user equilibrium model that is common in analyzing transportation networks, stable dynamics requires few parameters and is coincident with intuitions and observations on the congestion. Therefore it is expected to be an useful analysis tool for transportation planners. An equilibrium in stable dynamics needs only maximum flow in each arc and Wardrop[33] Principle. In this study, we generalize the stable dynamics into the model with multiple traffic classes. We classify the traffic into the types of vehicle such as cars, buses and trucks. Driving behaviors classified by age, sex and income-level can also be classes. We develop an equilibrium with multiple traffic classes. We can find the equilibrium by solving the well-known network problem, multicommodity minimum cost network flow problem.

• The Journal of Korea Robotics Society
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• v.6 no.3
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• pp.230-236
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• 2011

In previous researches, the self-stability was studied for the spring-mass model and the two segment leg model. In these researches, it was presented that the spring-mass model has the self-stable region at relatively high speed running and the two segment leg model has the self-stable region at relatively low speed running. If the model was run in the self-stable region, the cost of transport is zero ideally. That is, actually, only the energy loss is needed to compensate for running. This means that the energy efficiency is high, running in the self-stable region. We want to have high energy efficiency at low and high speed running. So, in this paper, we propose the design direction of the three segment leg having the self-stable region at low and high speed running. And we prove the self-stable region of the three segment leg designed by the proposed design direction.

• Journal of the Korean Society of Safety
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• v.27 no.6
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• pp.54-58
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• 2012

This paper is purposed to analyze electric leakage component which can prevent electrical fires on breaker capacity expansion and power failure by operation of ELB(Earth leakage breaker) for stable sizes. In order to analysis for electric leakage component for stable sizes, this paper studied field state investigation which are at stable companies( 10 companies) in cheong-won location to deduce the problems of electric leakage component is analyzed. The field state experiment method is measured with electric leakage component which load part of ELB detected by electric loads(electrical fan, lighting, auto waterer, feeder and halogen lighting) and stable sizes. Results show that electric leakage component suggested in this paper are valuable and usable to electrical fire in leakage current based on environment factor, which will prevent severe damage to human beings and properties and reduce the electrical fires in stable.

• Journal of the Chungcheong Mathematical Society
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• v.16 no.1
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• pp.113-121
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• 2003

This paper is concerned with some properties of stable domains and limit functions. Using the relationship between cycles of periodic stable domains and orbits of critical points and using the Sullivan theorem [19], we prove that the value of a constant limit function in some stable domain for a rational function f of degree at least two lies in the closure of the set of critical orbits of f.

• Communications of the Korean Mathematical Society
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• v.32 no.2
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• pp.267-276
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• 2017

In this paper we introduce rings that satisfy regular 1-stable range. These rings are left-right symmetric and are generalizations of unit 1-stable range. We investigate characterizations of these kind of rings and show that these rings are closed under matrix rings and Morita Context rings.

• Journal of the Korea Convergence Society
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• v.5 no.4
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• pp.163-169
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• 2014

A stable neural network control scheme for unknown non-linear systems is developed in this paper. While the control variable is optimised to minimize the performance index, convergence of the index is guaranteed asymptotically stable by a Lyapnov control law. The optimization is achieved using a gradient descent searching algorithm and is consequently slow. A fast convergence algorithm using an adaptive learning rate is employed to speed up the convergence. Application of the stable control to a single input single output (SISO) non-linear system is simulated. The satisfactory control performance is obtained.

• Journal of the Korean Mathematical Society
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• v.48 no.2
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• pp.253-266
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• 2011

In this paper we give an upper bound of the first eigenvalue of the Laplace operator on a complete stable minimal hypersurface M in the hyperbolic space which has finite $L^2$-norm of the second fundamental form on M. We provide some sufficient conditions for minimal hypersurface of the hyperbolic space to be stable. We also describe stability of catenoids and helicoids in the hyperbolic space. In particular, it is shown that there exists a family of stable higher-dimensional catenoids in the hyperbolic space.

• Journal of the Korean Mathematical Society
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• v.38 no.1
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• pp.101-123
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• 2001

For a linear operator Q from R(sup)d into R(sup)d and 0$\alpha$ and parameter b on the other. characterization of strictly (Q,b)-semi-stable distributions among (Q,b)-semi-stable distributions is made. Existence of (Q,b)-semi-stable distributions which are not translation of strictly (Q,b)-semi-stable distribution is discussed.

• Journal of the Korean Mathematical Society
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• v.47 no.1
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• pp.1-15
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• 2010

We introduce, in this article, the quasi-stable exchange ideal for associative rings. If I is a quasi-stable exchange ideal of a ring R, then so is $M_n$(I) as an ideal of $M_n$(R). As an application, we prove that every square regular matrix over quasi-stable exchange ideal admits a diagonal reduction by quasi invertible matrices. Examples of such ideals are given as well.