• Journal of the Korean Regional Science Association
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• v.13 no.2
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• pp.45-54
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• 1997

A regional economy is characterized as a spatial economy. However the literature shows that it has been treated as a point economy since space is little recognized in regional modeling due to mathematical complication. This leads to the fact that regional model does not sufficiently represent regional characteristic. This paper attempts to construct a regional growth model in a partial equilibrium framework specifically taking into consideration land as a primary factor. The model is formulated largely neoclassical. Labor is assumed to move in response to differences in the wage rate, while capital is perfectly mobile across regions. The paper shows that two growth equilibrium points exist, one stable equilibrium point and the other unstable equilibrium point. The unstable growth equilibrium indicates the existence of minimum threshold that a region must overcome the minimum threshold to grow constantly. Consequently, directions of regional growth are characterized by two growth paths depending on the initial condition of a region. That is to say, a region below the minimum threshold is converging toward the lower stable equilibrium point over time. When a regional economy initially lies above the minimum threshold, it will grow forever. A regional economy is not thus necessarily converging a stationary is not thus necessarily converging a stationary equilibrium point through factor movement. Finally, the impacts of the presence of agglomeration economies and diseconomies are analyzed through the phase diagram. The paper also shows that agglomeration economies result in lowering the minimum threshold and in escalating the level of stable equilibrium However, when agglomeration diseconomies prevail, the results are opposite, i.e., rising the minimum threshold of growth and lowering the growth level of stable equilibrium.

• Journal of Korea Water Resources Association
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• v.46 no.5
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• pp.491-504
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• 2013

In this study, wave breakings over a shelf region are investigated under irregular wave conditions through laboratory experiments in a wave flume. Numerical simulations based on the Boussinesq-type equations are also conducted. The characteristics of breaking waves such as significant wave height, crest and trough heights, the mean water level and the stable wave height are obtained by analyzing laboratory measurements in detail. Obtained results are compared with those of the Boussinesq-type equations model. A very reasonable agreements is observed. The broken waves over a horizontal bottom asymptotically approach a stable wave height($H_{stable}$). In this study, the relative stable wave height is found as $H_{stable}/h{\fallingdotseq}0.56$ for irregular wave.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.29B no.1
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• pp.67-75
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• 1992

A new method of driving the PDP(Plasma Display Panel) was proposed and its characteristics were investigated. Applying high frequency non-discharge pulses to an auxiliary anode resulted an increased region of stable operation, decreased delay time and increased light intensity. It is suggested that PDP with DPM (Double Pulse Memory) drive technique improves the delay time, luminance, region of stable operation and luminous efficacy compared to PDP with PPM(Planar Pulse Memory) drive technique developed by NHK Lab. in Japan.

• ETRI Journal
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• v.26 no.4
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• pp.332-343
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• 2004

One of the recent and most significant technical properties can be expressed as "digital convergence," which is helping lead the technical paradigm into a ubiquitous environment. As an initial trial of realizing a ubiquitous environment, the convergence between broadcasting and telecommunication fields is now on the way, where it is required to develop a scalable video coding scheme for one-source and multi-use media. Traditional scalable video coding schemes have, however, limitations for higher stable picture quality especially on the region of interest. Therefore, this paper introduces an adaptive scanning method especially designed for a higher regional-stable picture quality under a ubiquitous video coding environment, which can improve the subjective quality of the decoded video by most-preferentially encoding, transmitting, and decoding the top-priority image information of the region of interest. Thus, the video can be more clearly visible to users. From various simulation results, the proposed scanning method in this paper can achieve an improved subjective picture quality far better than the widely used raster scan order in conventional video coding schemes, especially on the region of interest, and without a significant loss of quality in the left-over region.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.3 no.3
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• pp.597-605
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• 1999

In this paper, we propose a cardioangiography sequence image coding scheme which use a subtraction between initial image and current frame inserted contrast dye. Stable regions are obtained by the multithreshold and meaningful region is extracted by the images with stable region. The image with meaningful region is classified into contour and texture information. Contour information is coded by contour coding. And texture information is approximated by two-dimensional polynomial function and each coefficients is coded. Experimental results confirm that the sequence of cardioangiography are well reconstructed at the low bit rate (0.02∼0.04 bpp) and high compression ratio.

• 한국연소학회:학술대회논문집
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• 2007.05a
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• pp.69-75
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• 2007

In this study, the difference of flame stability zone for natural gases from producing districts was studied experimentally using a new type of flame stability diagram. The similarity of stable flame zone between a domestic appliance and an interchangeability test(IT) burner is also examined. As a result, the stable flame zones expressed by limits curves of flame lifting and yellow tipping show the similar results in a domestic gas range and IT burner. Furthermore, IT burner can reproduce the flash back phenomena and show the distinct difference of fuel type as the burner diameter is increased. To suggest the new type of flame stability diagram in the respect of fuel interchangeability, the air flowrate and Wobbe fuel flowrate were adopted as axis coordinates. It can be identified that the new diagram can provide the useful information on the difference of flame stability zone, heat input rate and air-fuel ratio when a fuel is altered to other fuels under the identical operating conditions. Finally, the stable flame zones for natural gas of 6 type are compared, and the detailed information to use as the interchangeability fuels of standard natural gas is provided using the new type of flame stability diagram.

• Korean Journal of Optics and Photonics
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• v.17 no.5
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• pp.447-454
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• 2006

We obtained analytic solutions of boundary conditions to the stable region of Z-fold $Cr^{4+}$ : YAG laser cavity when the conditions are with and without thermal tensing effect. Also we investigated the influence of the thermal tensing effect on the stability of cavity, beam waist, and astigmatic compensation using aberration transformation matrices. The thermal tensing effect almost has no influence on the stable region of the cavity when the crystal is located in the middle of two concave mirrors and when the distances from the concave mirror to the reflecting mirror and the output coupler are the same. The beam waist, however, is affected more in a tangential plane than in a sagittal plane, and so it is difficult to have astigmatic compensation when the thermal tensing effect exists. This result means that the thermal tensing effect should be considered even for the Kerr-lens mode-locking.

• Korean Journal of Computational Design and Engineering
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• v.8 no.1
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• pp.41-47
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• 2003

In this paper, a tetrahedral mesh generation algorithm which uses a grid based method for interior region and an advancing front method for outer surface region is proposed. In order to apply an advancing front method for outer region of an object, a new operator so called a hole operator has been developed to handle multiple shells. With this grid based approach in the interior region, more stable and uniform meshes can be constructed especially in the interior region.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.21 no.6
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• pp.822-829
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• 1997

A catalytic burner was studied which can be used as a heater operated in medium temperature. Noble metal catalysts (Pd/NiO) were used, which were supported on alumina wash coated honeycomb. The maximum heat-resisting temperature of the catalyst is about 900.deg. C. Combustion efficiency of the catalytic burner reached more than 99.5 % at the excess air ratio above 1.25.NOx emissions were lower than 1.0 ppm at all operation conditions. The operation condition for a stable catalytic combustion was obtained. It was dependent on the catalyst thickness. The 30 mm thick catalyst showed the widest stable catalytic combustion region. Stable catalytic combustion region of 30 mm thick catalyst was the operation condition of excess air ratio 1.25 - 1.75 and heat flux 7 - 14 kcal/h center dot cm$^{2}$.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.849-850
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• 2006

This thesis presents a new analysis method of Vegas network model in single link single source and a new version of Vegas for expanding asymptotically stable region. Actually since original Vegas model is difficult to analysis, we use a modified Vegas network model. Since there is a few tools to analyze nonlinear system with delay, developing other methods is very important and useful. We used state space model in discrete time. Using by Jury's criterion, we could find asymptotically stable region of Vegas network model. And it was a if and only if condition. Moreover, we proposed a new version of Vegas algorithm. To expand asymptotically stable region we modified the original Vegas model. The new analysis method and new Vegas algorithm were justified by ns-2 simulation. And as compare with other result, we could know our method has many advantages.