• Proceedings of the Korean Society of Marine Engineers Conference
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• 2001.05a
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• pp.207-212
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• 2001

In this paper, a method to be able to decide the possible maximum gain of P, PI control for the retarded processes under stable condition is proposed. At first, adjustable parameter set causing stability limit are obtained based on the frequency domain condition which makes the roots of transfer function locate on the $j\omega$ axis. And the cut-in frequency $\omega{_p}$ to bring the parameter set to P control from PI control is derived by an equation with 2 parameters L and $T_m$ given, then $\omega{_p}$ is used to compute the maximum gain with stable condition. For the calculation, the controlled process of first order system with time delay element is introduced and all parameters are presumed to be time invariant.

• Journal of the Korean Institute of Telematics and Electronics
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• v.13 no.6
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• pp.7-11
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• 1976

A voltage-stable negative resistance circuit with operational amplifier is proposed, and circuit analysis is given all the input voltage range. The behavior of the v-i characteristics in the nogative resistance region is devided into two causes, and top points in the input v-i characteristics of the circuit is analyzed with them. Experimental results of the v-i characteristics of the proposed circuit has a good linearity in the negative region with negative resistance, -86$\Omega$~-833$\Omega$ for the input voltage, $\pm$ 1~$\pm$ 5 colts. The v-i characteristics of the circuit in all the input voltage range is discussed.

• Journal of Korea Multimedia Society
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• v.13 no.1
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• pp.38-46
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• 2010

A stable game managing system is absolutely needed to accept simultaneous interlacing of many users for on- line game system. The proposed P2P on-line game system in this paper is able to get stable and real-time game managing within limited time stamp utilizing through reorganizing peers according to synchronous time which can be avoid congestion on one region, it is possible to synchronize for game nodes within limited time stamp utilizing. Reorganizing M-tree which leads 10 distribute loads. The system manages each region unit, and it is execute no matter how big game sizes are. Thus to ensure such as the problems of expand server and stabilization or message transmission. Also, prove efficiency of the suggested system through the simulation.

• Journal of Korea Multimedia Society
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• v.12 no.3
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• pp.345-353
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• 2009

It is for sure that a stable game managing system is absolutely needed to accept simultaneous interfacing of many users for P2P on-line game system. The proposed P2P on-line game system in this paper is able to get smart and stable game managing taking care of extensive players through reorganizing numerous RS(Region Server) and mutual communications among RS's which can be avoid congestion on one region. Moreover, it is possible to synchronize for game nodes in time stamp utilizing Global Zone Buffer of Monitoring Server which leads to breakup loads. The system manages middleware layers in the so-called sub area, and it is able to execute no matter how big the game sizes are. That means, in some ways, we got everything we try to ensure such as the problems of high cost server and stabilization of message transmission. This paper welcomes to prove efficiency of the suggested system through the simulation.

• Journal of the Korean Regional Science Association
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• v.15 no.1
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• pp.63-73
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• 1999

It is generally believed that there is a trade-off between economic growth and environmental quality since pollutants are generated in the process of production and consumption of commodities. Several researchers have shown this prevailing belief using the short-term input-output models. The literature, however, shows that there have been few attempts to investigate the relationship using long-term forecasting models. This motivates the current paper. This paper attempts to build a reginal growth model in a partial equilibrium framework taking into consideration the requirements of capital invested for pollutant abatement. Model is largely neoclassical. Labor is assumed to move a region with high utility specified in regional per capita average was income and pollution level while capital is partially mobile to a region with high returns. The regional growth is explored in a phase diagram. The paper shows that there are two stable growth equilibria which a region can converge over time and that the equilibria are distinguished by the initial threshold capital stock that a region holds. If the initial capital stock of a region is over(under) than the threshold size, the region converges to the higher (lower) growth equilibrium over time. Moreover, based on this result an environmental quality enhancing policy is analyzed in the phase diagram. It has revealed that the policy calls for the relocation of growth equilibrium points, specifically speaking, it stimulates an increase in labor stock and a decrease in capital stock. Hence the paper has suggested that the prevailing belief which the environmental policy negatively impacts on a regional economic growth is not always true.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.11a
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• pp.1001-1002
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• 2010

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.11a
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• pp.203-204
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• 2010

• Proceedings of the Zoological Society Korea Conference
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• 1999.10b
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• pp.290.2-290
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• 1999

No Abstract, See Full Text

• The Journal of Korea Robotics Society
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• v.6 no.4
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• pp.301-307
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• 2011

Based on the stability criteria of ZMP (Zero Moment Point), this paper proposes an adjusting algorithm that modifies walking trajectory of a bipedal robot for stable walking by analyzing ZMP trajectory of it. In order to maintain walking balance of the bipedal robot, ZMP should be located within a supporting polygon that is determined by the foot supporting area with stability margin. Initially tilting imposed to the trajectory of the upper body is proposed to transfer ZMP of the given walking trajectory into the stable region for the minimum stability. A neural network method is also proposed for the stable walking trajectory of the biped robot. It uses backpropagation learning with angles and angular velocities of all joints with tilting to get the improved walking trajectory. By applying the optimized walking trajectory that is obtained with the neural network model, the ZMP trajectory of the bipedal robot is certainly located within a stable area of the supporting polygon. Experimental results show that the optimally learned trajectory with neural network gives more stability even though the tilting of the pelvic joint has a great role for walking stability.

• Journal of Environmental Science International
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• v.10 no.5
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• pp.329-336
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• 2001

Characgcteristics of nocturnal boundary layer(NBL) were analyzed by the upper-air observations data using with the airsonde and pilot balloons from 1994 to 1999 in Kyungpook province. The automate weather boundary layer can become stably stratified when the surface is cooler than the air. Stable nocturnal boundary layer height were estimated from the top of surface stable layer where the vertical gradient of temperature and mixing ratio tend to zero or negative. The depth of the stable nocturnal boundary layer depended largely on the thermal effect rather than the wind effect at nighttime. The NBL was more developed on the land than on the coastal region. The stability index (bulk Richardson number) showed that the NBL was stable when the wind was weak and the vertical gradient of the temperature was strong. The heat budget in the NBL was studied by considering the effect of the radiative and the cooled by both the longwave radiative flux and the divergence of the heat flux, while NBL under the cloudy sky the longwave radiative flux played a role of the warming. It was noted that the heat was not conserved in both cases. To complete the heat budget in the NBL the warming/cooling by advection and subsidence must be considered.