• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1468-1471
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• 2005

This Paper is to find out a solution for the full-coverage algorithm requiring the real-time processing such as mobile home service robots and vacuum cleaner robots. Previous methods are used by adopting based grid approach method. They used lots of sensors, a high speed CPU, expensive ranger sensors and huge memory. Besides, most full-coverage algorithms should have a map before obstacle avoidance. However, if a robot able to recognize the tangent vector of obstacles, it is able to bring the same result with less sensors and simplified hardware. Therefore, this study suggests a topological based approach and a local obstacle voidance method using a few of PSD sensors and ultra sonic sensors. The simulation results are presented to prove its applicability.

• Journal of Korea Multimedia Society
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• v.10 no.12
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• pp.1645-1654
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• 2007

In this paper, we study the problem of load balancing routing in clustered-based wireless mesh network in order to enhance the overall network throughput. We first address the problems of cluster allocation in wireless mesh network to achieve load-balancing state. Due to the complexity of the problem, we proposed a simplified algorithm using gradient load-balancing model. This method searches for a localized optimal solution of cluster allocation instead of solving the optimal solution for overall network. To support for load-balancing algorithm and reduce complexity of topology control, we also introduce limited broadcasting between two clusters. This mechanism maintain shortest path between two nodes in adjacent clusters while minimizing the topology broadcasting complexity. The simulation experiments demonstrate that our proposed model achieve performance improvement in terms of network throughput in comparison with other clustering methods.

• Journal of Korea Multimedia Society
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• v.14 no.12
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• pp.1559-1571
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• 2011

In wireless ad hoc networks, nodes communicate with each other using multihop routed transmission in which hop-by-hop cooperative diversity can be effectively employed. This paper proposes (i) two cooperation models for per-link cooperation (PLC) and per-node cooperation (PNC) for exploiting cooperative diversity in wireless ad hoc networks and (ii) a cooperative routing algorithm for the above models in which best relays are selected for cooperative transmission. First, two cooperation models for PLC and PNC are introduced and represented as an edge-weighted graph with effective link quality. Then, the proposed models are transformed into a simplified graph and a cooperative routing algorithm with O(n2) time is developed, where n is the number of nodes in the network. The effectiveness of the algorithm is confirmed for the two cooperation models using simulation.

• 제어로봇시스템학회:학술대회논문집
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• 1991.10a
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• pp.419-424
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• 1991

In this paper, a fuel minimizing closed loop explicit inertial guidance algorithm for the orbit injection of a rocket is developed. In this formulation, the fuel burning rate and magnitude of thrust are assumed constant, and the motion of a rocket is assumed to be subject to the average inverse-square gravity, but with negligible atmospheric effects. The optimum thrust angle for obtaining the given velocity vector in the shortest time with minimizing fuel consumption is first determined, and then the additive thrust angle for targeting the final position vectors is determined by using Pontryagin's Maximum Principle. To establish the real time processing, many algorithms of the onboard guidance software are simplified. Simulations for the explicit guidance algorithm, for the 2nd-stage flight of the N-1 rocket, are carried out. The results show that the guidance algorithm works well in the presence of the maximum .+-.10 % initial velocity and altitude error. The effects of the guidance cycle time is also examined.

• 제어로봇시스템학회:학술대회논문집
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• 1992.10b
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• pp.545-549
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• 1992

In general, recognition of Hand written characters requires to apply an algorithm which takes into consideration of the individual differences. Considering the differences, the authors propose a new method for recognizing Hand written Hangul by parallel procedure analyzing both the segments and the structure of the character. In the previous recognition method proposed by the authors two severe restrictions were placed. The element representing consonant/O/ was closed, and the character elements were separated each other. In order to remove these two restrictions, the authors propose an improved algorithm. It is shown that Hangul in its simplified form is well recognized by using this improved algorithm.

• Proceedings of the KIPE Conference
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• 2003.07b
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• pp.785-788
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• 2003

In this paper , the simple MPPT(Maximum Power Point Tracking) control algorithm is proposed for the grid-connected photovoltaic power system. This method uses the difference in the slope of the solar array voltage range below the MPP and above the MPP. This simple the algorithm enables the hardware implementation achieved by only analog devices. The proposed MPPT algorithm is verified by the hardware experiment using 500[W] solar away simulator, simplified inverter model hardware set, and rectified grid-line.

• Proceedings of the KIEE Conference
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• 2002.11c
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• pp.83-86
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• 2002

This paper presents an implementation of Pill controller for DC-DC converter using the microcontroller. The features of the microcontroller such as the on chip ADC and Pulse width Modulator (PWM) eliminate the external components needed to perform these functions. The duty rate cycle for the DC-DC converter can be updated every time when the (ADC) conversation and the calculation time are finished. The stable response can be obtained for any kind of DC-DC converters. The SMPS controller looks at the converter output, compares the output to a set point, performs a control algorithm (Pill algorithm) and finally applies the algorithm output to the PWM. PWM output is then used to drive the DC-DC converter. Figure (1) shows a simplified block diagram of a complete DC-DC converter system.

• Journal of Korean Association for Spatial Structures
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• v.15 no.4
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• pp.81-89
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• 2015

Damped outrigger systems have been proposed as a novel energy dissipation system to protect tall buildings from severe earthquakes and strong wind loads. In this study, semi-active damping devices such as magnetorheological (MR) dampers instead of passive dampers are installed vertically between the outrigger and perimeter columns to achieve large and adaptable energy dissipation. Control performance of semi-active outrigger damper system mainly depends on the control algorithm. Fuzzy logic control algorithm was used to generate command voltage sent to MR damper. Genetic algorithm was used to optimize the fuzzy logic controller. An artificial earthquake load was generated for numerical simulation. A simplified numerical model of damped outrigger system was developed. Based on numerical analyses, it has been shown that the semi-active damped outrigger system can effectively reduce both displacement and acceleration responses of the tall building in comparison with a passive outrigger damper system.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.6
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• pp.97-106
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• 1998

In this Paper, a fuel minimizing closed loop explicit inertial guidance algorithm for orbit injection of a rocket is developed. In the formulation, the fuel burning rate and magnitude of thrust are assumed constant. The motion of rocket is assumed to be subject to the average inverse-square gravity, but negligible effects from atmosphere. The optimum thrust angle to obtain a given velocity vector in the shortest time with minimizing fuel consumption is first determined, and then the additive thrust angle for targeting the final position vector is determined by using Pontryagin's maximum principle. To establish real time processing, many algorithms of onboard guidance software are simplified. The explicit guidance algorithm is simulated on the 2nd-stage flight of the N-1 rocket developed in Japan. The results show that the explicit guidance algorithm works well in the presence of the maximum $\pm$10% initial velocity and altitude errors, and exhibits better performance than the open-loop program guidance. The effects of the guidance cycle time are also examined.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.8C
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• pp.751-755
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• 2003

This paper proposes the Μ-algorithm for overall efficiency rise with complexity decrease in magnetic recording channel PRML system. The if-algorithm is decoding method that omits some parts of state numbers. So it can decrease system's complexity that is increased according to channel density. This paper determines PRML channel model that shows good capacity for each channel density, and proposes the most suitable PRML system model with the relation of efficiency and complexity.