• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1846-1850
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• 2005

This paper presents a constrained-based routing (CBR) algorithm called, Dynamic Possible Path per Link (D-PPL) routing algorithm, for MultiProtocol Label Switching (MPLS) networks. In MPLS on-line routing, future traffics are unknown and network resource is limited. Therefore many routing algorithms such as Minimum Hop Algorithm (MHA), Widest Shortest Path (WSP), Dynamic Link Weight (DLW), Minimum Interference Routing Algorithm (MIRA), Profiled-Based Routing (PBR), Possible Path per Link (PPL) and Residual bandwidth integrated - Possible Path per Link (R-PPL) are proposed in order to improve network throughput and reduce rejection probability. MIRA is the first algorithm that introduces interference level avoidance between source-destination node pairs by integrating topology information or address of source-destination node pairs into the routing calculation. From its results, MIRA improves lower rejection probability performance. Nevertheless, MIRA suffer from its high routing complexity which could be considered as NP-Complete problem. In PBR, complexity of on-line routing is reduced comparing to those of MIRA, because link weights are off-line calculated by statistical profile of history traffics. However, because of dynamic of traffic nature, PBR maybe unsuitable for MPLS on-line routing. Also, both PPL and R-PPL routing algorithm we formerly proposed, are algorithms that achieve reduction of interference level among source-destination node pairs, rejection probability and routing complexity. Again, those previously proposed algorithms do not take into account the dynamic nature of traffic load. In fact, future traffics are unknown, but, amount of previous traffic over link can be measured. Therefore, this is the motivation of our proposed algorithm, the D-PPL. The D-PPL algorithm is improved based on the R-PPL routing algorithm by integrating traffic-per-link parameters. The parameters are periodically updated and are dynamically changed depended on current incoming traffic. The D-PPL tries to reserve residual bandwidth to service future request by avoid routing through those high traffic-per-link parameters. We have developed extensive MATLAB simulator to evaluate performance of the D-PPL. From simulation results, the D-PPL improves performance of MPLS on-line routing in terms of rejection probability and total throughput.

• Proceedings of the IEEK Conference
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• 2000.06a
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• pp.271-274
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• 2000

In this paper, the distortion of an electrical pulse with rise/fall time resulting from dispersion and reflection as it propagates along a tapered microstrip line is investigated, and the delay time and distortion rate with respect to input and load impedances are analyzed on triangular and exponential tapered lines and analyzed the influence of the reflection and frequency dispersion on the distorted voltage wave in the tapered lines. The observed overshoot in front of the distorted wave is caused due to the frequency dispersion and the sustained tail of that comes from the reflection in the tapered line.

• Proceedings of the KIPE Conference
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• 2000.07a
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• pp.103-106
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• 2000

In this paper a communication system that is not using the communication line but power line is presented. It will be very useful for an information-oriented society with tele-metering and home automation. Conventional system has a difficulty in transmitting information due to decreasing communication voltage and increasing carrier, current. Proposed idea is a special type switching amplifier system which has a low inner resistance. It can provide reactive power and dose not have low impedance between the transceivers. This new system is proposed to overcome the loss of conductor load in a PLC system.

• Journal of information and communication convergence engineering
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• v.7 no.4
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• pp.453-458
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• 2009

This paper presents two methods of designing a Broadband Impedance Matching (BIM) circuit for maximizing a power line communication (PLC) equipment (or Modem) signal injection into its load at any power line connection port. This optimal (BIM) circuit design is achieved in two phases: Butterworth gain function and Tchebycheff gain function. According to the comparison of simulation and practical results, the performances of two gain functions on BIM are discussed.

• 제어로봇시스템학회:학술대회논문집
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• 1991.10a
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• pp.232-237
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• 1991

Digital Variable Structure Controller(DVSC) is proposed to control variable speed recirculating pump for hot-water heating control system. In this study, nonlinear sliding line is used beyond output error boundary layer and PID sliding line is used within the layer. For long dead time compensation, constraint is added to Smith predictor algorithm. Steady state error is eliminated by using the proposed sliding line in spite of heating load change. By decreasing sampling time, good sliding motion is yielded but system output noise bv flow dynamics is amplified.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.33 no.6
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• pp.241-246
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• 1984

The power system scheduling process is formulated as an optimization problem with linear inequality constraints. AC Loadflow method is used for the problem solution and line losses are considered. The constraints under consiceration are generator power limits, load schedding limits and line capacity limits. In solving the objective function the Dual Relaxation method is adopted. Tests indicate that the method is practical for real time applications.

• Journal of the Korea Computer Industry Society
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• v.5 no.9
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• pp.851-858
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• 2004

This paper presents improved teaching and learning GUI for easily analysis tool of load flow of power system with database function for searching solution. In this paper includes not only contingency analysis function but also searching function of conditional solution sets from database of solution for various load levels. The GUI is friendly for study for power system operation and control because picture provide a better visualizing of relationshipsbetween input parameters and effects than a tabula type result. This GUI enables topologyand the output data of load flow for line outages to be shown on same picture page. Userscan input the system data for power flow on the the picture and can easily see the theresult diagram of bus voltage, bus power, line flow. It is also observe the effects of different types of variation of tap, shunt capacitor, loads level, line outages. Proposed GUI has been studied on the Ward-Hale 6-Bus system.

• The Journal of Korean Association of Computer Education
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• v.15 no.1
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• pp.55-64
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• 2012

The purpose of this study is to identify how realism of pedagogical agent can have impacts on persona effect and cognitive load factors. Eighty-two college students participated, and the independent variables of this study were the degree of image details and presence of gesture. The degree of image details were picture, illustration, and line-drawing. The $3{\times}2$ factorial design was applied. There was a significant interaction effect on the engaging of agent persona instrument. When the learners were under the condition of line-drawing agent without gesture, they showed the highest score on engaging of the agent persona instrument. Regarding the cognitive load factors, when learners under the condition of line-drawing showed the highest score of self-evaluation.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.3
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• pp.531-535
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• 2010

345kV Incheon Thermal Power Plant Transmission Line Collapse Analysis and Countermeasures. The Typhoon Galmaegi which had been formed in July 15, 2008 diminished into a tropical cyclone and cooled the air above the West Sea. The cooled air colliding with the warm inland air caused a strong whirlwind at some places in the west seaside; the whirlwind battered the 345kV Incheon Thermal Power Plant Transmission Line to be collapsed. The resistance of transmission towers against wind pressure, one of the key elements in transmission line engineering, is designed to endure the pressure corresponding to the maximum instantaneous wind speed. Before the above accident happened, no transmission line has ever been collapsed by a whirlwind. So this paper is aimed to analyze causes that collapsed 345kV Incheon Thermal Power Plant transmission line and to introduce countermeasures.

• Proceedings of the KIEE Conference
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• 2005.07d
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• pp.2986-2988
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• 2005

To improve the reliability of power-line communication systems, the measurement and analysis has been proceeded in many power-line channel environments. In spite of the wired channel, power line channel has many multi-paths that are changing with load-variation, line-interconnection, impedance mismatching and so on. We accordingly need an analysis method based on the multi-path channel impulse response. Recently, a method to describe the homogeneous Power-line network has been published[1]. In this paper the modified method that can describe both the homogeneous and non -homogeneous power-line network has presented.