• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.2301-2306
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• 2005

Even if there are lots of researches on localization using 2D range finder in static environment, very few researches have been reported for robust real-time localization of mobile robot in uncertain and dynamic environment. In this paper, we present a new localization method based on ICP(Iterative Closest Point) algorithm for navigation of mobile robot under dynamic or uncertain environment. The ICP method is widely used for geometric alignment of three-dimensional models when an initial estimate of the relative pose is known. We use the method to align global map with 2D scanned data from range finder. The proposed algorithm accelerates the processing time by uniformly sampling the line fitted data from world map of mobile robot. A data filtering method is also used for threshold of occluded data from the range finder sensor. The effectiveness of the proposed method has been demonstrated through computer simulation and experiment in an office environment.

• Journal of Korean Institute of Industrial Engineers
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• v.34 no.3
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• pp.289-295
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• 2008

The shared-route decision algorithms in multicasting communications networks to provide the internet-based services such as IPTV, remote education/health, and internet broadcasting are presented. The three main measures of maximum delay, average delay and estimated delay between each node and member are adopted. Under the Mesh network with the uniform random cost between each node, the algorithm's performance is compared to the optimal solution with the minimum cost by all enumeration. The simulation results show that the algorithm using the estimated delay outperforms the other two methods.

• Journal of Biosystems Engineering
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• v.22 no.2
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• pp.227-236
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• 1997

Manual grading and sorting of red-ginsengs are inherently unreliable due to its subjective nature. A computerized technique based on optical and geometrical characteristics was studied for the objective quality evalution. Spectral reflectance of three categories of red-ginsengs - "Chunsam", "Chisam", "Yangsam" - were measured and analyzed. Variation of reflectance among parts of a single ginseng was more significant than variation among the quality categories of ginsengs. A PC-based image processing algorithm was developed to extract geometrical features such as length and thickness of body, length and number of roots, position of head and branch point, etc. The algorithm consisted of image segmentation, calculation of Euclidean distance, skeletonization and feature extraction. Performance of the algorithm was evaluated using sample ginseng images and found to be mostly sussessful.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.28B no.5
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• pp.369-381
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• 1991

In this paper, design algorithms for SMP(Single Mated Pair) and MMP (Multipli Mated Pair) structure of CCS (Common Channel Signaling) network are proposed through the study of the structure of CCS network. High reliability and fast messagy transfer time are the most important requirements for the CCS network. Based on it, three parameters such as monotraffic, reliability (maximum isolated SP(Signalling Point) number when any two STP(Signalling Transfer Points) fail and total network cost are defined. And the proposed algorithms different from preexisted algorithm that minimizes total network cost, maximize monotraffic with two constraints, reliability and total network cost. Comparing the experimental results of the proposed algorithms with those of the preexisted algorithm that minimizes total network cost, shows that the proposed algorithms produce a more reliable topology that has more monotraffic and a little higher total network cost. Additionaly, with the results of the proposed algorithms, SMP and MMP structures are compared.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.1
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• pp.1-7
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• 2011

Active power control scheme for distributed generation in microgrid consists of feeder flow control and unit power control. Feeder flow control is more useful than the unit power control for demand-side management, because microgrid can be treated as a dispatchable load at the point of common coupling(PCC). This paper presents detailed descriptions of the feeder flow control scheme for the hybrid system in microgrid. It is divided into three parts, namely, the setting of feeder flow reference range for stable hybrid system operation, feeder flow control algorithm depending on load change in microgrid and hysteresis control. Simulation results using the PSCAD/EMTDC are presented to validate the inverter control method for a feeder flow control mode. As a result, the feeder flow control algorithm for the hybrid system in microgrid is efficient for supplying continuously active power to customers without interruption.

• Proceedings of the IEEK Conference
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• 2001.06e
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• pp.9-12
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• 2001

Optical aligning process to archive the maximum optical coupling is crucial in many optical device manufacturing line such as laser diode module. Due to the three-dimensional nature of housing module and the aligning process for laser diode coupler, large amount of the manufacturing time, typically ranging from tens of minutes to an hour has to be devoted to the aligning process alone. In this thesis, we propose a new optical aligning process that employee a two-pass algorithm: coarse-to-fine search. Coarse search is a kind of blind search that finds the candidate region where the maximum optical coupling might mostly occur, followed by a fine searching that finds the maximum within the candidate region. The algorithm has been tested on 50 samples of cam-type laser diode modules, and the experimental results are analyzed in terms of aligning time and coupling efficiency.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.2B no.4
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• pp.214-218
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• 2002

In this paper, the effectiveness of three different control algorithms are thoroughly investigated via simulation and a proposed efficiency evaluation method of experimentation. Both the steady state and transient characteristics of each control algorithm along with its measured efficiency are analyzed. Finally, a novel two-mode maximum power point tracking (MPPT) control algorithm combining the constant voltage control and the incremental conduction (IncCond) methods is proposed to improve the efficiency of the 3KW PV power generation system at different insolation conditions. Experimental results show that the proposed two-mode MPPT control provides excellent performance at less than 30% insolation intensity, covering the whole insolation area without additional hardware circuitry.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.1 s.232
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• pp.45-52
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• 2005

A general approximate optimization technique by sequential design domain(SDD) did not save response values for getting an approximate function in each step. It has a disadvantage at aspect of an expense. In this paper, previous response values are recycled for constructing an approximate function. For this reason, approximation function is more accurate. Accordingly, even if we did not determine move limit, a system is converged to the optimal design. Size and shape optimization using approximate optimization technique is carried out with SDD. Algorithm executing Pro/Engineer and ANSYS are automatically adopted in the approximate optimization program by SDD. Convergence criterion is defined such that optimal point must be located within SDD during the three steps. The PLBA(Pshenichny-Lim-Belegundu-Arora) algorithm is used to solve approximate optimization problems. This algorithm uses the second-order information in the direction finding problem and uses the active set strategy.

• Journal of Information Processing Systems
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• v.13 no.6
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• pp.1467-1486
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• 2017

Fuzzy co-clustering is sensitive to noise data. To overcome this noise sensitivity defect, possibilistic clustering relaxes the constraints in FCM-type fuzzy (co-)clustering. In this paper, we introduce a new possibilistic fuzzy co-clustering algorithm based on information bottleneck (ibPFCC). This algorithm combines fuzzy co-clustering and possibilistic clustering, and formulates an objective function which includes a distance function that employs information bottleneck theory to measure the distance between feature data point and feature cluster centroid. Many experiments were conducted on three datasets and one artificial dataset. Experimental results show that ibPFCC is better than such prominent fuzzy (co-)clustering algorithms as FCM, FCCM, RFCC and FCCI, in terms of accuracy and robustness.

• JSTS:Journal of Semiconductor Technology and Science
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• v.16 no.4
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• pp.451-462
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• 2016

Photovoltaic energy conversion becomes main focus of many researches due to its promising potential as source for future electricity and has many advantages than the other alternative energy sources like wind, solar, ocean, biomass, geothermal etc. In Photovoltaic power generation multilevel inverters play a vital role in power conversion. The three different topologies, diode-clamped (neutral-point clamped) inverter, capacitor-clamped (flying capacitor) inverter and cascaded h-bridge multilevel inverter are widely used in these multilevel inverters. Among the three topologies, cascaded h-bridge multilevel inverter is more suitable for photovoltaic applications since each pv array can act as a separate dc source for each h-bridge module. This paper presents a single phase Cascaded H-bridge five level inverter for grid-connected photovoltaic application using sinusoidal pulse width modulation technique. This inverter output voltage waveform reduces the harmonics in the generated current and the filtering effort at the input. The control strategy allows the independent control of each dc-link voltages and tracks the maximum power point of PV strings. This topology can inject to the grid sinusoidal input currents with unity power factor and achieves low harmonic distortion. A PID control algorithm is implemented in Arm Processor LPC2148. The validity of the proposed inverter is verified through simulation and is implemented in a single phase 100W prototype. The results of hardware are compared with simulation results. The proposed system offers improved performance over conventional three level inverter in terms of THD.