• Journal of Korea Multimedia Society
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• v.16 no.4
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• pp.472-482
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• 2013

This paper proposes a wireless LAN topology configuration method for enhancing indoor location-awareness and improving network performance simultaneously. We first develop four objective functions that yield objective goals significant to the optimal design of a wireless LAN topology in terms of location-awareness accuracy and network performance factors. Then, we develop metaheuristic algorithms such as simulated annealing, tabu search, and genetic algorithm that examine the proposed objective functions and generate a near-optimal solution for a given objective function. Finally, four objective functions and metaheuristic algorithms developed in this paper are exploited to evaluate and measure the performance of the proposed wireless LAN topology configuration method.

• Journal of Internet Computing and Services
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• v.8 no.4
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• pp.17-29
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• 2007

This paper addresses a RNG based scatternet topology formation, self-healing, and routing path optimization for small-scale distributed environment, which is called RNG-FHR(Scatternet Formation, self-Healing and self-Routing path optimization) algorithm. We evaluated the algorithm using ns-2 and extensible Bluetoothsimulator called blueware to show that RNG-FHR does not have superior performance, but is simpler and more practical than any other distributed algorithms from the point of depolying the network in the small-scale distributed dynamic environment due to the exchange of fewer messages and local control. As a result, we realized that even though RNG-FHR is unlikely to be possible for deploying in large-scale environment, it surely can be deployed for performance and practical implementation in small-scale environment.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.6
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• pp.1538-1545
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• 1998

System reliability has been a major concern since the beginning age of the electronic digital computers. One of the modest ways of increasing reliability is to design fault-tolerant system. This paper propose a construction mechanism of fault-tolerant system for the general graph topology. This system has several spare nodes. Up to date, fault-tolerant system design is applied only to loop and tree networks. But they are very limited cases. New algorithm of this paper tried to have a capability which can be applied to any kinds of topologies without such a many restriction. the algorithm consist of several steps : minimal diameter spaning tree extraction step, optimal node decision step, original connectivity restoration step and finally redundancy graph construction step.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.50 no.10
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• pp.717-727
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• 2022

An algorithm is realized for estimating the component fault and health diagnosis such as a deterioration. Based on the turbofan engine health diagnosis model, from the health parameters which are estimated by a real time tracking filter, the outliers are eliminated efficiently by an effective median filter to minimize an false alarm. The difference between the fault and deterioration trends is identified by the detection measure for abrupt change, thereby the clear diagnosis classifying the fault and the health condition is possible. The effectiveness of the algorithm for fault and health diagnosis is verified from the simulated results of engine component faults and deterioration.

• Journal of Biomedical Engineering Research
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• v.25 no.4
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• pp.315-321
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• 2004

In this study, we proposed an adaptive feedback cancellation algorithm for multi-band digital healing aids. The adaptive feedback canceller (AFC) is composed of an adaptive notch filter (ANF) for feedback detection and an NLMS (normalized least mean square) adaptive filter for feedback cancellation. The proposed feedback cancellation algorithm is combined with a multi-band hearing aid algorithm which employs the MDCT (modified discrete cosine transform) filter bank for the frequency-dependent compensation of hearing losses. The proposed algorithm together with the MDCT-based multi-channel hearing aid algorithm has been evaluated via computer simulations and it has also been implemented on a commercialized DSP board for real-time verifications.

• Information and Communications Magazine
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• v.33 no.5
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• pp.3-11
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• 2016

자연계에서 존재하는 다양한 생명체는 자신들의 생존과 종의 번성을 위해 효율적인 행동 규칙을 만들어 진화해 왔다. 이러한 생명체의 다양한 생존원리로부터 착안을 하여 자연계가 아닌 다른 환경에서 적용이 가능하도록 알고리즘을 만들어 적용시키는 것을 생체모방 알고리즘이라 한다. 자연계의 환경자체가 불확실한 변화가 다양하게 포함되고 있으며, 제한된 자원 환경을 어떻게 효율적으로 활용하는가의 문제가 걸려 있음으로 인하여 이러한 생체모방 알고리즘은 적용환경의 변환에 빠른 적응력을 제공할 수 있고, 자원 제약형 환경에서 안정적으로 확장성과 적응성을 제공할 수 있어서 상호 운용성 측면에서 많은 이득을 줄 수 있다. 이와 같은 생체모방 알고리즘을 네트워크의 관점에서 적용시켜 보면, 전자의 경우에는 자율적인 네트워크 구성을 용이하게 제공할 수 있음을 나타내고, 후자의 경우에는 IoT 환경과 같은 자원 제약형 환경에서의 상호 운용성을 제공할 수 있다. 이렇듯이 생체모방 알고리즘을 네트워크에 접목시켜 연구하는 것은 최근의 네트워크 분야의 연구 이슈와 상호 보완적으로 작용하여 시너지 효과를 제공할 수 있다. 자연계의 군집 현상 및 동기화 현상을 네트워크 환경에서 적용하여 사용할 수 있는 생체모방 알고리즘 기술은 다양하게 존재하고 있으며 이를 활용하는 연구를 통해 SDN(Software Defined Networking)에서의 자율제어 네트워크 구성에 접목하거나 IoT 환경과 같은 자원 제약형 환경에서의 보다 효율적인 상호 연결성을 제공하는 방향으로 발전할 수 있다. 이러한 생체모방 자율제어 네트워크 환경 구현을 위해 기존의 OpenFlow 환경과 새로이 부각되는 P4: Programming Protocol-Independent Packet Processors 기술에 대해서 정리하여 향후 생체모방 자율제어 네트워크 구현 방안을 제시하고자 한다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.5
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• pp.525-532
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• 2004

In this paper, we proposed a multicast routing algorithm for QoS improvement in the wire/wireless integrated environment. We analyzed requests and characteristics of QoS, and then proposed a new algorithm that can improve QoS by adding node mobility to wire environment. This new algorithm constructs a dynamic multicast tree that can prevent a loss of packet and save the bandwidth. As a result of simulations comparing to another multicast algorithms, we showed that this new algorithm can simply and dynamically adjusts the construction of multicast tree with little delay and the most reducible bandwidth resources.

• Convergence Security Journal
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• v.6 no.2
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• pp.53-60
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• 2006

In the applications such as CAD or image processing, a variety of geometric objects are manipulated. A polygon in which all the edges are parallel to x- or y-axis is decomposed into simple rectangles for efficient handling. But, depending on the partitioning algorithms, the same region can be decomposed into a completely different set of rectangles in the number, size and shape of rectangles. So, it is necessary an algorithm that compares two sets of rectangles extracted from two scenes such as CAD or image to see if they represent the same region. This paper proposes an efficient algorithm that compares two sets of rectangles. The proposed algorithm is not only simpler than the algorithm based on sweeping method, but also reduces the number $O(n^2)$ of overlapped rectangles from the algorithm based on a balanced binary tree to O(nlogn).

• Proceedings of the KSRS Conference
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• 2009.03a
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• pp.280-285
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• 2009

1998년 8월부터 2005년 6월까지 한반도 주변 해역에서 현장관측한 해수의 고유 광특성(IOPs)과 외형적 광특성(AOPs) 자료들을 이용하여 원격반사도$(R_{rs}(\lambda))$와 성분별 흡광계수의 총 합 $(\alpha(\lambda)=\alpha_w(\lambda)+\alpha_{ph}(\lambda)+\alpha_{ss}(\lambda)+\alpha_{dom}(\lambda))$의 상관관계를 분석하고, $R_{rs}(\lambda)$ 밴드비를 이용하여 흡광계수 산출 알고리즘을 개발하였다. 파장에 따른 $R_{rs}(\lambda)$와 총합 $\alpha(\lambda)$의 상관관계는 반비례적인 관계를 보였고, 파장 443 nm일 때 상관도$(R^2)$는 0.717이다. $\alpha_{ph}(\lambda)$ 산출알고리즘은 엽록소의 흡광과 관련된 파장 490 nm와 부유물의 산란과 관련된 파장 555 nm의 $R_{rs}(\lambda)$ 밴드비의 함수 형태로 구성하였고, 파장 443 nm일 때 RMS 값은 0.223이다. $\alpha_{ss}(\lambda)$과 $\alpha_{dom}(\lambda)$ 산출 알고리즘은 용존유기물의 흡광과 관련된 파장 412 nm와 부유물의 산란과 관련된 파장 555 nm의 $R_{rs}(\lambda)$ 밴드비의 함수 형태로 구성하였고, 파장 412 nm일 때 RMS 값은 각각 0.324와 0.230이다. $\alpha_{ph}(\lambda),\;\alpha_{ss}(\lambda),\;\alpha_{dom}(\lambda)$ 산출 알고리즘들은 대체적으로 현장값보다 높게 추정하였고 스펙트럼들은 잘 재현해냈다. 추후 이에 대한 개선과 알고리즘의 검보정이 요구된다.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.15 no.3
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• pp.35-44
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• 2001

This paper presents a loop-based genetic algorithm for loss minimization of distribution systems by automatic sectionalizing switch operation in distribution systems. Genetic algorithm can be successfully applied to problem of loss minimization in distribution systems because it is suitable to solve combinatorial optimization problems. New loop-based string structure is proposed for generating the more feasible solutions, and the proposed restoration function converts infeasible solutions into feasible solutions. The loop-based genetic algorithm with sam adaptations have been applied to improve the computation time and convergence property. Numerical examples demonstrate the validity and effectiveness of the proposed methodology using a 32-bus and 69-bus system.