• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.12A
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• pp.1133-1137
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• 2008

Sphere decoding is considered as one of the most promising methods for multiple-input multiple-output (MIMO) detection. This paper proposes a novel 2-level-search sphere decoding algorithm. In the proposed algorithm, symbol detection is concurrently performed on two levels of the tree search, which helps avoid discarding good candidates at early stages. Simulation results demonstrate the good performance of the proposed algorithm in terms of bit-error-rate (BER).

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.05a
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• pp.411-414
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• 2009

Many victims and property damages are caused in fires every year. In this paper, intelligent fire-detection systems with embedded fire-detection algorithms for early fire detection and alarm is proposed to reduce fire damages by using image processing technique, high speed digital signal processor(DSP) technique, and information technique. The fire detection algorithms used for the proposed systems consist of flame and smoke detection algorithms. If flame or smoke is detected respectively, the corresponding alarm signal can be transferred to management computer. And if flame and smoke is detected simultaneously, the fire alarm signal shall be generated. Through several experiments in the physical environment, it is shown that the proposed system works well without malfunction.

• Proceedings of the Korean Information Science Society Conference
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• 2002.04a
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• pp.280-282
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• 2002

기존의 네트워크에서는 혼잡상황이 감지된 이후에 네트워크 성능이 급격하게 저하된다. 이러한 문제를 해결하고자 RED(Random Early Detection)기법이 소개되어 게이트웨이에서 혼잡상황에 대하여 능동적으로 대처할 수 있는 알고리즘이 제시되었다. 하지만, RED는 매개변수 설정이라는 문제가 남아있다. 그리하여, 잘못된 변수값 설정으로 인한 네트워크 성능 저하가 현저하게 발생한다. 본 논문에서는 기존의 RED를 개선한 Effective RED를 제안한다. Effective RED는 RED 알고리즘의 문제점을 개선하여 네트워크의 상황에 맞추어 동적으로 매개 변수 값을 조정하는 알고리즘이다. 그리고, ns를 이용하여 Effective RED의 성능을 검증하였다.

• Proceedings of the Korean Information Science Society Conference
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• 2001.10c
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• pp.427-429
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• 2001

최근 라우터에서는 정체를 회피하고 전송률을 향상시키기 위한 능동적 큐 관리와 패킷 스케줄링에 대한 많은 논의가 이루어지고 있다. 본 논문은 라우터에서의 전송률 향상을 위한 Random Early Detection (RED) 알고리즘과 최근가지 변형된 RED알고리즘들의 특징을 살펴보고, RED라우터에 적용하여 실제로 종단 호스트(End-to-end)에서 전송 받는 패킷의 양을 창상하기 위한 선별적 처리 알고리즘을 제안한다.

• Journal of KIISE:Information Networking
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• v.31 no.1
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• pp.70-80
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• 2004

In order to reduce the increasing packet loss rates caused by an exponential increase in network traffic, the IETF(Internet Engineering Task Force) is considering the deployment of active queue management techniques such as RED(Random Early Detection). But, RED configuration has been a problem since its first proposal. This problem is that proposed configuration is only good for the particular traffic conditions studied, but may have detrimental effects if used in other conditions. While active queue management in routers and gateways can potentially reduce packet loss rates in the Internet, this paper has demonstrated the inherent weakness of current techniques and shows that they are unstable for tile various traffic conditions. The inherent problem with these queue management algorithms is that they all use static parameter setting. In this paper, in order to solve this problem, a new active queue management algorithm called SQM(Stabilized Queue Management) is proposed. This paper shows that it is easy to parameterize SQM algorithm to perform well under different congestion scenarios. This algorithm can effectively reduce packet loss while maintaining high link utilizations and is good for the various traffic conditions.

• Journal of KIISE:Information Networking
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• v.30 no.3
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• pp.437-447
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• 2003

In order to reduce the increasing packet loss rates caused by an exponential increase in network traffic, the IETF(Internet Engineering Task Force) is considering the deployment of active queue management techniques such as RED(Random Early Detection) algorithm. However, RED algorithm simple but does not protect traffic from high-bandwidth flows, which include not only flows that fail to use end-to-end congestion control such as UDP flow, but also short round-trip time TCP flows. In this paper, in order to solve this problem, we propose a simple fairness queue management scheme, called AFQM(Approximate Fair Queue Management) algorithm, that discriminate against the flows which submit more packets/sec than is allowed by their fair share. By doing this, the scheme aims to approximate the fair queueing policy Since it is a small overhead and easy to implement, AFQM algorithm controls unresponsive or misbehaving flows with a minimum overhead.

• The KIPS Transactions:PartC
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• v.10C no.1
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• pp.39-44
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• 2003

The network performance gets down during congestion periods to solve the problem effectively. A RED(Random Earl Detection) algorithm of the queue management algorithm is proposed and IETF recommends it as a queue management. A RED algorithm controls a congestion aspect dynamically. In analyzing parameters when static value of parameter is set in the gateway cannot be handled the status of current network traffic properly We propose the Effective RED algorithm to solve with the weakness of RED In this algorithm the maximum drop probability decides to accept or drop the interning packets, is adjusted dynamically on the current queue state for controlling the congestion phase effectively in the gateway. This algorithm is confirmed by computer simulation using the NS(Network Simulator)-2.

• The KIPS Transactions:PartC
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• v.13C no.5 s.108
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• pp.559-566
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• 2006

Virus throttling technique, one of many early worm detection techniques, detects the Internet worm propagation by limiting the connect requests within a certain ratio. The typical virus throttling detects worm occurrence by monitoring the length of delay queue with the fixed period of rate limiter. In this paper, we propose an algorithm that controls the period of rate limiter autonomically by utilizing the weighted average delay queue length and suggest various period determination policies that use the weighted average delay queue length as an input parameter. Through deep experiments, it is verified that the proposed technique is able to lessen inconvenience of users by reducing the connection delay time with haying just little effect on worm detection time.

• Journal of KIISE:Information Networking
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• v.34 no.3
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• pp.186-192
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• 2007

The virus throttling technique[5,6] is the one of well-known worm early technique. Virus throttling reduce the worm propagration by delaying connection packets artificially. However the worm detection time is not sufficiently fast as expected when the worm generated worm packets at a low rate. This is because the virus throttling technique use only delay queue length. In this paper we use the trend of weighted average delay queue length (TW AQL). By using TW AQL, the worm detection time is not only shorten at a low rate Internet worm, but also the false alarm does not largely increase. By experiment, we also proved our proposed algorithm had better performance.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.11B
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• pp.1289-1295
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• 2009

Premature ventricular contractions are the most common of all arrhythmias and may cause more serious situation like ventricular fibrillation and ventricular tachycardia in some patients. Therefore, the detection of this arrhythmia becomes crucial in the early diagnosis and prevention of possible life threatening cardiac diseases. Particularly, in the healthcare system that must continuously monitor people's situation, it is necessary to process ECG signal in realtime. In other words, design of algorithm that exactly detects R wave using minimal computation and classifies PVC is needed. So, R wave detection algorithm based adaptive threshold and window for the classification of PVC is presented in this paper. For this purpose, ECG signals are first processed by the usual preprocessing method and R wave was detected and adaptive window through R-R interval is used for efficiency of the detection. The performance of R wave detection and PVC classification is evaluated by using MIT-BIH arrhythmia database. The achieved scores indicate 99.33%, 88.86% accuracy respectively for R wave detection and PVC classification.