• The Journal of the Korea Contents Association
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• v.7 no.12
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• pp.254-261
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• 2007

In this paper, we propose a blind equalization method for advanced terrestrial digital multimedia broadcasting (AT-DMB) systems which use hierarchical modulation. The AT-DMB system adopts hierarchical 16-ary quadrature amplitude modulation (16-QAM) to ensure backward-compatibly with the differential quadrature phase shift keying (DQPSK) signal of the legacy terrestrial digital multimedia broadcasting (T-DMB) systems and to support higher transmission rate. Due to the hierarchical modulation, the conventional T-DMB signal and the additional signal have different error rate at same signal to noise ratio (SNR). By weighting the decided symbols differently according to the reliability of the symbols, i.e., high priority symbol with low error rate and low priority symbol with high error rate, we can improve the channel estimation accuracy. In this paper, we analyze SNR loss by hierarchical modulation and confirm it through simulations. Moreover, through simulations, we verify that the proposed weighting method improve BER compared to the no-weighting method.

• The Transactions of the Korea Information Processing Society
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• v.7 no.8
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• pp.2411-2420
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• 2000

Far detecting variaus camputer intrusians effectively, many researches have develaped the misuse based intrusian detectian systems. Recently, warks related ta anamaly detectian, which have impraved the drawback .of misuse detectian technique, have been under focus. In this paper, a new clustering algarithm based an support constraint far generating user's narmal activity patterns in the anamaly detectian can praposed. It can grant a user's activity .observed recently ta mare weight than that .observed in the past. In order that a user's anamaly can be analyzed in variaus angles, a user's activity is classified by many measures, and far each .of them user's narmal patterns can be generated. by using the proposed algarithm. As a result, using generated narmal patterns, user's anamaly can be detected easily and effectively.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.1
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• pp.27-37
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• 1993

In unmanned machining, One of the most essential issue is the tool management system which includes controlling. identification, presetting and monitoring of cutting tools. Especially the monitoring of tool wear and fracture may be the heart of the system. In this study a computer vision based tool monitoring system is developed. Also an algorithm which can determine the tool condition using this system is presented. In order to enhance practical adaptability the vision system through which two modes of images are taken is located over the rake face of a tool insert. And they are analysed quantitatively and qualitatively with image processing technique. In fact the morphologies of tool fracture or wear are occurred so variously that it is difficult to predict them. For the purpose of this problem the pattern recognition is introduced to classify the modes of the tool such as fracture, crater, chipping and flank wear. The experimental results performed in the CNC turning machine have proved the effectiveness of the proposed system.

• Journal of KIISE:Databases
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• v.37 no.1
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• pp.50-55
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• 2010

Duplicate documents in blog service system are one of causes that deteriorate both of the quality and the performance of blog searches. Unlike the WWW environment, the creation of documents is reported every time in blog service system, which makes it possible to identify the original document from its duplicate documents. Based on this observation, this paper proposes a novel method for detecting duplication documents in blog service system. This method determines whether a document is original or not at the time it is stored in the blog service system. As a result, it solves the problem of duplicate documents retrieved in the search result by keeping those documents from being stored in the index for the blog search engine. This paper also proposes three indexing methods that preserve an accuracy of previous work, Min-hashing. We show most effective indexing method via extensive experiments using real-life blog data.

• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.318-322
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• 2006

댐군 운영 문제는 여러 상충되는 목적 및 구성 요소들 간의 타협, 조정을 위한 다목적 특성을 갖고 있다. 본 연구의 목적은 댐군 연계 운영 문제에 대해 다기준 의사결정 기법을 적용하여 최선의 운영 계획을 수립하는 것이다. 이를 위해 순위선호(outranking) 관계와 유사기준(pseudo-criteria)을 기반으로 해서 여러 선호 대안을 선정하는 데 유용한 ELECTRE (ELimination Et Choice Translating REality)를 적용하고자 한다. ELECTRE IS는 주어진 후보 대안들 중에서 원하는 수의 대안을 선정하는 데 유용하다. 그러나 기존의 ELECTRE IS는 대안선정 과정에서 의사결정자에게 기준들의 가중치(weight), 유사기준판정 경계치(pseudo-criteria thresholds), 그리고 일치판정 기준비율(concordance level)의 매개변수에 대한 설정을 요구하고 이들의 설정 상태에 따라 도출되는 대안의 수가 달라질 수 있는 성질을 갖고 있다. 특히 일치판정 기준비율은 ELECTRE IS의 최종적인 순위선호 관계의 형성여부에 결정적 영향을 주어 매개변수의 아주 작은 변화에도 선정되는 대안의 수가 달라질 수 있다. 따라서 실제 ELECTRE IS를 적용하여 원하는 수의 대안을 선정하기 위해서는 일치판정 기준비율에 대한 반복적용이 불가피하다. 이에 본 연구에서는 CoMOM (Coordinated Multireservoir Operating Model)을 활용한 댐군 연계운영 시 제시되는 파레토 최적해 집합(Pareto set)중에서 최선의 파레토 최적해를 선정할 때 ELECTRE IS의 수학적 구현 모형을 활용할 것을 제안하고 그 방법론을 제시한다. 제안된 모형은 혼합정수계획모형으로서 ELECTRE IS를 적용하는 과정에서 일치판정 기준비율을 자동으로 도출하고, 궁극적으로 많은 반복 없이 원하는 수나 그에 근사한 수의 선호대안(핵심대안)을 도출할 수 있는 특징을 갖고 있다. 이 모형을 낙동강 수계의 댐군 연계운영 문제에 적용해 보고, 핵심대안을 효율적으로 도출할 수 있음을 보인다.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.41 no.5
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• pp.269-274
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• 2004

In this paper, proposed is the dual-mode algorithm of blind decision feedback equalizer (DFE) for digital terrestrial television signals. According to channel impairments, the proposed dual-mode algorithm for blind DFE operates in decision-directed mode or in blind mode of operation. The error signals being used in tap update of the equalizer are generated in the best mode of operations, so that the confidence of equalizer tap coefficient update is more accurate. As a result, it is possible to track the channel characteristics variations by automatic switching over between two modes of operations. For 8-level vestigial sideband modulated digital television signals, the mean square errors and symbol error rates of the proposed algorithm are compared with those of conventional methods. And the usability of the proposed scheme is assessed by computer simulations under various static and dynamic multipath channel environments.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.8
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• pp.5310-5317
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• 2014

Landslides occur in Korea every year because it has numerous mountainous regions and approximately two-thirds of the annual rainfall falls in Summer. Therefore, it is important to predict potential areas of landslides and minimize the damage in advance to protect property and human life. Therefore, in the present study, the potential danger areas were extracted from a digital map, digital forest map, digital forest site environmental map, and digital geologic map to estimate the landslide hazard. In addition, the assessment of landslide danger was analyzed by first and second estimations based on the criteria from the Korea Forest Research Institute using a GIS technique, which was finally judged by a field investigation.

• Journal of Korean Tunnelling and Underground Space Association
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• v.12 no.6
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• pp.463-473
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• 2010

A new approach for prediction of a fault zone ahead of tunnel face by using statistical control charts is suggested and applied to the construction site. $x-R_s$ control charts of RMR parameters were investigated as approaching and passing through fault zone. The abnormal signal from the control charts was observed and analyzed based on statistical criteria. Fault zones in the application area were predicted in advance using this method and it was verified by comparing with observation data like horizontal boring and face mapping.

• Proceedings of the Korean Society of Computer Information Conference
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• 2021.07a
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• pp.469-470
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• 2021

본 논문에서 제안하는 슈팅게임 제자작 방법은 게임엔진으로 언리얼 엔진 4(Unreal Engine 4)를 사용하고 있다. 기존의 언리얼 엔진 기반의 게임은 총알에 데미지 판정 기법을 사용하지만, 슈팅게임 제작에서 중요한 요소인 정확성을 높이기 위해서 Line Trace 기술을 활용하는 기법을 제안한다.

• 방재와보험
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• s.110
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• pp.30-37
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• 2005

가정에서 사용되는 가전기기 중에서도 특히 소비전력이 높은 모발건조기는 물리적 충격에 약하고, 물기 등에 노출되는 경우 순식간에 고열이 발생해 화재로 이어질 가능성이 큰것으로 나타났다. 모발건조기의 부주의한 방치로 인한 화재의 확산 패턴 및 과학적 조사 기법을 통해 쉽게 노출되는 전기안전 사고의 방지에 경각심을 일깨워야 할 때이다.