• 한국음향학회:학술대회논문집
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• 한국음향학회 1998년도 학술발표대회 논문집 제17권 2호
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• pp.211-214
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• 1998

TCM(Trellis-Coded Modulation)은 대역폭과 전력이 제한된 채널환경에서 채널부호화 기술과 변조기술을 결합시켜 대역폭의 증가없이 에러정정능력을 개선시키는 통신 기술이다. 본 논문에서는 TCM 신호의 복호시 사용되는 Viterbi decoder에서 traceback depth의 감소에 따른 BER(Bit Error Rate)의 증가를 개선하기 위해 수신부에서 설정하는 traceback depth를 주기로 blocking하여 TCM encoder의 입력시퀀스에 zero padding bits를 추가시키는 새로운 알고리듬을 제안한다. 모의실험결과, traceback depth가 50인 hard decision의 경우 약 2~2.5dB, 4-level soft decision과 8-level soft decision의 경우 약 0.3~2dB의 coding gain을 얻을 수 있었다.

• 한국통신학회논문지
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• 제13권3호
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• pp.193-203
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• 1988

본 논문에서는 ISDN U-인터페이스에서 결정 궤환을 이용한 반향 제거기를 제시하고 추정 반복 알고리즘을 사용하여 다른 선형 반향 제거기와 성능을 비교 분석하였다. 결정 궤환-반향 제거기는 다른 선형 반향 제저기에 비해 정상 상태의 평균 자승 오차가 감소하였다. 동일한 수렴 조건에서 반향 제저기의 성능은 채널 특성에 관계없이 거의 동일했다.

• Journal of Information Technology Applications and Management
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• 제22권2호
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• pp.113-122
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• 2015

Collective intelligence can be an influential factor of decision-making based on collaboration and information exchange between individuals. Our study explores whether collective intelligence can mitigate the loss aversion effect, bias and error in human judgment, and collective intelligence in online communities can reduce the loss aversion effect. Our community settings display both individual-level and group-level loss aversion effect, investigate effective collective intelligence characteristics like investment commitment, participant experience. Using a multi-method approach our research comprises a web-based experiment with 100 participants investing 3 situations from a real-world community, data from a survey measuring loss aversion behavior of participants. The results suggest the loss aversion effect mitigates under the online-circumstance. Overall, our results suggest that, while collective intelligence mitigates the loss aversion effect, participants do not transfer these results to other settings.

• 전자공학회논문지S
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• 제34S권11호
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• pp.16-24
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• 1997

In order to prevent the presence of the residual phase difference at the discriminator output by the existing AFC techniques, we propose a new automatic frequency control(AFC) tracking algorithm for QPSK demodulation at the digital direct broadcasting satellite(DBS) receiver, which we call a rotational decision-directed AFC(RDDAFC). The RDDAFC rotates the decision boundary for the kth received symbol by the frequency deterctor output of the (k-1)th received symbol. Tracking performances of carrier frequency offset by the proposed RDDAFC algorithm are evaluated through computer simulations under the practical DBS channel conditions with a carrier frequency offset of 2.3MHz when S/N equals 2dB. Test results show that the total pull-in time of the RDDAFC is 1.697msec for 10$^{-3}$ SER before forwared error correction at the receiver.

• International Journal of Internet, Broadcasting and Communication
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• 제9권1호
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• pp.72-80
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• 2017

In this work, an efficient transmit antenna selection approach for the quadrature spatial modulation (QSM) systems is proposed. The conventional Euclidean distance antenna selection (EDAS)-based schemes in QSM have too high computational complexity for practical use. The proposed antenna selection algorithm is based on approximation of the EDAS decision metric employed for QSM. The elimination of imaginary parts in the decision metric enables decoupling of the approximated decision metric, which enormously reduces the complexity. The proposed method is also evaluated via simulations in terms of symbol error rate (SER) performance and compared with the conventional EDAS methods in QSM systems.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 추계학술대회 논문집 학회본부
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• pp.192-194
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• 1995

An improved filter for tracking a maneuvering target is presented. The proposed filter consists of two kalman filters based on different dynamic models and double decision logic. The use of double decision logic for the maneuver onset and ending detection leads to reduction in estimation error. This decision rule is based on evidence theory, Dempster-Shafer theory, which is extended in order to be applicable in the tracking problem. Simulation results show that the proposed filter performs better than IMM at a lower computational load.

• 대한전자공학회논문지
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• 제27권2호
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• pp.9-15
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• 1990

本 論文에서는 線刑 2元 블럭 符號에 대한 軟判定 復號 알고리듬을 제안하였다. 이 알고리듬은 블록 誤謬 確率을 最小化하기 위한 것이다. 提案된 알고리듬을 기存의 다른 復號法과 비교하기 위하여(7,4) Hamming 符號와(23,12)Golay 符號에 대한 컴퓨터 시뮬레이션을 수행하였다. 그 결과, 提案된 알고리듬의 乎均 硬判定 復號 回數는 항상 2以下이며 信號對 雜音比가 충분히 클때 1에 접근하였다. 즉, 기存 다른 復號法에 비하여 復號의 複雜度가 減少되었음을 확인하였다.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 1993년도 Fifth International Fuzzy Systems Association World Congress 93
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• pp.1342-1345
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• 1993

In the cellular mobile communications as decreasing the cell radius to increse the reuse factor of frequencies, the handoff requests are increasing so that the efficient handoff decision making becomes a crucial problem. In this simulation study, we evaluate a set of handoff algorithms based on fuzzy-multicriteria decision making. These algorithms uses the parameters including the received signal strength intensity, the bit error rate and the distance between a mobile station and a base station. We compare the fuzzy algorithms in terms of call block ratio and handoff request ratio and call force ratio, and show the applicability of those algorithms in the cellular mobile communication systems.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제8권2호
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• pp.140-145
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• 2008

In this paper, we constructed the advanced cargo monitoring system for liquid cargo tankers which embedded the Decision Support System (DSS) based on the International Ship Management Code (ISM Code). To make this system, we first organized a base of expert's knowledge concerning liquid tanker operations that largely affect ocean accidents. We can find out the knowledge via inference method which simply imitates the fuzzy inference method. Based on this expert's knowledge, we constructed the DSS that provides a code of conduct for operating cargo tanks safely. The proposed monitoring system could eliminate human error when confronting dangerous situations, so the system will help sailors to operate cargo tanks safely.

• 통합자연과학논문집
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• 제4권1호
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• pp.31-37
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• 2011

Various algorithms and system development are being required to support the advanced decision making of navigation information support system because of a serious loss of lives and property accidents by officer's error like as carelessness and decision faults. Much of researchers have introduced the techniques about the systems, but they hardly consider environmental factors. In this paper, We collect the context information in order to assess the risk, which is considered the various factor of the sailing ship, then extract the features of knowledge context, which is to apply the weight of correlation coefficients among data in context information. We decide the risk after the extract features through the classification and prediction of context information, and compare the value accuracy of proposed method in order to compare efficiency of the weighted value with the non-weighted value. As a result of experience, we know that the method of weight properties effectively reflect the marine environment because the weight accurate better than the non-weighted.