• 한국멀티미디어학회논문지
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• 제25권1호
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• pp.61-71
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• 2022

When communication such as light, radio wave, or magnetic field is used underwater, the communication distance is very short, so sound waves are mainly used. However, by combining the strengths of each medium and communicating, stable communication may be possible. Underwater multi-media communication requires a protocol stack that supports it, which is very complex. To this end, this paper proposes a standard protocol stack and modeling technique to enable easy protocol stack modeling for the purpose. In fact, in this paper, a random model was created and analyzed through the proposal of modeling elements and similarity measurement methods, and as a result, it was analyzed that it was very helpful in creating a new model based on a standard model.

• 한국정보전자통신기술학회논문지
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• 제7권3호
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• pp.126-131
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• 2014

본 논문에서는 웨이블릿 변환을 통하며 QRS complex를 검출 하며, 32비트 고정 소수점 연산이 가능한 프로세서에도 동작하도록 알고리즘 최적화 기법을 제시한다. 먼저 입력 ECG 신호를 밴드 패스 필터를 통과 시키고, 3개의 서로 다른 웨이블릿 함수를 하나로 병합한 웨이블릿 함수를 이용하여 웨이블릿 변환을 하며, 다음으로 시간 평균 함수를 뒤에 마지막으로 QRS complex를 검출 한다. 제안 알고리즘은 MIT-BIH arrhythmia database에 적용하여 검증한다. 모든 과정은 32비트 고정 소수점 연산으로 구현되며, 삼각함수 같은 복잡한 연산은 테이블화 하였다. 검출 알고리즘은 컴퓨터 시뮬레이션을 통해 평가 한다.

• 한국정보전자통신기술학회논문지
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• 제3권3호
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• pp.45-50
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• 2010

본 논문에서는 운동 중 실시간 구현을 위해 정확한 QRS 검출이 가능한 이산 웨이블릿 연산을 임펄스 응답으로 근사화 하여 연산량을 줄였다. 또한, 지속적인 QRS 검출로부터 부정맥, 빈맥 그리고 서맥등의 정보를 제공한다. 제안 알고리듬은 운동 중 수집된 생체신호를 컴퓨터 시뮬레이션을 통해 평가한다.

• 한국통신학회논문지
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• 제21권9호
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• pp.2456-2469
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• 1996

A digital satellite communication channel has a nonlinearity with memory due to saturation characeristis of the high poer amplifier in the satellite and transmitter/receiver linear filter used in the overall system. In this paper, we propose a complex radial basis function network(CRBFN) based adaptive equalizer for compensation of nonlinearities in digital satellite communication channels. The proposed CRBFN untilizes a complex-valued hybrid learning algorithm of k-means clustering and LMS(least mean sequare) algorithm that is an extension of Moody Darken's algorithm for real-valued data. We evaluate performance of CRBFN in terms of symbol error rates and mean squared errors nder various noise conditions for 4-PSK(phase shift keying) digital modulation schemes and compare with those of comples pth order inverse adaptive Volterra filter. The computer simulation results show that the proposed CRBFN ehibits good equalization, low computational complexity and fast learning capabilities.

• 한국정보전자통신기술학회논문지
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• 제3권3호
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• pp.73-80
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• 2010

상수 모듈러스 오차와 두확률 밀도 함수의 유클리드 거리에 기본을 둔 블라인드 알고리듬은 정보 이론적 학습 방법의 장점에도 불구하고 복소 채널의 위상 회전을 극복하지 못해 열악한 성능을 보인다. 이 논문에서는, 출력 전력이 다중 모듈러스 값의 근방에 있을 때 decision-directed 모드로 동작하는 기법을 정보 이론적 학습에 추가하므로서 복소 채널의 위상 회전 문제를 해결할 수 있음를 보였다. 복소 채널 모델과 16 QAM 방식에 대한 시뮬레이션 결과에서 복소 채널의 위상 회전 문제가 해결되어 현격한 성능 향상을 보였다.

• Bulletin of the Korean Chemical Society
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• 제26권8호
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• pp.1203-1208
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• 2005

A computational study based on molecular dynamics (MD) simulations was performed in order to explain the difference in aqueous solubilities of two flavonoid/$\beta$-cyclodextrin ($\beta$-CD) complexes, hesperetin/$\beta$-CD and naringenin/$\beta$-CD. The aqueous solubility of each flavonoid/$\beta$-CD complex could be characterized by complexwater interaction not by flavonoid-CD interaction. The radial distribution of water around each inclusion complex elucidated the difference of an experimentally observed solubility of each flavonoid/$\beta$-CD complex. The analyzed results suggested that a bulky hydrophobic moiety (-$OCH_3$) of B-ring of hesperetin nearby primary rim of $\beta$-CD was responsible for lower aqueous solubility of the hesperetin/$\beta$-CD complex.

• 한국정밀공학회지
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• 제14권11호
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• pp.135-146
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• 1997

This paper describes fault diagnosis method in complex system with hierachical structure similar to human body structure. Complex system is divided into unit, item and component. For diagnosing this hierarchical complex system, it is necessary to implement special neural network. Fault diagnosis system can forecast faults in a system and decide from current machine state signal information. Comparing with other diagnosis system for single fault, the developed system deals with multiple fault diagnosis comprising Hierarchical Neural Network(HNN). HNN consists of four level neural network, first level for item fault symptom classification, second level for item fault diagnosis, third level for component symptom classification, forth level for component fault diagnosis. UNIX IPC(Inter Process Communication) is used for implementing HNN wiht multitasking and message transfer between processes in SUN workstation with X-Windows(Motif). We tested HNN at four units, seven items per unit, seven components per item in a complex system. Each one neural newtork operate as a separate process in HNN. The message queue take charge of information exdhange and cooperation between each neural network.

• 한국대기환경학회지
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• 제13권3호
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• pp.207-214
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• 1997

We collected airborne complex mixtures in a industrial area of Yeochun, and examined whether these complex mixtures could affect gap junctional intercellular communication (GJIC) in a cultured WBF-344 rat liver epithelial cells (LEC). Since the reduction of GJIC plays an important role in chemical carcinogenesis, measurement of changes of GJIC is a meaningful method to screen carcinogenicity of these mixtures. High and low volume samples were dissolved in dimethyl sulfoxide (DMSO) and tested. Blank filter extractions were also examined for exclud-ing possible toxicity of filter itself, and TPA (12-O-tetradecanoylphorbol-13-acetate) and DMSO were used as positive and negative control, respectively. When the cells were exposed to samples at concentration below that required to maintain rather than 85% cell viability based on the result of neutral red uptake assay, maximal inhibition of GJIC was observed at 1hr after treatment with both high and low volume samples by scrape-loading dye transfer assay. In fluorescence recovery after photobleaching assay, recovery rates via gap junctions were 33%/min in high volume sample and 62%/min in low volume sample. In together, airborne samples collected in Yeochun inhibited GJIC in a cultured WBF-344 rat LEC. These results suggest airborne samples tested in this experiment may attribute to cause a certain type and degree of cancers in in vivo when exposured for some periods.

• 대한수학교육학회지:학교수학
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• 제12권4호
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• pp.507-530
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• 2010

본 연구는 지역별 우수수업 동영상에서 나타나는 수학적 의사소통이 어떻게 이루어지고 있는지를 분석하여 양질의 수업을 찾아 교사의 수업 관행에 도움을 주고자한 것이다. 교사와 교실 전체 간에 이루어지는 담화를 중심으로 수업을 분석하기 위해 다음과 같은 연구문제를 설정하였다. 첫째, 지역별 우수수업 동영상의 수학적 의사소통 수업유형은 무엇인가? 둘째, 지역별 우수수업은 의사소통이 어떻게 이루어지고 있는가? 셋째, 담화중심 수업의 수학적 의사소통 수준은 어떠한가? 공개된 24개의 수업을 수업 유형에 따라 분류한 결과 초등학교 수학 수업의 특성상 조작 중심수업 유형이 가장 많은 것으로 나타나 다른 유형의 수업도 좀 더 이루어질 필요가 있음을 알 수 있었다. 그리고 교수 학습 지도안에서 수학적 의사소통 능력을 고려한 수업은 5개이며 이 중 1개 수업만이 수학적 의사소통 능력을 인지적 영역에 포함시키고 있어, 수학적 의사소통 능력에 대해 교사가 정확히 알 필요가 있었다. 또한, 학생 간 질문하기를 수업에 반영할 필요가 있었다.

• 한국시스템다이내믹스학회:학술대회논문집
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• 한국시스템다이내믹스학회 2004년도 하계 학술대회 발표논문집
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• pp.109-128
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• 2004

The complexity of information and communication policy has been increasing due to its rapid changes and its expansions toward various fields. I used the2001, 2002 and 2003 White Papers on MIC(Ministry of Information and Communication Republic of Korea) as a reference and the Vensim PLE program to create a causal map. According to my analysis, no major feedback loop was found among the information and communication policies. Thus, it was impossible to conduct a causal map analysis on these policies. The causal map analysis is usually employed to understand a complex mechanism of entire policies by finding feedback loops among them. A lack of feedback loops makes it impossible to conduct the causal map analysis and means that the mechanism of such policies is even more complex to understand. The most important conclusion is that to consider feedback thought among the policies based on the systems thinking before making the policies.