• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.729-733
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• 2012

오산천 어류상 분석을 통하여 생물종의 다양성 및 존속성 확보를 위한 서식처별 어류군집의 특성을 밝히고 자연 하안 및 서식처 조성 시 적합한 어류상에 대한 기초자료를 제공하고자 하였다. 본 연구에서는 오산천 일원의 3개 지점을 대상으로 각 서식처별 어류상을 조사하였다. 조사 결과 대한민국 고유종 2종을 포함하여 전체 9종 144개체가 채집되었다. 오산천 조사 지점 모두 수질이 좋지 않았으며 어류상은 빈약하였다. 기흥저수지 유입부에서는 상대적으로 다른 지점보다 많은 종수와 개체수가 채집되어 오산천 복원 시 수질개선과 함께 오산천 상류로 서식지 확장을 통한 복원이 가능할 것으로 사료된다. 복원 대상종은 대한민국 고유종인 왜매치, 치리 및 얼록동사리와 하상의 상태를 개선할 수 있을 경우에는 참마자와 모래무지를 포함할 수 있을 것으로 사료된다.

• Journal of the Korean Chemical Society
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• v.12 no.4
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• pp.190-193
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• 1968

액체구조의 천이상태 이론을 용융염에 확장시켜 액체없이 상태합을 유도하였다. 이 상태함을 액체할로겐화알칼리들에 적용시켜 증기압, 몰부피, 엔트로피등의 열역학적 성질을 계산한 결과 측정치와의 좋은 일치를 보여주었다.

• Journal of the Korean Chemical Society
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• v.10 no.3
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• pp.129-132
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• 1966

It is known that almost all cyclohexane molecules are chair form in liquid state. Therefore, only chair form is considered in formulating the partition function for liquid cyclohexane, according to the Transient State Theory of Significant Liquid Structure proposed by Pak, Ahn and Chang. The thermodynamic quantities such as molar volume, vapor pressure, entropy of vaporization and compressibility of the liquid are calculated. The results are in good agreement with experimental values.

• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.409-409
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• 2017

유역단위에서 수문모델링을 수행함에 있어 토양수분은 물수지 관점에서 매우 중요한 인자로 고려된다. 더욱이, 최근 발생빈도가 커지고 있는 가뭄을 효과적으로 평가하고 예측하는 데에도 활용성이 매우 큰 것으로 인식되고 있다. 이러한 중요성에도 불구하고, 가용자료의 부족, 자료의 부정확성 등으로 인해 실제 유역모델링을 수행하는데 있어 활용도는 매우 적다. 이러한 점에서 본 연구에서는 동질성이 확보된 유역단위를 기준으로 다지점의 토양수분 자료를 추계학적으로 모의할 수 있는 기법을 개발하고자 한다. 토양함수자료는 지속성(persistence)이 매우 큰 특징을 가진다. 즉, 상태의 지속성이 크며 메모리가 오랫동안 유지된다는 점에서 추계학적 모의가 가능할 것으로 판단된다. 이러한 지속성을 이용함과 동시에 토양함수를 다양한 상태로 분리하고 이들 상태들간의 천이확률을 효과적으로 모의할 수 있다면 관측 토양함수 자료의 통계적 특성 재현이 가능하다. 본 연구에서는 용담댐 유역에 대해서 개발된 모형을 적용하고 활용성을 검토하고자 한다.

• Korean Journal of Ecology and Environment
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• v.43 no.3
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• pp.356-368
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• 2010

In this study, we applied approach of integrative star-plot area (SPA), chemical water quality and habitat conditions (QHEI) to diagnoze ecological conditions at the eight sampling sites of Sapkyo Stream. These outcomes were compared with biological health based on the Index of Biological Integrity (IBI) using fish assemblage. And then, we evaluated the integrative ecological health condition using the star-plot method. This approach based on the sum of all the star-plot areas over these water and habitat characteristics. It was developed to reflect an integrative assessment of the ecological health in the stream. The biological health, based on the model values of IBI indicating "fair-poor" condition according to the criteria. Physical habitat health, based on the QHEI, averaged 123 indicating a "good-fair" condition. Also, chemical health, based on simply BOD values indicating "poor grade" according to the criteria of the Ministry of Environment Korea (MEK). The SPA indicating that 50% of the all was impaired condition and the most sampling sites were downstream sites influenced by the point and non-point sources. Overall our results suggest that the ecological health impact was a combined effect of eutrophication and habitat degradations in the stream. The approach of SPA can be used as a tool to evaluate the integrative health of stream environment and to identify possible causes of observed effects.

• Journal of Korea Water Resources Association
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• v.32 no.6
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• pp.751-762
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• 1999

In this study, a 1-D laboratory experiment was conducted to investigate the characteristics of transient unsaturated solute transport by using two kinds of soils of which properties were known by test. Especially the TDR method which is proposed in this study was used to measure water content and solute concentration. As results, in the transient flow, the wetting front moves down rapidly, and the distribution of solute concentration near the wetting front showed the similar type of the water content distribution(semi-bell type). A numerical model HYDRUS was used to compare with the experimental results. Numerical results for the water movement are similar to experimental result. However, numerical results of the distribution of solute concentration are more scattered than experimental results. It means that measured dispersivity, numerical dispersion, adsorption coefficient, and soil sample size etc. should be considered in order to determine the dispersivity used in the numerical model. The present measuring method was proved to be superior to other formula and to be an available method to apply to solute transport test. The measuring error of the developed method is estimated smaller than 10% while water content is larger than 0.15.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.36C no.10
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• pp.47-55
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• 1999

In this paper, a new function hazard elimination algorithm is proposed for asynchronous circuit synthesis. In previous approach, function hazard is eliminated by using state graph which is obtained from the state assignment on STG(signal transition graph) representing transition relationship among signals. These algorithms can use conventional hazard removal and synthesis method applied in synchronous system, but it has much computational complexity and takes much time to handle the state graph. Although some hazard elimination algorithm from STG were proposed, it could not reduce the area overhead due to the addition of new signals. The proposed algorithm eliminate function hazard directly on STG and also control the number of minterms and product-term of added signal in order to minimize the area overhead. Experimental results on benchmark data shows that overall circuit area after hazard elimination is decreased about 15% on the average than that of previous method.

• The Journal of the Acoustical Society of Korea
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• v.8 no.1
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• pp.81-87
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• 1989

This paper discribes the method associated with modeling of Korean phonemes. Hidden Markov models(HMM's) may be viewed as an effective technique for modeling the inherent nonstationarity of speech signal. We propose a 3-state phoneme model to represent the sequentially changing characteristics of phonemes, i.e., transition-to-stationary-to-transition. Also we clarify that the duration of a phoneme is an important factor to have an effect in recognition accuracy and show that improvement in recognition rate can be obtained by using duration-dependent 3-state hidden Markov models.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.14 no.4
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• pp.412-422
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• 1989

The need to conversion between NAS and CEPT networks has led to the development of PCM standards conversion techniques, especially signalling conversion techniques. This paper contains a brief description and general overview of channel associated signalling(CAS) of 24-channel system and of 30-channel system. The line signalling conversion algorithm between two systems and the transition detection algorithm of call status is proposed. And this paper presents the effective inplementation techniques of these algorithm.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 2002.06a
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• pp.361-366
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• 2002

It has been reported that neural network with cyclic connections generates limit cycles. The dynamics of discrete time network with cyclic connections has been analyzed. But the dynamics of cyclic network in continuous time has not been known well due to its huge calculation complexity. In this paper, we study the dynamics of the continuous time network with cyclic connections and the effect of chaotic signal in the network for transitions between limit cycles.